GPS USB dongle host

Dependencies:   mbed

Files at this revision

API Documentation at this revision

Comitter:
va009039
Date:
Mon Apr 30 14:24:46 2012 +0000
Child:
1:82eaa5761719
Commit message:

Changed in this revision

USBHostLite/usbhost_cpu.h Show annotated file Show diff for this revision Revisions of this file
USBHostLite/usbhost_err.h Show annotated file Show diff for this revision Revisions of this file
USBHostLite/usbhost_inc.h Show annotated file Show diff for this revision Revisions of this file
USBHostLite/usbhost_lpc17xx.c Show annotated file Show diff for this revision Revisions of this file
USBHostLite/usbhost_lpc17xx.h Show annotated file Show diff for this revision Revisions of this file
main.cpp Show annotated file Show diff for this revision Revisions of this file
mbed.bld Show annotated file Show diff for this revision Revisions of this file
usbgps.cpp Show annotated file Show diff for this revision Revisions of this file
usbgps.h Show annotated file Show diff for this revision Revisions of this file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/USBHostLite/usbhost_cpu.h	Mon Apr 30 14:24:46 2012 +0000
@@ -0,0 +1,35 @@
+/*
+**************************************************************************************************************
+*                                                 NXP USB Host Stack
+*
+*                                     (c) Copyright 2008, NXP SemiConductors
+*                                     (c) Copyright 2008, OnChip  Technologies LLC
+*                                                 All Rights Reserved
+*
+*                                                  www.nxp.com
+*                                               www.onchiptech.com
+*
+* File           : usbhost_cpu.h
+* Programmer(s)  : Ravikanth.P
+* Version        :
+*
+**************************************************************************************************************
+*/
+
+#ifndef  USBHOST_CPU_H
+#define  USBHOST_CPU_H
+
+/*
+**************************************************************************************************************
+*                                           TYPE DEFINITIONS OF DATA TYPES
+**************************************************************************************************************
+*/
+
+typedef  unsigned int    USB_INT32U;
+typedef  signed   int    USB_INT32S;
+typedef  unsigned short  USB_INT16U;
+typedef  signed   short  USB_INT16S;
+typedef  unsigned char   USB_INT08U;
+typedef  signed   char   USB_INT08S;
+
+#endif
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/USBHostLite/usbhost_err.h	Mon Apr 30 14:24:46 2012 +0000
@@ -0,0 +1,63 @@
+/*
+**************************************************************************************************************
+*                                                 NXP USB Host Stack
+*
+*                                     (c) Copyright 2008, NXP SemiConductors
+*                                     (c) Copyright 2008, OnChip  Technologies LLC
+*                                                 All Rights Reserved
+*
+*                                                  www.nxp.com
+*                                               www.onchiptech.com
+*
+* File           : usbhost_err.h
+* Programmer(s)  : Ravikanth.P
+* Version        :
+*
+**************************************************************************************************************
+*/
+
+#ifndef  USBHOST_ERR_H
+#define  USBHOST_ERR_H
+
+
+/*
+**************************************************************************************************************
+*                                        GENERAL DEFINITIONS
+**************************************************************************************************************
+*/
+
+#define  OK                        0
+#define  MATCH_FOUND               0
+
+/*
+**************************************************************************************************************
+*                                HOST CONTROLLER SPECIFIC ERROR CODES
+**************************************************************************************************************
+*/
+
+#define  ERR_TD_FAIL              -1
+
+/*
+**************************************************************************************************************
+*                                  MASS STORAGE SPECIFIC ERROR CODES
+**************************************************************************************************************
+*/
+
+#define  ERR_MS_CMD_FAILED       -10
+#define  ERR_BAD_CONFIGURATION   -11
+#define  ERR_NO_MS_INTERFACE     -12
+
+/*
+**************************************************************************************************************
+*                                      FAT SPECIFIC ERROR CODES
+**************************************************************************************************************
+*/
+
+#define  MATCH_NOT_FOUND         -20
+#define  ERR_FAT_NOT_SUPPORTED   -21
+#define  ERR_OPEN_LIMIT_REACHED  -22
+#define  ERR_INVALID_BOOT_SIG    -23
+#define  ERR_INVALID_BOOT_SEC    -24
+#define  ERR_ROOT_DIR_FULL       -25
+
+#endif
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/USBHostLite/usbhost_inc.h	Mon Apr 30 14:24:46 2012 +0000
@@ -0,0 +1,39 @@
+/*
+**************************************************************************************************************
+*                                                 NXP USB Host Stack
+*
+*                                     (c) Copyright 2008, NXP SemiConductors
+*                                     (c) Copyright 2008, OnChip  Technologies LLC
+*                                                 All Rights Reserved
+*
+*                                                  www.nxp.com
+*                                               www.onchiptech.com
+*
+* File           : usbhost_inc.h
+* Programmer(s)  : Ravikanth.P
+* Version        :
+*
+**************************************************************************************************************
+*/
+
+#ifndef  USBHOST_INC_H
+#define  USBHOST_INC_H
+
+/*
+**************************************************************************************************************
+*                                       INCLUDE HEADER FILES
+**************************************************************************************************************
+*/
+
+#include  "usbhost_cpu.h"
+#include  "usbhost_err.h"
+#include  "usbhost_lpc17xx.h"
+//#include  "usbhost_ms.h"
+#include  "mbed.h"
+
+
+#ifdef TARGET_LPC2368
+#error "There is no USB host on the LPC2368!"
+#endif
+
+#endif
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/USBHostLite/usbhost_lpc17xx.c	Mon Apr 30 14:24:46 2012 +0000
@@ -0,0 +1,819 @@
+/*
+**************************************************************************************************************
+*                                                 NXP USB Host Stack
+*
+*                                     (c) Copyright 2008, NXP SemiConductors
+*                                     (c) Copyright 2008, OnChip  Technologies LLC
+*                                                 All Rights Reserved
+*
+*                                                  www.nxp.com
+*                                               www.onchiptech.com
+*
+* File           : usbhost_lpc17xx.c
+* Programmer(s)  : Ravikanth.P
+* Version        :
+*
+**************************************************************************************************************
+*/
+ 
+/*
+**************************************************************************************************************
+*                                            INCLUDE HEADER FILES
+**************************************************************************************************************
+*/
+
+#include  "usbhost_lpc17xx.h"
+
+/*
+**************************************************************************************************************
+*                                              GLOBAL VARIABLES
+**************************************************************************************************************
+*/
+int gUSBConnected;
+
+volatile  USB_INT32U   HOST_RhscIntr = 0;         /* Root Hub Status Change interrupt                       */
+volatile  USB_INT32U   HOST_WdhIntr  = 0;         /* Semaphore to wait until the TD is submitted            */
+volatile  USB_INT08U   HOST_TDControlStatus = 0;
+volatile  HCED        *EDCtrl;                    /* Control endpoint descriptor structure                  */
+volatile  HCED        *EDBulkIn;                  /* BulkIn endpoint descriptor  structure                  */
+volatile  HCED        *EDBulkOut;                 /* BulkOut endpoint descriptor structure                  */
+volatile  HCTD        *TDHead;                    /* Head transfer descriptor structure                     */
+volatile  HCTD        *TDTail;                    /* Tail transfer descriptor structure                     */
+volatile  HCCA        *Hcca;                      /* Host Controller Communications Area structure          */ 
+          USB_INT16U  *TDBufNonVol;               /* Identical to TDBuffer just to reduce compiler warnings */
+volatile  USB_INT08U  *TDBuffer;                  /* Current Buffer Pointer of transfer descriptor          */
+
+// USB host structures
+// AHB SRAM block 1
+#define HOSTBASEADDR 0x2007C000
+// reserve memory for the linker
+static USB_INT08U HostBuf[0x200] __attribute__((at(HOSTBASEADDR)));
+/*
+**************************************************************************************************************
+*                                         DELAY IN MILLI SECONDS
+*
+* Description: This function provides a delay in milli seconds
+*
+* Arguments  : delay    The delay required
+*
+* Returns    : None
+*
+**************************************************************************************************************
+*/
+
+void  Host_DelayMS (USB_INT32U  delay)
+{
+    volatile  USB_INT32U  i;
+
+
+    for (i = 0; i < delay; i++) {
+        Host_DelayUS(1000);
+    }
+}
+
+/*
+**************************************************************************************************************
+*                                         DELAY IN MICRO SECONDS
+*
+* Description: This function provides a delay in micro seconds
+*
+* Arguments  : delay    The delay required
+*
+* Returns    : None
+*
+**************************************************************************************************************
+*/
+
+void  Host_DelayUS (USB_INT32U  delay)
+{
+    volatile  USB_INT32U  i;
+
+
+    for (i = 0; i < (4 * delay); i++) {    /* This logic was tested. It gives app. 1 micro sec delay        */
+        ;
+    }
+}
+
+// bits of the USB/OTG clock control register
+#define HOST_CLK_EN     (1<<0)
+#define DEV_CLK_EN      (1<<1)
+#define PORTSEL_CLK_EN  (1<<3)
+#define AHB_CLK_EN      (1<<4)
+
+// bits of the USB/OTG clock status register
+#define HOST_CLK_ON     (1<<0)
+#define DEV_CLK_ON      (1<<1)
+#define PORTSEL_CLK_ON  (1<<3)
+#define AHB_CLK_ON      (1<<4)
+
+// we need host clock, OTG/portsel clock and AHB clock
+#define CLOCK_MASK (HOST_CLK_EN | PORTSEL_CLK_EN | AHB_CLK_EN)
+
+/*
+**************************************************************************************************************
+*                                         INITIALIZE THE HOST CONTROLLER
+*
+* Description: This function initializes lpc17xx host controller
+*
+* Arguments  : None
+*
+* Returns    : 
+*
+**************************************************************************************************************
+*/
+void  Host_Init (void)
+{
+    PRINT_Log("In Host_Init\n");
+    NVIC_DisableIRQ(USB_IRQn);                           /* Disable the USB interrupt source           */
+    
+    // turn on power for USB
+    LPC_SC->PCONP       |= (1UL<<31);
+    // Enable USB host clock, port selection and AHB clock
+    LPC_USB->USBClkCtrl |= CLOCK_MASK;
+    // Wait for clocks to become available
+    while ((LPC_USB->USBClkSt & CLOCK_MASK) != CLOCK_MASK)
+        ;
+    
+    // it seems the bits[0:1] mean the following
+    // 0: U1=device, U2=host
+    // 1: U1=host, U2=host
+    // 2: reserved
+    // 3: U1=host, U2=device
+    // NB: this register is only available if OTG clock (aka "port select") is enabled!!
+    // since we don't care about port 2, set just bit 0 to 1 (U1=host)
+    LPC_USB->OTGStCtrl |= 1;
+    
+    // now that we've configured the ports, we can turn off the portsel clock
+    LPC_USB->USBClkCtrl &= ~PORTSEL_CLK_EN;
+    
+    // power pins are not connected on mbed, so we can skip them
+    /* P1[18] = USB_UP_LED, 01 */
+    /* P1[19] = /USB_PPWR,     10 */
+    /* P1[22] = USB_PWRD, 10 */
+    /* P1[27] = /USB_OVRCR, 10 */
+    /*LPC_PINCON->PINSEL3 &= ~((3<<4) | (3<<6) | (3<<12) | (3<<22));  
+    LPC_PINCON->PINSEL3 |=  ((1<<4)|(2<<6) | (2<<12) | (2<<22));   // 0x00802080
+    */
+
+    // configure USB D+/D- pins
+    /* P0[29] = USB_D+, 01 */
+    /* P0[30] = USB_D-, 01 */
+    LPC_PINCON->PINSEL1 &= ~((3<<26) | (3<<28));  
+    LPC_PINCON->PINSEL1 |=  ((1<<26)|(1<<28));     // 0x14000000
+        
+    PRINT_Log("Initializing Host Stack\n");
+
+    Hcca       = (volatile  HCCA       *)(HostBuf+0x000);
+    TDHead     = (volatile  HCTD       *)(HostBuf+0x100);
+    TDTail     = (volatile  HCTD       *)(HostBuf+0x110);
+    EDCtrl     = (volatile  HCED       *)(HostBuf+0x120); 
+    EDBulkIn   = (volatile  HCED       *)(HostBuf+0x130);
+    EDBulkOut  = (volatile  HCED       *)(HostBuf+0x140);
+    TDBuffer   = (volatile  USB_INT08U *)(HostBuf+0x150);
+    
+    /* Initialize all the TDs, EDs and HCCA to 0  */
+    Host_EDInit(EDCtrl);
+    Host_EDInit(EDBulkIn);
+    Host_EDInit(EDBulkOut);
+    Host_TDInit(TDHead);
+    Host_TDInit(TDTail);
+    Host_HCCAInit(Hcca);
+    
+    Host_DelayMS(50);                                   /* Wait 50 ms before apply reset              */
+    LPC_USB->HcControl       = 0;                       /* HARDWARE RESET                             */
+    LPC_USB->HcControlHeadED = 0;                       /* Initialize Control list head to Zero       */
+    LPC_USB->HcBulkHeadED    = 0;                       /* Initialize Bulk list head to Zero          */
+    
+                                                        /* SOFTWARE RESET                             */
+    LPC_USB->HcCommandStatus = OR_CMD_STATUS_HCR;
+    LPC_USB->HcFmInterval    = DEFAULT_FMINTERVAL;      /* Write Fm Interval and Largest Data Packet Counter */
+
+                                                        /* Put HC in operational state                */
+    LPC_USB->HcControl  = (LPC_USB->HcControl & (~OR_CONTROL_HCFS)) | OR_CONTROL_HC_OPER;
+    LPC_USB->HcRhStatus = OR_RH_STATUS_LPSC;            /* Set Global Power                           */
+    
+    LPC_USB->HcHCCA = (USB_INT32U)Hcca;
+    LPC_USB->HcInterruptStatus |= LPC_USB->HcInterruptStatus;                   /* Clear Interrrupt Status                    */
+
+
+    LPC_USB->HcInterruptEnable  = OR_INTR_ENABLE_MIE |
+                         OR_INTR_ENABLE_WDH |
+                         OR_INTR_ENABLE_RHSC;
+
+    NVIC_SetPriority(USB_IRQn, 0);       /* highest priority */
+    /* Enable the USB Interrupt */
+    NVIC_EnableIRQ(USB_IRQn);
+    PRINT_Log("Host Initialized\n");
+}
+
+/*
+**************************************************************************************************************
+*                                         INTERRUPT SERVICE ROUTINE
+*
+* Description: This function services the interrupt caused by host controller
+*
+* Arguments  : None
+*
+* Returns    : None
+*
+**************************************************************************************************************
+*/
+
+void USB_IRQHandler (void) __irq
+{
+    USB_INT32U   int_status;
+    USB_INT32U   ie_status;
+
+    int_status    = LPC_USB->HcInterruptStatus;                          /* Read Interrupt Status                */
+    ie_status     = LPC_USB->HcInterruptEnable;                          /* Read Interrupt enable status         */
+ 
+    if (!(int_status & ie_status)) {
+        return;
+    } else {
+
+        int_status = int_status & ie_status;
+        if (int_status & OR_INTR_STATUS_RHSC) {                 /* Root hub status change interrupt     */
+            if (LPC_USB->HcRhPortStatus1 & OR_RH_PORT_CSC) {
+                if (LPC_USB->HcRhStatus & OR_RH_STATUS_DRWE) {
+                    /*
+                     * When DRWE is on, Connect Status Change
+                     * means a remote wakeup event.
+                    */
+                    HOST_RhscIntr = 1;// JUST SOMETHING FOR A BREAKPOINT
+                }
+                else {
+                    /*
+                     * When DRWE is off, Connect Status Change
+                     * is NOT a remote wakeup event
+                    */
+                    if (LPC_USB->HcRhPortStatus1 & OR_RH_PORT_CCS) {
+                        if (!gUSBConnected) {
+                            HOST_TDControlStatus = 0;
+                            HOST_WdhIntr = 0;
+                            HOST_RhscIntr = 1;
+                            gUSBConnected = 1;
+                        }
+                        else
+                            PRINT_Log("Spurious status change (connected)?\n");
+                    } else {
+                        if (gUSBConnected) {
+                            LPC_USB->HcInterruptEnable = 0; // why do we get multiple disc. rupts???
+                            HOST_RhscIntr = 0;
+                            gUSBConnected = 0;
+                        }
+                        else
+                            PRINT_Log("Spurious status change (disconnected)?\n");
+                    }
+                }
+                LPC_USB->HcRhPortStatus1 = OR_RH_PORT_CSC;
+            }
+            if (LPC_USB->HcRhPortStatus1 & OR_RH_PORT_PRSC) {
+                LPC_USB->HcRhPortStatus1 = OR_RH_PORT_PRSC;
+            }
+        }
+        if (int_status & OR_INTR_STATUS_WDH) {                  /* Writeback Done Head interrupt        */
+            HOST_WdhIntr = 1;
+            HOST_TDControlStatus = (TDHead->Control >> 28) & 0xf;
+        }            
+        LPC_USB->HcInterruptStatus = int_status;                         /* Clear interrupt status register      */
+    }
+    return;
+}
+
+/*
+**************************************************************************************************************
+*                                     PROCESS TRANSFER DESCRIPTOR
+*
+* Description: This function processes the transfer descriptor
+*
+* Arguments  : ed            Endpoint descriptor that contains this transfer descriptor
+*              token         SETUP, IN, OUT
+*              buffer        Current Buffer Pointer of the transfer descriptor
+*              buffer_len    Length of the buffer
+*
+* Returns    : OK       if TD submission is successful
+*              ERROR    if TD submission fails
+*
+**************************************************************************************************************
+*/
+
+USB_INT32S  Host_ProcessTD (volatile  HCED       *ed,
+                            volatile  USB_INT32U  token,
+                            volatile  USB_INT08U *buffer,
+                                      USB_INT32U  buffer_len)
+{
+    volatile  USB_INT32U   td_toggle;
+
+
+    if (ed == EDCtrl) {
+        if (token == TD_SETUP) {
+            td_toggle = TD_TOGGLE_0;
+        } else {
+            td_toggle = TD_TOGGLE_1;
+        }
+    } else {
+        td_toggle = 0;
+    }
+    TDHead->Control = (TD_ROUNDING    |
+                      token           |
+                      TD_DELAY_INT(0) |                           
+                      td_toggle       |
+                      TD_CC);
+    TDTail->Control = 0;
+    TDHead->CurrBufPtr   = (USB_INT32U) buffer;
+    TDTail->CurrBufPtr   = 0;
+    TDHead->Next         = (USB_INT32U) TDTail;
+    TDTail->Next         = 0;
+    TDHead->BufEnd       = (USB_INT32U)(buffer + (buffer_len - 1));
+    TDTail->BufEnd       = 0;
+
+    ed->HeadTd  = (USB_INT32U)TDHead | ((ed->HeadTd) & 0x00000002);
+    ed->TailTd  = (USB_INT32U)TDTail;
+    ed->Next    = 0;
+
+    if (ed == EDCtrl) {
+        LPC_USB->HcControlHeadED = (USB_INT32U)ed;
+        LPC_USB->HcCommandStatus = LPC_USB->HcCommandStatus | OR_CMD_STATUS_CLF;
+        LPC_USB->HcControl       = LPC_USB->HcControl       | OR_CONTROL_CLE;
+    } else {
+        LPC_USB->HcBulkHeadED    = (USB_INT32U)ed;
+        LPC_USB->HcCommandStatus = LPC_USB->HcCommandStatus | OR_CMD_STATUS_BLF;
+        LPC_USB->HcControl       = LPC_USB->HcControl       | OR_CONTROL_BLE;
+    }    
+
+    Host_WDHWait();
+
+//    if (!(TDHead->Control & 0xF0000000)) {
+    if (!HOST_TDControlStatus) {
+        return (OK);
+    } else {      
+        return (ERR_TD_FAIL);
+    }
+}
+
+/*
+**************************************************************************************************************
+*                                       ENUMERATE THE DEVICE
+*
+* Description: This function is used to enumerate the device connected
+*
+* Arguments  : None
+*
+* Returns    : None
+*
+**************************************************************************************************************
+*/
+
+USB_INT32S  Host_EnumDev (void)
+{
+    USB_INT32S  rc;
+
+    //PRINT_Log("Connect a Mass Storage device\n");
+    while (!HOST_RhscIntr)
+        __WFI();
+    Host_DelayMS(100);                             /* USB 2.0 spec says atleast 50ms delay beore port reset */
+    LPC_USB->HcRhPortStatus1 = OR_RH_PORT_PRS; // Initiate port reset
+    while (LPC_USB->HcRhPortStatus1 & OR_RH_PORT_PRS)
+        __WFI(); // Wait for port reset to complete...
+    LPC_USB->HcRhPortStatus1 = OR_RH_PORT_PRSC; // ...and clear port reset signal
+    Host_DelayMS(200);                                                 /* Wait for 100 MS after port reset  */
+
+    EDCtrl->Control = 8 << 16;                                         /* Put max pkt size = 8              */
+                                                                       /* Read first 8 bytes of device desc */
+    rc = HOST_GET_DESCRIPTOR(USB_DESCRIPTOR_TYPE_DEVICE, 0, TDBuffer, 8);
+    if (rc != OK) {
+        PRINT_Err(rc);
+        return (rc);
+    }
+    EDCtrl->Control = TDBuffer[7] << 16;                               /* Get max pkt size of endpoint 0    */
+    rc = HOST_SET_ADDRESS(1);                                          /* Set the device address to 1       */
+    if (rc != OK) {
+        PRINT_Err(rc);
+        return (rc);
+    }
+    Host_DelayMS(2);
+    EDCtrl->Control = (EDCtrl->Control) | 1;                          /* Modify control pipe with address 1 */
+                                                                      /* Get the configuration descriptor   */
+    rc = HOST_GET_DESCRIPTOR(USB_DESCRIPTOR_TYPE_CONFIGURATION, 0, TDBuffer, 9);
+    if (rc != OK) {
+        PRINT_Err(rc);
+        return (rc);
+    }
+                                                                       /* Get the first configuration data  */
+    rc = HOST_GET_DESCRIPTOR(USB_DESCRIPTOR_TYPE_CONFIGURATION, 0, TDBuffer, ReadLE16U(&TDBuffer[2]));
+    if (rc != OK) {
+        PRINT_Err(rc);
+        return (rc);
+    }
+    //rc = MS_ParseConfiguration();                                      /* Parse the configuration           */
+    //if (rc != OK) {
+    //    PRINT_Err(rc);
+    //}
+    rc = USBH_SET_CONFIGURATION(1);                                    /* Select device configuration 1     */
+    if (rc != OK) {
+        PRINT_Err(rc);
+    }
+    Host_DelayMS(100);                                               /* Some devices may require this delay */
+    return (rc);
+}
+
+/*
+**************************************************************************************************************
+*                                        RECEIVE THE CONTROL INFORMATION
+*
+* Description: This function is used to receive the control information
+*
+* Arguments  : bm_request_type
+*              b_request
+*              w_value
+*              w_index
+*              w_length
+*              buffer
+*
+* Returns    : OK       if Success
+*              ERROR    if Failed
+*
+**************************************************************************************************************
+*/
+   
+USB_INT32S  Host_CtrlRecv (         USB_INT08U   bm_request_type,
+                                    USB_INT08U   b_request,
+                                    USB_INT16U   w_value,
+                                    USB_INT16U   w_index,
+                                    USB_INT16U   w_length,
+                          volatile  USB_INT08U  *buffer)
+{
+    USB_INT32S  rc;
+
+
+    Host_FillSetup(bm_request_type, b_request, w_value, w_index, w_length);
+    rc = Host_ProcessTD(EDCtrl, TD_SETUP, TDBuffer, 8);
+    if (rc == OK) {
+        if (w_length) {
+            rc = Host_ProcessTD(EDCtrl, TD_IN, buffer, w_length);
+        }
+        if (rc == OK) {
+            rc = Host_ProcessTD(EDCtrl, TD_OUT, NULL, 0);
+        }
+    }
+    return (rc);
+}
+
+/*
+**************************************************************************************************************
+*                                         SEND THE CONTROL INFORMATION
+*
+* Description: This function is used to send the control information
+*
+* Arguments  : None
+*
+* Returns    : OK                      if Success
+*              ERR_INVALID_BOOTSIG    if Failed
+*
+**************************************************************************************************************
+*/
+
+USB_INT32S  Host_CtrlSend (          USB_INT08U   bm_request_type,
+                                     USB_INT08U   b_request,
+                                     USB_INT16U   w_value,
+                                     USB_INT16U   w_index,
+                                     USB_INT16U   w_length,
+                           volatile  USB_INT08U  *buffer)
+{
+    USB_INT32S  rc;
+
+
+    Host_FillSetup(bm_request_type, b_request, w_value, w_index, w_length);
+
+    rc = Host_ProcessTD(EDCtrl, TD_SETUP, TDBuffer, 8);
+    if (rc == OK) {
+        if (w_length) {
+            rc = Host_ProcessTD(EDCtrl, TD_OUT, buffer, w_length);
+        }
+        if (rc == OK) {
+            rc = Host_ProcessTD(EDCtrl, TD_IN, NULL, 0);
+        }
+    }
+    return (rc);
+}
+
+/*
+**************************************************************************************************************
+*                                          FILL SETUP PACKET
+*
+* Description: This function is used to fill the setup packet
+*
+* Arguments  : None
+*
+* Returns    : OK                      if Success
+*              ERR_INVALID_BOOTSIG    if Failed
+*
+**************************************************************************************************************
+*/
+
+void  Host_FillSetup (USB_INT08U   bm_request_type,
+                      USB_INT08U   b_request,
+                      USB_INT16U   w_value,
+                      USB_INT16U   w_index,
+                      USB_INT16U   w_length)
+{
+    int i;
+    for (i=0;i<w_length;i++)
+        TDBuffer[i] = 0;
+    
+    TDBuffer[0] = bm_request_type;
+    TDBuffer[1] = b_request;
+    WriteLE16U(&TDBuffer[2], w_value);
+    WriteLE16U(&TDBuffer[4], w_index);
+    WriteLE16U(&TDBuffer[6], w_length);
+}
+
+
+
+/*
+**************************************************************************************************************
+*                                         INITIALIZE THE TRANSFER DESCRIPTOR
+*
+* Description: This function initializes transfer descriptor
+*
+* Arguments  : Pointer to TD structure
+*
+* Returns    : None
+*
+**************************************************************************************************************
+*/
+
+void  Host_TDInit (volatile  HCTD *td)
+{
+
+    td->Control    = 0;
+    td->CurrBufPtr = 0;
+    td->Next       = 0;
+    td->BufEnd     = 0;
+}
+
+/*
+**************************************************************************************************************
+*                                         INITIALIZE THE ENDPOINT DESCRIPTOR
+*
+* Description: This function initializes endpoint descriptor
+*
+* Arguments  : Pointer to ED strcuture
+*
+* Returns    : None
+*
+**************************************************************************************************************
+*/
+
+void  Host_EDInit (volatile  HCED *ed)
+{
+
+    ed->Control = 0;
+    ed->TailTd  = 0;
+    ed->HeadTd  = 0;
+    ed->Next    = 0;
+}
+
+/*
+**************************************************************************************************************
+*                                 INITIALIZE HOST CONTROLLER COMMUNICATIONS AREA
+*
+* Description: This function initializes host controller communications area
+*
+* Arguments  : Pointer to HCCA
+*
+* Returns    : 
+*
+**************************************************************************************************************
+*/
+
+void  Host_HCCAInit (volatile  HCCA  *hcca)
+{
+    USB_INT32U  i;
+
+
+    for (i = 0; i < 32; i++) {
+
+        hcca->IntTable[i] = 0;
+        hcca->FrameNumber = 0;
+        hcca->DoneHead    = 0;
+    }
+
+}
+
+/*
+**************************************************************************************************************
+*                                         WAIT FOR WDH INTERRUPT
+*
+* Description: This function is infinite loop which breaks when ever a WDH interrupt rises
+*
+* Arguments  : None
+*
+* Returns    : None
+*
+**************************************************************************************************************
+*/
+
+void  Host_WDHWait (void)
+{
+  while (!HOST_WdhIntr)
+      __WFI();
+
+  HOST_WdhIntr = 0;
+}
+
+/*
+**************************************************************************************************************
+*                                         READ LE 32U
+*
+* Description: This function is used to read an unsigned integer from a character buffer in the platform
+*              containing little endian processor
+*
+* Arguments  : pmem    Pointer to the character buffer
+*
+* Returns    : val     Unsigned integer
+*
+**************************************************************************************************************
+*/
+
+USB_INT32U  ReadLE32U (volatile  USB_INT08U  *pmem)
+{
+    USB_INT32U val = *(USB_INT32U*)pmem;
+#ifdef __BIG_ENDIAN
+    return __REV(val);
+#else
+    return val;
+#endif    
+}
+
+/*
+**************************************************************************************************************
+*                                        WRITE LE 32U
+*
+* Description: This function is used to write an unsigned integer into a charecter buffer in the platform 
+*              containing little endian processor.
+*
+* Arguments  : pmem    Pointer to the charecter buffer
+*              val     Integer value to be placed in the charecter buffer
+*
+* Returns    : None
+*
+**************************************************************************************************************
+*/
+
+void  WriteLE32U (volatile  USB_INT08U  *pmem,
+                            USB_INT32U   val)
+{
+#ifdef __BIG_ENDIAN
+    *(USB_INT32U*)pmem = __REV(val);
+#else
+    *(USB_INT32U*)pmem = val;
+#endif
+}
+
+/*
+**************************************************************************************************************
+*                                          READ LE 16U
+*
+* Description: This function is used to read an unsigned short integer from a charecter buffer in the platform
+*              containing little endian processor
+*
+* Arguments  : pmem    Pointer to the charecter buffer
+*
+* Returns    : val     Unsigned short integer
+*
+**************************************************************************************************************
+*/
+
+USB_INT16U  ReadLE16U (volatile  USB_INT08U  *pmem)
+{
+    USB_INT16U val = *(USB_INT16U*)pmem;
+#ifdef __BIG_ENDIAN
+    return __REV16(val);
+#else
+    return val;
+#endif    
+}
+
+/*
+**************************************************************************************************************
+*                                         WRITE LE 16U
+*
+* Description: This function is used to write an unsigned short integer into a charecter buffer in the
+*              platform containing little endian processor
+*
+* Arguments  : pmem    Pointer to the charecter buffer
+*              val     Value to be placed in the charecter buffer
+*
+* Returns    : None
+*
+**************************************************************************************************************
+*/
+
+void  WriteLE16U (volatile  USB_INT08U  *pmem,
+                            USB_INT16U   val)
+{
+#ifdef __BIG_ENDIAN
+    *(USB_INT16U*)pmem = (__REV16(val) & 0xFFFF);
+#else
+    *(USB_INT16U*)pmem = val;
+#endif
+}
+
+/*
+**************************************************************************************************************
+*                                         READ BE 32U
+*
+* Description: This function is used to read an unsigned integer from a charecter buffer in the platform
+*              containing big endian processor
+*
+* Arguments  : pmem    Pointer to the charecter buffer
+*
+* Returns    : val     Unsigned integer
+*
+**************************************************************************************************************
+*/
+
+USB_INT32U  ReadBE32U (volatile  USB_INT08U  *pmem)
+{
+    USB_INT32U val = *(USB_INT32U*)pmem;
+#ifdef __BIG_ENDIAN
+    return val;
+#else
+    return __REV(val);
+#endif
+}
+
+/*
+**************************************************************************************************************
+*                                         WRITE BE 32U
+*
+* Description: This function is used to write an unsigned integer into a charecter buffer in the platform
+*              containing big endian processor
+*
+* Arguments  : pmem    Pointer to the charecter buffer
+*              val     Value to be placed in the charecter buffer
+*
+* Returns    : None
+*
+**************************************************************************************************************
+*/
+
+void  WriteBE32U (volatile  USB_INT08U  *pmem,
+                            USB_INT32U   val)
+{
+#ifdef __BIG_ENDIAN
+    *(USB_INT32U*)pmem = val;
+#else
+    *(USB_INT32U*)pmem = __REV(val);
+#endif
+}
+
+/*
+**************************************************************************************************************
+*                                         READ BE 16U
+*
+* Description: This function is used to read an unsigned short integer from a charecter buffer in the platform
+*              containing big endian processor
+*
+* Arguments  : pmem    Pointer to the charecter buffer
+*
+* Returns    : val     Unsigned short integer
+*
+**************************************************************************************************************
+*/
+
+USB_INT16U  ReadBE16U (volatile  USB_INT08U  *pmem)
+{
+    USB_INT16U val = *(USB_INT16U*)pmem;
+#ifdef __BIG_ENDIAN
+    return val;
+#else
+    return __REV16(val);
+#endif    
+}
+
+/*
+**************************************************************************************************************
+*                                         WRITE BE 16U
+*
+* Description: This function is used to write an unsigned short integer into the charecter buffer in the
+*              platform containing big endian processor
+*
+* Arguments  : pmem    Pointer to the charecter buffer
+*              val     Value to be placed in the charecter buffer
+*
+* Returns    : None
+*
+**************************************************************************************************************
+*/
+
+void  WriteBE16U (volatile  USB_INT08U  *pmem,
+                            USB_INT16U   val)
+{
+#ifdef __BIG_ENDIAN
+    *(USB_INT16U*)pmem = val;
+#else
+    *(USB_INT16U*)pmem = (__REV16(val) & 0xFFFF);
+#endif
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/USBHostLite/usbhost_lpc17xx.h	Mon Apr 30 14:24:46 2012 +0000
@@ -0,0 +1,254 @@
+/*
+**************************************************************************************************************
+*                                                 NXP USB Host Stack
+*
+*                                     (c) Copyright 2008, NXP SemiConductors
+*                                     (c) Copyright 2008, OnChip  Technologies LLC
+*                                                 All Rights Reserved
+*
+*                                                  www.nxp.com
+*                                               www.onchiptech.com
+*
+* File           : usbhost_lpc17xx.h
+* Programmer(s)  : Ravikanth.P
+* Version        :
+*
+**************************************************************************************************************
+*/
+
+#ifndef USBHOST_LPC17xx_H
+#define USBHOST_LPC17xx_H
+
+/*
+**************************************************************************************************************
+*                                       INCLUDE HEADER FILES
+**************************************************************************************************************
+*/
+
+#include    "usbhost_inc.h"
+
+/*
+**************************************************************************************************************
+*                                        PRINT CONFIGURATION
+**************************************************************************************************************
+*/
+
+#define  PRINT_ENABLE         1
+
+#if PRINT_ENABLE
+#define  PRINT_Log(...)       fprintf(stderr,__VA_ARGS__)
+#define  PRINT_Err(rc)        fprintf(stderr,"ERROR: In %s at Line %u - rc = %d\n", __FUNCTION__, __LINE__, rc)
+
+#else 
+#define  PRINT_Log(...)       do {} while(0)
+#define  PRINT_Err(rc)        do {} while(0)
+
+#endif
+
+/*
+**************************************************************************************************************
+*                                        GENERAL DEFINITIONS
+**************************************************************************************************************
+*/
+
+#define  DESC_LENGTH(x)  x[0]
+#define  DESC_TYPE(x)    x[1]
+
+
+#define  HOST_GET_DESCRIPTOR(descType, descIndex, data, length)                      \
+         Host_CtrlRecv(USB_DEVICE_TO_HOST | USB_RECIPIENT_DEVICE, GET_DESCRIPTOR,    \
+         (descType << 8)|(descIndex), 0, length, data)
+
+#define  HOST_SET_ADDRESS(new_addr)                                                  \
+         Host_CtrlSend(USB_HOST_TO_DEVICE | USB_RECIPIENT_DEVICE, SET_ADDRESS,       \
+         new_addr, 0, 0, NULL)
+
+#define  USBH_SET_CONFIGURATION(configNum)                                           \
+         Host_CtrlSend(USB_HOST_TO_DEVICE | USB_RECIPIENT_DEVICE, SET_CONFIGURATION, \
+         configNum, 0, 0, NULL)
+
+#define  USBH_SET_INTERFACE(ifNum, altNum)                                           \
+         Host_CtrlSend(USB_HOST_TO_DEVICE | USB_RECIPIENT_INTERFACE, SET_INTERFACE,  \
+         altNum, ifNum, 0, NULL)
+
+/*
+**************************************************************************************************************
+*                                  OHCI OPERATIONAL REGISTER FIELD DEFINITIONS
+**************************************************************************************************************
+*/
+
+                                            /* ------------------ HcControl Register ---------------------  */
+#define  OR_CONTROL_CLE                 0x00000010
+#define  OR_CONTROL_BLE                 0x00000020
+#define  OR_CONTROL_HCFS                0x000000C0
+#define  OR_CONTROL_HC_OPER             0x00000080
+                                            /* ----------------- HcCommandStatus Register ----------------- */
+#define  OR_CMD_STATUS_HCR              0x00000001
+#define  OR_CMD_STATUS_CLF              0x00000002
+#define  OR_CMD_STATUS_BLF              0x00000004
+                                            /* --------------- HcInterruptStatus Register ----------------- */
+#define  OR_INTR_STATUS_WDH             0x00000002
+#define  OR_INTR_STATUS_RHSC            0x00000040
+                                            /* --------------- HcInterruptEnable Register ----------------- */
+#define  OR_INTR_ENABLE_WDH             0x00000002
+#define  OR_INTR_ENABLE_RHSC            0x00000040
+#define  OR_INTR_ENABLE_MIE             0x80000000
+                                            /* ---------------- HcRhDescriptorA Register ------------------ */
+#define  OR_RH_STATUS_LPSC              0x00010000
+#define  OR_RH_STATUS_DRWE              0x00008000
+                                            /* -------------- HcRhPortStatus[1:NDP] Register -------------- */
+#define  OR_RH_PORT_CCS                 0x00000001
+#define  OR_RH_PORT_PRS                 0x00000010
+#define  OR_RH_PORT_CSC                 0x00010000
+#define  OR_RH_PORT_PRSC                0x00100000
+
+
+/*
+**************************************************************************************************************
+*                                               FRAME INTERVAL
+**************************************************************************************************************
+*/
+
+#define  FI                     0x2EDF           /* 12000 bits per frame (-1)                               */
+#define  DEFAULT_FMINTERVAL     ((((6 * (FI - 210)) / 7) << 16) | FI)
+
+/*
+**************************************************************************************************************
+*                                       TRANSFER DESCRIPTOR CONTROL FIELDS
+**************************************************************************************************************
+*/
+
+#define  TD_ROUNDING        (USB_INT32U) (0x00040000)        /* Buffer Rounding                             */
+#define  TD_SETUP           (USB_INT32U)(0)                  /* Direction of Setup Packet                   */
+#define  TD_IN              (USB_INT32U)(0x00100000)         /* Direction In                                */
+#define  TD_OUT             (USB_INT32U)(0x00080000)         /* Direction Out                               */
+#define  TD_DELAY_INT(x)    (USB_INT32U)((x) << 21)          /* Delay Interrupt                             */
+#define  TD_TOGGLE_0        (USB_INT32U)(0x02000000)         /* Toggle 0                                    */
+#define  TD_TOGGLE_1        (USB_INT32U)(0x03000000)         /* Toggle 1                                    */
+#define  TD_CC              (USB_INT32U)(0xF0000000)         /* Completion Code                             */
+
+/*
+**************************************************************************************************************
+*                                       USB STANDARD REQUEST DEFINITIONS
+**************************************************************************************************************
+*/
+
+#define  USB_DESCRIPTOR_TYPE_DEVICE                     1
+#define  USB_DESCRIPTOR_TYPE_CONFIGURATION              2
+#define  USB_DESCRIPTOR_TYPE_INTERFACE                  4
+#define  USB_DESCRIPTOR_TYPE_ENDPOINT                   5
+                                                    /*  ----------- Control RequestType Fields  ----------- */
+#define  USB_DEVICE_TO_HOST         0x80
+#define  USB_HOST_TO_DEVICE         0x00
+#define  USB_REQUEST_TYPE_CLASS     0x20
+#define  USB_RECIPIENT_DEVICE       0x00
+#define  USB_RECIPIENT_INTERFACE    0x01
+                                                    /* -------------- USB Standard Requests  -------------- */
+#define  SET_ADDRESS                 5
+#define  GET_DESCRIPTOR              6
+#define  SET_CONFIGURATION           9
+#define  SET_INTERFACE              11
+
+/*
+**************************************************************************************************************
+*                                       TYPE DEFINITIONS
+**************************************************************************************************************
+*/
+
+typedef struct hcEd {                       /* ----------- HostController EndPoint Descriptor ------------- */
+    volatile  USB_INT32U  Control;              /* Endpoint descriptor control                              */
+    volatile  USB_INT32U  TailTd;               /* Physical address of tail in Transfer descriptor list     */
+    volatile  USB_INT32U  HeadTd;               /* Physcial address of head in Transfer descriptor list     */
+    volatile  USB_INT32U  Next;                 /* Physical address of next Endpoint descriptor             */
+} HCED;
+
+typedef struct hcTd {                       /* ------------ HostController Transfer Descriptor ------------ */
+    volatile  USB_INT32U  Control;              /* Transfer descriptor control                              */
+    volatile  USB_INT32U  CurrBufPtr;           /* Physical address of current buffer pointer               */
+    volatile  USB_INT32U  Next;                 /* Physical pointer to next Transfer Descriptor             */
+    volatile  USB_INT32U  BufEnd;               /* Physical address of end of buffer                        */
+} HCTD;
+
+typedef struct hcca {                       /* ----------- Host Controller Communication Area ------------  */
+    volatile  USB_INT32U  IntTable[32];         /* Interrupt Table                                          */
+    volatile  USB_INT32U  FrameNumber;          /* Frame Number                                             */
+    volatile  USB_INT32U  DoneHead;             /* Done Head                                                */
+    volatile  USB_INT08U  Reserved[116];        /* Reserved for future use                                  */
+    volatile  USB_INT08U  Unknown[4];           /* Unused                                                   */
+} HCCA;
+
+/*
+**************************************************************************************************************
+*                                     EXTERN DECLARATIONS
+**************************************************************************************************************
+*/
+
+extern  volatile  HCED        *EDBulkIn;        /* BulkIn endpoint descriptor  structure                    */
+extern  volatile  HCED        *EDBulkOut;       /* BulkOut endpoint descriptor structure                    */
+extern  volatile  HCTD        *TDHead;          /* Head transfer descriptor structure                       */
+extern  volatile  HCTD        *TDTail;          /* Tail transfer descriptor structure                       */
+extern  volatile  USB_INT08U  *TDBuffer;        /* Current Buffer Pointer of transfer descriptor            */
+
+/*
+**************************************************************************************************************
+*                                       FUNCTION PROTOTYPES
+**************************************************************************************************************
+*/
+
+void        Host_Init     (void);
+
+extern "C" void USB_IRQHandler(void)  __irq;
+
+USB_INT32S  Host_EnumDev  (void);
+
+USB_INT32S  Host_ProcessTD(volatile  HCED       *ed,
+                           volatile  USB_INT32U  token,
+                           volatile  USB_INT08U *buffer,
+                                     USB_INT32U  buffer_len);
+
+void        Host_DelayUS  (          USB_INT32U    delay);
+void        Host_DelayMS  (          USB_INT32U    delay);
+
+
+void        Host_TDInit   (volatile  HCTD *td);
+void        Host_EDInit   (volatile  HCED *ed);
+void        Host_HCCAInit (volatile  HCCA  *hcca);
+
+USB_INT32S  Host_CtrlRecv (          USB_INT08U   bm_request_type,
+                                     USB_INT08U   b_request,
+                                     USB_INT16U   w_value,
+                                     USB_INT16U   w_index,
+                                     USB_INT16U   w_length,
+                           volatile  USB_INT08U  *buffer);
+
+USB_INT32S  Host_CtrlSend (          USB_INT08U   bm_request_type,
+                                     USB_INT08U   b_request,
+                                     USB_INT16U   w_value,
+                                     USB_INT16U   w_index,
+                                     USB_INT16U   w_length,
+                           volatile  USB_INT08U  *buffer);
+
+void        Host_FillSetup(          USB_INT08U   bm_request_type,
+                                     USB_INT08U   b_request,
+                                     USB_INT16U   w_value,
+                                     USB_INT16U   w_index,
+                                     USB_INT16U   w_length);
+
+
+void        Host_WDHWait  (void);
+
+
+USB_INT32U  ReadLE32U     (volatile  USB_INT08U  *pmem);
+void        WriteLE32U    (volatile  USB_INT08U  *pmem,
+                                     USB_INT32U   val);
+USB_INT16U  ReadLE16U     (volatile  USB_INT08U  *pmem);
+void        WriteLE16U    (volatile  USB_INT08U  *pmem,
+                                     USB_INT16U   val);
+USB_INT32U  ReadBE32U     (volatile  USB_INT08U  *pmem);
+void        WriteBE32U    (volatile  USB_INT08U  *pmem,
+                                     USB_INT32U   val);
+USB_INT16U  ReadBE16U     (volatile  USB_INT08U  *pmem);
+void        WriteBE16U    (volatile  USB_INT08U  *pmem,
+                                     USB_INT16U   val);
+
+#endif
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Mon Apr 30 14:24:46 2012 +0000
@@ -0,0 +1,17 @@
+#include "mbed.h"
+#include "usbgps.h"
+
+Serial pc(USBTX, USBRX);
+
+int main()
+{
+    pc.baud(460800);
+    
+    usbgps gps;
+    while(1) {
+        if (gps.readable()) {
+            int c = gps.getc();
+            printf("%c", c);
+        }
+    }
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Mon Apr 30 14:24:46 2012 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/49a220cc26e0
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/usbgps.cpp	Mon Apr 30 14:24:46 2012 +0000
@@ -0,0 +1,106 @@
+#include "mbed.h"
+#include "usbgps.h"
+
+#define PL2303_SET_LINE_CODING 0x20
+
+usbgps::usbgps()
+{
+    m_init = false;
+    m_connect = false;
+}
+
+int usbgps::readable()
+{
+    if (!m_init) {
+        _init();
+    }
+    for(int i = 0; i < 2; i++) {
+        if (!_receive.empty()) {
+            return 1;
+        }
+        _receive_proc();
+    }
+    return 0;
+}
+
+void usbgps::_init()
+{
+    m_init = true;
+    Host_Init();               /* Initialize the  host controller                                    */
+    USB_INT32S rc = Host_EnumDev(); /* Enumerate the device connected                                            */
+    if (rc != OK) {
+        PRINT_Log("Could not enumerate device: %d\n", rc);
+        return;
+    }
+    rc = HOST_GET_DESCRIPTOR(USB_DESCRIPTOR_TYPE_DEVICE, 0, TDBuffer, 18);
+    if (rc != OK) {
+        PRINT_Err(rc);
+        return;
+    }
+    if (0x067b == ReadLE16U(TDBuffer+8) && // Vender ID 067Bh
+        0x2303 == ReadLE16U(TDBuffer+10)) { // Product ID 2303h
+        PRINT_Log("GT-730F/L GPS USB Dongle connected\n");
+    } else {
+        PRINT_Log("not gps usb\n");
+        return;
+    }
+    EDBulkIn->Control =  1                    |      /* USB address           */
+                         ((0x83 & 0x7F) << 7) |      /* Endpoint address      */
+                         (2 << 11)            |      /* direction             */
+                         (64 << 16);                 /* MaxPkt Size           */
+
+    const USB_INT08U data[] = {0x00, 0x96, 0x00, 0x00, 0x00, 0x00, 0x08}; // default 38400bps,8bit
+    rc = Host_CtrlSend(USB_HOST_TO_DEVICE | USB_REQUEST_TYPE_CLASS | USB_RECIPIENT_INTERFACE, 
+                       PL2303_SET_LINE_CODING, 0, 0, sizeof(data), (USB_INT08U*)data);
+    if (rc != OK) {
+        PRINT_Err(rc);
+        return;
+    }
+    USB_INT08U temp[7];
+    rc = Host_CtrlRecv(USB_DEVICE_TO_HOST | USB_REQUEST_TYPE_CLASS | USB_RECIPIENT_INTERFACE, 
+                       0x21, 0, 0, sizeof(temp), temp);
+    if (rc != OK) {
+        PRINT_Err(rc);
+        return;
+    }
+    m_connect = true;
+}
+
+void usbgps::_receive_proc()
+{
+    if (!m_connect) {
+        return;
+    }
+    USB_INT08U buf[64];
+    USB_INT32S rc = Host_ProcessTD(EDBulkIn, TD_IN, buf, sizeof(buf));
+    if (rc == OK) {
+        int len = 0;
+        if (TDHead->CurrBufPtr) {
+            len = TDHead->CurrBufPtr - (int)buf;
+        }
+        for(int i = 0; i < len; i++) {
+            _receive.push(buf[i]);
+        }
+    }
+}
+
+int usbgps::_getc()
+{
+    if (!m_init) {
+        _init();
+    }
+    for(int i = 0; i < 2; i++) {
+        if (!_receive.empty()) {
+            int c = _receive.front();
+            _receive.pop();
+            return c;
+        }
+        _receive_proc();
+    }
+    return -1;
+}
+
+int usbgps::_putc(int c)
+{
+    return c;
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/usbgps.h	Mon Apr 30 14:24:46 2012 +0000
@@ -0,0 +1,20 @@
+#ifndef USBGPS_H
+#define USBGPS_H
+#include "usbhost_cpu.h"
+#include "usbhost_lpc17xx.h"
+#include <queue>
+
+class usbgps : public Stream {
+public:
+    usbgps();
+    int readable();
+protected:
+    void _init();
+    void _receive_proc();
+    virtual int _getc();
+    virtual int _putc(int c);
+    queue<char> _receive;
+    bool m_connect;
+    bool m_init;
+};
+#endif //USBGPS_H
\ No newline at end of file