Diff: targets/hal/TARGET_Atmel/TARGET_SAM21/serial_api.c

Revision:

613:bc40b8d2aec4

Parent:

612:fba1c7dc54c0

Child:

614:9d86c2ae5de0

--- a/targets/hal/TARGET_Atmel/TARGET_SAM21/serial_api.c	Tue Aug 18 15:00:09 2015 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,1032 +0,0 @@
-/* mbed Microcontroller Library
- * Copyright (c) 2006-2013 ARM Limited
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-#include <string.h>
-#include "mbed_assert.h"
-#include "cmsis.h"
-#include "serial_api.h"
-#include "pinmap.h"
-#include "PeripheralPins.h"
-#include "usart.h"
-#include "pinmap_function.h"
-
-#define USART_TX_INDEX		0
-#define USART_RX_INDEX		1
-#define USART_RXFLOW_INDEX	2
-#define USART_TXFLOW_INDEX	3
-
-#if DEVICE_SERIAL_ASYNCH
-#define pUSART_S(obj)			obj->serial.usart
-#define pSERIAL_S(obj)			((struct serial_s*)&(obj->serial))
-#else
-#define pUSART_S(obj)			obj->serial
-#define pSERIAL_S(obj)			((struct serial_s*)obj)
-#endif
-#define _USART(obj)			pUSART_S(obj)->USART
-#define USART_NUM 6
-
-
-uint8_t serial_get_index(serial_t *obj);
-IRQn_Type get_serial_irq_num (serial_t *obj);
-uint32_t get_serial_vector (serial_t *obj);
-void uart0_irq();
-void uart1_irq();
-void uart2_irq();
-void uart3_irq();
-void uart4_irq();
-void uart5_irq();
-
-static uint32_t serial_irq_ids[USART_NUM] = {0};
-static uart_irq_handler irq_handler;
-
-int stdio_uart_inited = 0;
-serial_t stdio_uart;
-
-extern uint8_t g_sys_init;
-
-static inline bool usart_syncing(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-
-    return (_USART(obj).SYNCBUSY.reg);
-}
-
-static inline void enable_usart(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-
-    /* Wait until synchronization is complete */
-    usart_syncing(obj);
-
-    /* Enable USART module */
-    _USART(obj).CTRLA.reg |= SERCOM_USART_CTRLA_ENABLE;
-}
-
-static inline void disable_usart(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-
-    /* Wait until synchronization is complete */
-    usart_syncing(obj);
-
-    /* Disable USART module */
-    _USART(obj).CTRLA.reg &= ~SERCOM_USART_CTRLA_ENABLE;
-}
-
-static inline void reset_usart(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-
-    disable_usart(obj);
-
-    /* Wait until synchronization is complete */
-    usart_syncing(obj);
-
-    /* Reset module */
-    _USART(obj).CTRLA.reg = SERCOM_USART_CTRLA_SWRST;
-}
-
-uint32_t serial_find_mux_settings (serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    uint32_t mux_setting = 0;
-    uint32_t pinpad[4] = {0};
-    uint8_t i = 0;
-    uint32_t sercom_index = pinmap_merge_sercom(pSERIAL_S(obj)->pins[0], pSERIAL_S(obj)->pins[1]);
-
-    for (i = 0; i < 4 ; i++) {
-        pinpad[i] = pinmap_pad_sercom(pSERIAL_S(obj)->pins[i], sercom_index);
-    }
-
-    switch(pinpad[USART_RX_INDEX]) {
-        case 0:
-            mux_setting |= SERCOM_USART_CTRLA_RXPO(0);
-            break;
-        case 1:
-            mux_setting |= SERCOM_USART_CTRLA_RXPO(1);
-            break;
-        case 2:
-            mux_setting |= SERCOM_USART_CTRLA_RXPO(2);
-            break;
-        case 3:
-            mux_setting |= SERCOM_USART_CTRLA_RXPO(3);
-            break;
-    }
-
-    if ((pSERIAL_S(obj)->pins[USART_RXFLOW_INDEX] == NC) && (pSERIAL_S(obj)->pins[USART_TXFLOW_INDEX] == NC)) {
-        if (pinpad[USART_TX_INDEX] == 0) {
-            mux_setting |= SERCOM_USART_CTRLA_TXPO(0);
-        } else if(pinpad[USART_RX_INDEX] == 2) {
-            mux_setting |= SERCOM_USART_CTRLA_TXPO(1);
-        } else {
-            mux_setting = mux_setting;  // dummy condition
-        }
-    } else { // for hardware flow control and uart // expecting the tx in pad 0, rts in pad2 and cts in pad 3
-        if((pinpad[USART_TX_INDEX] == 0) && (pinpad[USART_RXFLOW_INDEX]/*rts pin*/ == 2) && (pinpad[USART_TXFLOW_INDEX] /*cts pin*/ == 3)) {
-            mux_setting |= SERCOM_USART_CTRLA_TXPO(2);
-        }
-    }
-    return mux_setting;
-}
-
-static enum status_code usart_set_config_default(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    /* Index for generic clock */
-    uint32_t sercom_index = _sercom_get_sercom_inst_index(pUSART_S(obj));
-    uint32_t gclk_index   = sercom_index + SERCOM0_GCLK_ID_CORE;
-
-    /* Cache new register values to minimize the number of register writes */
-    uint32_t ctrla = 0;
-    uint32_t ctrlb = 0;
-    uint16_t baud  = 0;
-
-    enum sercom_asynchronous_operation_mode mode = SERCOM_ASYNC_OPERATION_MODE_ARITHMETIC;
-    enum sercom_asynchronous_sample_num sample_num = SERCOM_ASYNC_SAMPLE_NUM_16;
-
-    /* Set data order, internal muxing, and clock polarity */
-    ctrla = (uint32_t)USART_DATAORDER_LSB |         // data order
-            (uint32_t)pSERIAL_S(obj)->mux_setting;  // mux setting  // clock polarity is not used
-
-
-    /* Get baud value from mode and clock */
-    _sercom_get_async_baud_val(pSERIAL_S(obj)->baudrate,system_gclk_chan_get_hz(gclk_index), &baud, mode, sample_num);  // for asynchronous transfer mode
-
-    /* Wait until synchronization is complete */
-    usart_syncing(obj);
-
-    /*Set baud val */
-    _USART(obj).BAUD.reg = baud;
-
-    /* Set sample mode */
-    ctrla |= USART_TRANSFER_ASYNCHRONOUSLY;
-
-    /* for disabled external clock source */
-    ctrla |= SERCOM_USART_CTRLA_MODE(0x1);
-
-    /* Set stopbits, character size and enable transceivers */
-    ctrlb = (uint32_t)pSERIAL_S(obj)->stopbits | (uint32_t)pSERIAL_S(obj)->character_size |
-            (0x1ul << SERCOM_USART_CTRLB_RXEN_Pos) |   // receiver enable
-            (0x1ul << SERCOM_USART_CTRLB_TXEN_Pos);  // transmitter enable
-
-    /* Check parity mode bits */
-    if (pSERIAL_S(obj)->parity != USART_PARITY_NONE) {
-        ctrla |= SERCOM_USART_CTRLA_FORM(1);
-        ctrlb |= pSERIAL_S(obj)->parity;
-    } else {
-        ctrla |= SERCOM_USART_CTRLA_FORM(0);
-    }
-
-    /* Wait until synchronization is complete */
-    usart_syncing(obj);
-
-    /* Write configuration to CTRLB */
-    _USART(obj).CTRLB.reg = ctrlb;
-
-    /* Wait until synchronization is complete */
-    usart_syncing(obj);
-
-    /* Write configuration to CTRLA */
-    _USART(obj).CTRLA.reg = ctrla;
-
-    return STATUS_OK;
-}
-
-void get_default_serial_values(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    /* Set default config to object */
-    pSERIAL_S(obj)->parity = USART_PARITY_NONE;
-    pSERIAL_S(obj)->stopbits = USART_STOPBITS_1;
-    pSERIAL_S(obj)->character_size = USART_CHARACTER_SIZE_8BIT;
-    pSERIAL_S(obj)->baudrate = 9600;
-    pSERIAL_S(obj)->mux_setting = USART_RX_1_TX_2_XCK_3;
-};
-
-void serial_init(serial_t *obj, PinName tx, PinName rx)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    if (g_sys_init == 0) {
-        system_init();
-        g_sys_init = 1;
-    }
-    struct system_gclk_chan_config gclk_chan_conf;
-    UARTName uart;
-    uint32_t gclk_index;
-    uint32_t pm_index;
-    uint32_t sercom_index = 0;
-    uint32_t muxsetting = 0;
-
-    /* Disable USART module */
-    disable_usart(obj);
-
-    get_default_serial_values(obj);
-
-    pSERIAL_S(obj)->pins[USART_TX_INDEX] = tx;
-    pSERIAL_S(obj)->pins[USART_RX_INDEX] = rx;
-    pSERIAL_S(obj)->pins[USART_RXFLOW_INDEX] = NC;
-    pSERIAL_S(obj)->pins[USART_TXFLOW_INDEX] = NC;
-
-    muxsetting = serial_find_mux_settings(obj);  // getting mux setting from pins
-    sercom_index = pinmap_merge_sercom(tx, rx);  // same variable sercom_index reused for optimization
-    if (sercom_index == (uint32_t)NC) {
-        /*expecting a valid value for sercom index*/
-        return;
-    }
-    sercom_index &= 0x0F;
-    uart = pinmap_peripheral_sercom(NC, sercom_index);
-    pUSART_S(obj) = (Sercom *)uart;
-
-    pm_index     = sercom_index + PM_APBCMASK_SERCOM0_Pos;
-    gclk_index   = sercom_index + SERCOM0_GCLK_ID_CORE;
-
-    if (_USART(obj).CTRLA.reg & SERCOM_USART_CTRLA_SWRST) {
-        return;  /* The module is busy resetting itself */
-    }
-
-    if (_USART(obj).CTRLA.reg & SERCOM_USART_CTRLA_ENABLE) {
-        return;    /* Check the module is enabled */
-    }
-
-    /* Turn on module in PM */
-    system_apb_clock_set_mask(SYSTEM_CLOCK_APB_APBC, 1 << pm_index);
-
-    /* Set up the GCLK for the module */
-    gclk_chan_conf.source_generator = GCLK_GENERATOR_0;
-    system_gclk_chan_set_config(gclk_index, &gclk_chan_conf);
-    system_gclk_chan_enable(gclk_index);
-    sercom_set_gclk_generator(GCLK_GENERATOR_0, false);
-
-    pSERIAL_S(obj)->mux_setting = muxsetting;
-    /* Set configuration according to the config struct */
-    usart_set_config_default(obj);
-
-    struct system_pinmux_config pin_conf;
-    pin_conf.direction = SYSTEM_PINMUX_PIN_DIR_INPUT;
-    pin_conf.input_pull = SYSTEM_PINMUX_PIN_PULL_NONE;
-    pin_conf.powersave    = false;
-
-    /* Configure the SERCOM pins according to the user configuration */
-    for (uint8_t pad = 0; pad < 4; pad++) {
-        uint32_t current_pin = pSERIAL_S(obj)->pins[pad];
-        if (current_pin != (uint32_t)NC) {
-            pin_conf.mux_position = pinmap_function_sercom(current_pin, sercom_index);
-            if ((uint8_t)NC != pin_conf.mux_position) {
-                system_pinmux_pin_set_config(current_pin, &pin_conf);
-            }
-        }
-    }
-
-    if (uart == STDIO_UART) {
-        stdio_uart_inited = 1;
-        memcpy(&stdio_uart, obj, sizeof(serial_t));
-    }
-    /* Wait until synchronization is complete */
-    usart_syncing(obj);
-
-    /* Enable USART module */
-    enable_usart(obj);
-}
-
-void serial_free(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    serial_irq_ids[serial_get_index(obj)] = 0;
-    disable_usart(obj);
-}
-
-void serial_baud(serial_t *obj, int baudrate)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    MBED_ASSERT((baudrate == 110) || (baudrate == 150) || (baudrate == 300) || (baudrate == 1200) ||
-                (baudrate == 2400) || (baudrate == 4800) || (baudrate == 9600) || (baudrate == 19200) || (baudrate == 38400) ||
-                (baudrate == 57600) || (baudrate == 115200) || (baudrate == 230400) || (baudrate == 460800) || (baudrate == 921600) );
-
-    struct system_gclk_chan_config gclk_chan_conf;
-    uint32_t gclk_index;
-    uint16_t baud  = 0;
-    uint32_t sercom_index = 0;
-    enum sercom_asynchronous_operation_mode mode = SERCOM_ASYNC_OPERATION_MODE_ARITHMETIC;
-    enum sercom_asynchronous_sample_num sample_num = SERCOM_ASYNC_SAMPLE_NUM_16;
-
-    pSERIAL_S(obj)->baudrate = baudrate;
-    disable_usart(obj);
-
-    sercom_index = _sercom_get_sercom_inst_index(pUSART_S(obj));
-    gclk_index   = sercom_index + SERCOM0_GCLK_ID_CORE;
-
-    gclk_chan_conf.source_generator = GCLK_GENERATOR_0;
-    system_gclk_chan_set_config(gclk_index, &gclk_chan_conf);
-    system_gclk_chan_enable(gclk_index);
-    sercom_set_gclk_generator(GCLK_GENERATOR_0, false);
-
-    /* Get baud value from mode and clock */
-    _sercom_get_async_baud_val(pSERIAL_S(obj)->baudrate, system_gclk_chan_get_hz(gclk_index), &baud, mode, sample_num);
-
-    /* Wait until synchronization is complete */
-    usart_syncing(obj);
-
-    /*Set baud val */
-    _USART(obj).BAUD.reg = baud;
-    /* Wait until synchronization is complete */
-    usart_syncing(obj);
-
-    enable_usart(obj);
-}
-
-void serial_format(serial_t *obj, int data_bits, SerialParity parity, int stop_bits)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    MBED_ASSERT((stop_bits == 1) || (stop_bits == 2));
-    MBED_ASSERT((parity == ParityNone) || (parity == ParityOdd) || (parity == ParityEven));
-    MBED_ASSERT((data_bits == 5) || (data_bits == 6) || (data_bits == 7) || (data_bits == 8) /*|| (data_bits == 9)*/);
-
-    /* Cache new register values to minimize the number of register writes */
-    uint32_t ctrla = 0;
-    uint32_t ctrlb = 0;
-
-    disable_usart(obj);
-
-    ctrla = _USART(obj).CTRLA.reg;
-    ctrlb = _USART(obj).CTRLB.reg;
-
-    ctrla &= ~(SERCOM_USART_CTRLA_FORM_Msk);
-    ctrlb &= ~(SERCOM_USART_CTRLB_CHSIZE_Msk);
-    ctrlb &= ~(SERCOM_USART_CTRLB_SBMODE);
-    ctrlb &= ~(SERCOM_USART_CTRLB_PMODE);
-
-    switch (stop_bits) {
-        case 1:
-            pSERIAL_S(obj)->stopbits = USART_STOPBITS_1;
-            break;
-        case 2:
-            pSERIAL_S(obj)->stopbits = USART_STOPBITS_2;
-            break;
-        default:
-            pSERIAL_S(obj)->stopbits = USART_STOPBITS_1;
-    }
-
-    switch (parity) {
-        case ParityNone:
-            pSERIAL_S(obj)->parity = USART_PARITY_NONE;
-            break;
-        case ParityOdd:
-            pSERIAL_S(obj)->parity = USART_PARITY_ODD;
-            break;
-        case ParityEven:
-            pSERIAL_S(obj)->parity = USART_PARITY_EVEN;
-            break;
-        default:
-            pSERIAL_S(obj)->parity = USART_PARITY_NONE;
-    }
-
-    switch (data_bits) {
-        case 5:
-            pSERIAL_S(obj)->character_size = USART_CHARACTER_SIZE_5BIT;
-            break;
-        case 6:
-            pSERIAL_S(obj)->character_size = USART_CHARACTER_SIZE_6BIT;
-            break;
-        case 7:
-            pSERIAL_S(obj)->character_size = USART_CHARACTER_SIZE_7BIT;
-            break;
-        case 8:
-            pSERIAL_S(obj)->character_size = USART_CHARACTER_SIZE_8BIT;
-            break;  //  9 bit transfer not required in mbed
-        default:
-            pSERIAL_S(obj)->character_size = USART_CHARACTER_SIZE_8BIT;
-    }
-
-
-    /* Set stopbits, character size and enable transceivers */
-    ctrlb = (uint32_t)pSERIAL_S(obj)->stopbits | (uint32_t)pSERIAL_S(obj)->character_size;
-
-    /* Check parity mode bits */
-    if (pSERIAL_S(obj)->parity != USART_PARITY_NONE) {
-        ctrla |= SERCOM_USART_CTRLA_FORM(1);
-        ctrlb |= pSERIAL_S(obj)->parity;
-    } else {
-        ctrla |= SERCOM_USART_CTRLA_FORM(0);
-    }
-
-    /* Write configuration to CTRLB */
-    _USART(obj).CTRLB.reg = ctrlb;
-
-    /* Wait until synchronization is complete */
-    usart_syncing(obj);
-
-    /* Write configuration to CTRLA */
-    _USART(obj).CTRLA.reg = ctrla;
-
-    /* Wait until synchronization is complete */
-    usart_syncing(obj);
-
-    enable_usart(obj);
-}
-
-#ifdef DEVICE_SERIAL_FC
-
-void serial_set_flow_control(serial_t *obj, FlowControl type, PinName rxflow, PinName txflow)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    uint32_t muxsetting = 0;
-    uint32_t sercom_index = 0;
-    IRQn_Type irq_n = (IRQn_Type)0;
-    uint32_t vector = 0;
-
-    pSERIAL_S(obj)->pins[USART_RXFLOW_INDEX] = rxflow;
-    pSERIAL_S(obj)->pins[USART_TXFLOW_INDEX] = txflow;
-    muxsetting = serial_find_mux_settings(obj);  // getting mux setting from pins
-    sercom_index = pinmap_merge_sercom(pSERIAL_S(obj)->pins[USART_TX_INDEX], pSERIAL_S(obj)->pins[USART_RX_INDEX]);  // same variable sercom_index reused for optimization
-    if (sercom_index == (uint32_t)NC) {
-        /*expecting a valid value for sercom index*/
-        return;
-    }
-
-    vector = get_serial_vector(obj);
-    irq_n = get_serial_irq_num(obj);
-
-    disable_usart(obj);
-
-    /* Set configuration according to the config struct */
-    pSERIAL_S(obj)->mux_setting = muxsetting;  // mux setting to be changed for configuring hardware control
-    usart_set_config_default(obj);
-
-    struct system_pinmux_config pin_conf;
-    pin_conf.direction = SYSTEM_PINMUX_PIN_DIR_INPUT;
-    pin_conf.input_pull = SYSTEM_PINMUX_PIN_PULL_NONE;
-    pin_conf.powersave    = false;
-
-    for (uint8_t pad = 0; pad < 2; pad++) {  // setting for rx and tx
-        uint32_t current_pin = pSERIAL_S(obj)->pins[pad];
-        if (current_pin != (uint32_t)NC) {
-            pin_conf.mux_position = pinmap_function_sercom(current_pin, sercom_index);
-            if ((uint8_t)NC != pin_conf.mux_position) {
-                system_pinmux_pin_set_config(current_pin, &pin_conf);
-            }
-        }
-    }
-    if((FlowControlRTS == type) || (FlowControlRTSCTS== type))  {
-        if (pSERIAL_S(obj)->pins[USART_RXFLOW_INDEX] != NC) {
-            pin_conf.direction = SYSTEM_PINMUX_PIN_DIR_OUTPUT; // setting for rxflow
-            pin_conf.input_pull = SYSTEM_PINMUX_PIN_PULL_UP;
-            pin_conf.mux_position = pinmap_function_sercom(pSERIAL_S(obj)->pins[USART_RXFLOW_INDEX] , sercom_index);
-            if ((uint8_t)NC != pin_conf.mux_position) {
-                system_pinmux_pin_set_config(pSERIAL_S(obj)->pins[USART_RXFLOW_INDEX], &pin_conf);
-            }
-        }
-    }
-    if((FlowControlCTS == type) || (FlowControlRTSCTS== type)) {
-        if (pSERIAL_S(obj)->pins[USART_TXFLOW_INDEX] != NC) {
-            pin_conf.direction = SYSTEM_PINMUX_PIN_DIR_INPUT; // setting for txflow
-            pin_conf.input_pull = SYSTEM_PINMUX_PIN_PULL_UP;
-            pin_conf.mux_position = pinmap_function_sercom(pSERIAL_S(obj)->pins[USART_TXFLOW_INDEX] , sercom_index);
-            if ((uint8_t)NC != pin_conf.mux_position) {
-                system_pinmux_pin_set_config(pSERIAL_S(obj)->pins[USART_TXFLOW_INDEX], &pin_conf);
-            }
-        }
-    }
-    enable_usart(obj);
-}
-
-#endif  //DEVICE_SERIAL_FC
-
-void serial_break_set(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    struct system_pinmux_config pin_conf;
-    pin_conf.direction = SYSTEM_PINMUX_PIN_DIR_OUTPUT;
-    pin_conf.input_pull = SYSTEM_PINMUX_PIN_PULL_NONE;
-    pin_conf.mux_position = SYSTEM_PINMUX_GPIO;
-    pin_conf.powersave    = false;
-
-    if (pSERIAL_S(obj)->pins[USART_TX_INDEX] != NC) {
-        system_pinmux_pin_set_config(pSERIAL_S(obj)->pins[USART_TX_INDEX], &pin_conf);
-    }
-}
-
-void serial_break_clear(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    uint32_t sercom_index = pinmap_merge_sercom(pSERIAL_S(obj)->pins[USART_TX_INDEX], pSERIAL_S(obj)->pins[USART_RX_INDEX]);
-
-    struct system_pinmux_config pin_conf;
-    pin_conf.direction = SYSTEM_PINMUX_PIN_DIR_INPUT;
-    pin_conf.input_pull = SYSTEM_PINMUX_PIN_PULL_NONE;
-    pin_conf.powersave    = false;
-
-    if (pSERIAL_S(obj)->pins[USART_TX_INDEX] != NC) {
-        pin_conf.mux_position = pinmap_function_sercom(pSERIAL_S(obj)->pins[USART_TX_INDEX], sercom_index);
-        if ((uint8_t)NC != pin_conf.mux_position) {
-            system_pinmux_pin_set_config(pSERIAL_S(obj)->pins[USART_TX_INDEX], &pin_conf);
-        }
-    }
-}
-
-/******************************************************************************
- * INTERRUPTS HANDLING
- ******************************************************************************/
-inline uint8_t serial_get_index(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    switch ((int)pUSART_S(obj)) {
-        case UART_0:
-            return 0;
-        case UART_1:
-            return 1;
-        case UART_2:
-            return 2;
-        case UART_3:
-            return 3;
-        case UART_4:
-            return 4;
-        case UART_5:
-            return 5;
-    }
-    return 0;
-}
-
-static inline void uart_irq(SercomUsart *const usart, uint32_t index)
-{
-    MBED_ASSERT(usart != (void*)0);
-    uint16_t interrupt_status;
-    interrupt_status = usart->INTFLAG.reg;
-    interrupt_status &= usart->INTENSET.reg;
-
-    if (serial_irq_ids[index] != 0) {
-        if (interrupt_status & SERCOM_USART_INTFLAG_TXC) { // for transmit complete
-            usart->INTFLAG.reg = SERCOM_USART_INTFLAG_TXC;
-            irq_handler(serial_irq_ids[index], TxIrq);
-        }
-        if (interrupt_status & SERCOM_USART_INTFLAG_RXC) { // for receive complete
-            usart->INTFLAG.reg = SERCOM_USART_INTFLAG_RXC;
-            irq_handler(serial_irq_ids[index], RxIrq);
-        }
-    }
-}
-
-void uart0_irq()
-{
-    uart_irq((SercomUsart *)UART_0, 0);
-}
-
-void uart1_irq()
-{
-    uart_irq((SercomUsart *)UART_1, 1);
-}
-
-void uart2_irq()
-{
-    uart_irq((SercomUsart *)UART_2, 2);
-}
-
-void uart3_irq()
-{
-    uart_irq((SercomUsart *)UART_3, 3);
-}
-
-void uart4_irq()
-{
-    uart_irq((SercomUsart *)UART_4, 4);
-}
-
-void uart5_irq()
-{
-    uart_irq((SercomUsart *)UART_5, 5);
-}
-
-uint32_t get_serial_vector (serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    uint32_t vector = 0;
-    switch ((int)pUSART_S(obj)) {
-        case UART_0:
-            vector = (uint32_t)uart0_irq;
-            break;
-        case UART_1:
-            vector = (uint32_t)uart1_irq;
-            break;
-        case UART_2:
-            vector = (uint32_t)uart2_irq;
-            break;
-        case UART_3:
-            vector = (uint32_t)uart3_irq;
-            break;
-        case UART_4:
-            vector = (uint32_t)uart4_irq;
-            break;
-        case UART_5:
-            vector = (uint32_t)uart5_irq;
-            break;
-    }
-    return vector;
-}
-
-void serial_irq_handler(serial_t *obj, uart_irq_handler handler, uint32_t id)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    irq_handler = handler;
-    serial_irq_ids[serial_get_index(obj)] = id;
-}
-
-IRQn_Type get_serial_irq_num (serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    switch ((int)pUSART_S(obj)) {
-        case UART_0:
-            return SERCOM0_IRQn;
-        case UART_1:
-            return SERCOM1_IRQn;
-        case UART_2:
-            return SERCOM2_IRQn;
-        case UART_3:
-            return SERCOM3_IRQn;
-        case UART_4:
-            return SERCOM4_IRQn;
-        case UART_5:
-            return SERCOM5_IRQn;
-        default:
-            MBED_ASSERT(0);
-    }
-    return SERCOM0_IRQn; // to avoid warning
-}
-
-void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    IRQn_Type irq_n = (IRQn_Type)0;
-    uint32_t vector = 0;
-
-    vector = get_serial_vector(obj);
-    irq_n = get_serial_irq_num(obj);
-
-    if (enable) {
-        switch (irq) {
-            case RxIrq:
-                _USART(obj).INTENSET.reg = SERCOM_USART_INTFLAG_RXC;
-                break;
-            case TxIrq:
-                _USART(obj).INTENSET.reg = SERCOM_USART_INTFLAG_TXC;
-                break;
-        }
-        NVIC_SetVector(irq_n, vector);
-        NVIC_EnableIRQ(irq_n);
-
-    } else {
-        switch (irq) {
-            case RxIrq:
-                _USART(obj).INTENCLR.reg = SERCOM_USART_INTFLAG_RXC;
-                break;
-            case TxIrq:
-                _USART(obj).INTENCLR.reg = SERCOM_USART_INTFLAG_TXC;
-                break;
-        }
-        NVIC_DisableIRQ(irq_n);
-    }
-}
-
-/******************************************************************************
- * READ/WRITE
- ******************************************************************************/
-int serial_getc(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    while (!serial_readable(obj));
-    return _USART(obj).DATA.reg ;
-}
-
-void serial_putc(serial_t *obj, int c)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    uint16_t q = (c & SERCOM_USART_DATA_MASK);
-    while (!serial_writable(obj));
-    _USART(obj).DATA.reg = q;
-    while (!(_USART(obj).INTFLAG.reg & SERCOM_USART_INTFLAG_TXC));  // wait till data is sent
-}
-
-int serial_readable(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    uint32_t status = 1;
-    if (!(_USART(obj).INTFLAG.reg & SERCOM_USART_INTFLAG_RXC)) {
-        status = 0;
-    } else {
-        status = 1;
-    }
-    return status;
-}
-
-int serial_writable(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    uint32_t status = 1;
-    if (!(_USART(obj).INTFLAG.reg & SERCOM_USART_INTFLAG_DRE)) {
-        status = 0;
-    } else {
-        status = 1;
-    }
-    return status;
-}
-
-/************************************************************************************
- * 			ASYNCHRONOUS HAL														*
- ************************************************************************************/
-
-#if DEVICE_SERIAL_ASYNCH
-
-/************************************
- * HELPER FUNCTIONS					*
- ***********************************/
-void serial_tx_enable_event(serial_t *obj, int event, uint8_t enable)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    if(enable) {
-        pSERIAL_S(obj)->events |= event;
-    } else {
-        pSERIAL_S(obj)->events &= ~ event;
-    }
-}
-
-void serial_rx_enable_event(serial_t *obj, int event, uint8_t enable)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    if(enable) {
-        pSERIAL_S(obj)->events |= event;
-    } else {
-        pSERIAL_S(obj)->events &= ~ event;
-    }
-}
-
-void serial_tx_buffer_set(serial_t *obj, void *tx, int tx_length, uint8_t width)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    MBED_ASSERT(tx != (void*)0);
-    // We only support byte buffers for now
-    MBED_ASSERT(width == 8);
-
-    if(serial_tx_active(obj)) return;
-
-    obj->tx_buff.buffer = tx;
-    obj->tx_buff.length = tx_length;
-    obj->tx_buff.pos = 0;
-
-    return;
-}
-
-void serial_rx_buffer_set(serial_t *obj, void *rx, int rx_length, uint8_t width)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    MBED_ASSERT(rx != (void*)0);
-    // We only support byte buffers for now
-    MBED_ASSERT(width == 8);
-
-    if(serial_rx_active(obj)) return;
-
-    obj->rx_buff.buffer = rx;
-    obj->rx_buff.length = rx_length;
-    obj->rx_buff.pos = 0;
-
-    return;
-}
-
-void serial_set_char_match(serial_t *obj, uint8_t char_match)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    if (char_match != SERIAL_RESERVED_CHAR_MATCH) {
-        obj->char_match = char_match;
-    }
-}
-
-/************************************
- * TRANSFER FUNCTIONS				*
- ***********************************/
-int serial_tx_asynch(serial_t *obj, const void *tx, size_t tx_length, uint8_t tx_width, uint32_t handler, uint32_t event, DMAUsage hint)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    MBED_ASSERT(tx != (void*)0);
-    if(tx_length == 0) return 0;
-
-    serial_tx_buffer_set(obj, (void *)tx, tx_length, tx_width);
-    serial_tx_enable_event(obj, event, true);
-
-//    if( hint == DMA_USAGE_NEVER) {  //TODO: DMA to be implemented later
-    NVIC_ClearPendingIRQ(get_serial_irq_num(obj));
-    NVIC_DisableIRQ(get_serial_irq_num(obj));
-    NVIC_SetVector(get_serial_irq_num(obj), (uint32_t)handler);
-    NVIC_EnableIRQ(get_serial_irq_num(obj));
-
-    if (pUSART_S(obj)) {
-        _USART(obj).INTENCLR.reg = SERCOM_USART_INTFLAG_TXC;
-        _USART(obj).INTENSET.reg = SERCOM_USART_INTFLAG_DRE;
-    }
-//	}
-    return 0;
-}
-
-void serial_rx_asynch(serial_t *obj, void *rx, size_t rx_length, uint8_t rx_width, uint32_t handler, uint32_t event, uint8_t char_match, DMAUsage hint)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    MBED_ASSERT(rx != (void*)0);
-
-    serial_rx_enable_event(obj, SERIAL_EVENT_RX_ALL, false);
-    serial_rx_enable_event(obj, event, true);
-    serial_set_char_match(obj, char_match);
-    serial_rx_buffer_set(obj, rx, rx_length, rx_width);
-
-//    if( hint == DMA_USAGE_NEVER) {  //TODO: DMA to be implemented later
-    NVIC_ClearPendingIRQ(get_serial_irq_num(obj));
-    NVIC_DisableIRQ(get_serial_irq_num(obj));
-    NVIC_SetVector(get_serial_irq_num(obj), (uint32_t)handler);
-    NVIC_EnableIRQ(get_serial_irq_num(obj));
-
-    if (pUSART_S(obj)) {
-        _USART(obj).INTENSET.reg = SERCOM_USART_INTFLAG_RXC;
-    }
-//	}
-    return;
-}
-
-uint8_t serial_tx_active(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    return ((obj->tx_buff.length > 0) ? true : false);
-}
-
-uint8_t serial_rx_active(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    return ((obj->rx_buff.length > 0) ? true : false);
-}
-
-int serial_tx_irq_handler_asynch(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    _USART(obj).INTENCLR.reg = SERCOM_USART_INTFLAG_TXC;
-    serial_tx_abort_asynch(obj);
-    return SERIAL_EVENT_TX_COMPLETE & obj->serial.events;
-}
-
-int serial_rx_irq_handler_asynch(serial_t *obj)
-{
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    int event = 0;
-    /* This interrupt handler is called from USART irq */
-    uint8_t *buf = (uint8_t*)obj->rx_buff.buffer;
-    uint8_t error_code = 0;
-    uint16_t received_data = 0;
-
-    error_code = (uint8_t)(_USART(obj).STATUS.reg & SERCOM_USART_STATUS_MASK);
-    /* Check if an error has occurred during the receiving */
-    if (error_code) {
-        /* Check which error occurred */
-        if (error_code & SERCOM_USART_STATUS_FERR) {
-            /* Store the error code and clear flag by writing 1 to it */
-            _USART(obj).STATUS.reg |= SERCOM_USART_STATUS_FERR;
-            return SERIAL_EVENT_RX_FRAMING_ERROR;
-        } else if (error_code & SERCOM_USART_STATUS_BUFOVF) {
-            /* Store the error code and clear flag by writing 1 to it */
-            _USART(obj).STATUS.reg |= SERCOM_USART_STATUS_BUFOVF;
-            return SERIAL_EVENT_RX_OVERFLOW;
-        } else if (error_code & SERCOM_USART_STATUS_PERR) {
-            /* Store the error code and clear flag by writing 1 to it */
-            _USART(obj).STATUS.reg |= SERCOM_USART_STATUS_PERR;
-            return SERIAL_EVENT_RX_PARITY_ERROR;
-        }
-    }
-
-    /* Read current packet from DATA register,
-    * increment buffer pointer and decrement buffer length */
-    received_data = (_USART(obj).DATA.reg & SERCOM_USART_DATA_MASK);
-
-    /* Read value will be at least 8-bits long */
-    buf[obj->rx_buff.pos] = received_data;
-    /* Increment 8-bit pointer */
-    obj->rx_buff.pos++;
-
-    /* Check if the last character have been received */
-    if(--(obj->rx_buff.length) == 0) {
-        event |= SERIAL_EVENT_RX_COMPLETE;
-        if((buf[obj->rx_buff.pos - 1] == obj->char_match) && (obj->serial.events & SERIAL_EVENT_RX_CHARACTER_MATCH)) {
-            event |= SERIAL_EVENT_RX_CHARACTER_MATCH;
-        }
-        _USART(obj).INTFLAG.reg = SERCOM_USART_INTFLAG_RXC;
-        serial_rx_abort_asynch(obj);
-        return event & obj->serial.events;
-    }
-
-    /* Check for character match event */
-    if((buf[obj->rx_buff.pos - 1] == obj->char_match) && (obj->serial.events & SERIAL_EVENT_RX_CHARACTER_MATCH)) {
-        event |= SERIAL_EVENT_RX_CHARACTER_MATCH;
-    }
-
-    /* Return to the call back if character match occured */
-    if(event != 0) {
-        serial_rx_abort_asynch(obj);
-        return event & obj->serial.events;
-    }
-    return 0;
-}
-
-int serial_irq_handler_asynch(serial_t *obj)
-{
-//TODO: DMA to be implemented
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    uint16_t interrupt_status;
-    uint8_t *buf = obj->tx_buff.buffer;
-
-    interrupt_status = _USART(obj).INTFLAG.reg;
-    interrupt_status &= _USART(obj).INTENSET.reg;
-
-    if (pUSART_S(obj)) {
-        if (interrupt_status & SERCOM_USART_INTFLAG_DRE) {
-            /* Interrupt has another TX source */
-            if(obj->tx_buff.pos >= obj->tx_buff.length) {
-                /* Transfer complete. Switch off interrupt and return event. */
-                _USART(obj).INTENCLR.reg = SERCOM_USART_INTFLAG_DRE;
-                _USART(obj).INTENSET.reg = SERCOM_USART_INTFLAG_TXC;
-            } else {
-                while((serial_writable(obj)) && (obj->tx_buff.pos <= (obj->tx_buff.length - 1))) {
-                    _USART(obj).DATA.reg = buf[obj->tx_buff.pos];
-                    obj->tx_buff.pos++;
-                }
-            }
-        }
-        if (interrupt_status & SERCOM_USART_INTFLAG_TXC) {
-            return serial_tx_irq_handler_asynch(obj);
-        }
-        if (interrupt_status & SERCOM_USART_INTFLAG_RXC) {
-            return serial_rx_irq_handler_asynch(obj);
-        }
-    }
-    return 0;
-}
-
-void serial_tx_abort_asynch(serial_t *obj)
-{
-//TODO: DMA to be implemented
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    _USART(obj).INTFLAG.reg = SERCOM_USART_INTFLAG_TXC;
-    obj->tx_buff.length = 0;
-    obj->rx_buff.pos = 0;
-
-}
-
-void serial_rx_abort_asynch(serial_t *obj)
-{
-//TODO: DMA to be implemented
-    /* Sanity check arguments */
-    MBED_ASSERT(obj);
-    _USART(obj).INTFLAG.reg = SERCOM_USART_INTFLAG_RXC;
-    obj->rx_buff.length = 0;
-    obj->rx_buff.pos = 0;
-}
-
-#endif
\ No newline at end of file