Revision 0:b39f4f954a9b, committed 2014-09-24

Comitter:

quevedo

Date:

Wed Sep 24 18:48:10 2014 +0000

Child:

1:532aa572220b

Commit message:

First version of the low-level library; interrupts not active, does not run in STOP modes

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Registers.txt	Wed Sep 24 18:48:10 2014 +0000
@@ -0,0 +1,51 @@
+/*
+TSI REGISTERS
+------------------------------------------
+
+TSI0_GENCS:
+Bit 31: OUTRGF; Out-of-range flag; set if result register is out of the range given by TSI_THRESHOLD; write 1 to clear
+Bit 28: ESOR; Selector for End-of-scan (set) or out-of-range (clear) interrupt source
+Bits 27-24: MODE; defines analog mode; keep bits 25-24 to 00
+    0000: capacitive sensing (non-noise detection)
+    0100: Single threshold noise detection mode; frequency limitation disabled
+    1000: Single threshold noise detection mode; frequency limitation enabled
+    1100: Automatic noise detection mode
+Bits 23-21: REFCHRG; current value for charging the reference oscillator
+    000: 500nA
+    001: 1uA
+    010: 2uA
+    011: 4uA
+    100: 8uA
+    101: 16uA
+    110: 32uA
+    111: 64uA
+Bits 20-19: DVOLT; oscillator's voltage rails
+    00: DV = 1.03V; Vp = 1.33V; Vm = 0.30V
+    01: DV = 0.73V; Vp = 1.18V; Vm = 0.45V
+    10: DV = 0.43V; Vp = 1.03V; Vm = 0.60V
+    11: DV = 0.29V; Vp = 0.95V; Vm = 0.67V
+Bits 18-16: EXTCHRG; current value for charging the electrode oscillator
+    Same values as for REFCHRG
+Bits 15-13: PS; electrode oscillator prescaler
+    Value is 2 to the power of the number given by the three bits (0-7)
+Bits 12-8: NSCN; Number of scans for each electrode
+    Value is the number given by the five bits (0-31) plus 1.
+Bit 7: TSIEN; TSI enable; set to enable
+Bit 6: TSIIEN; TSI interrupt enable; set to enable
+Bit 5: STPE; STOP enable; set to allow TSI to run in low-power modes
+Bit 4: STM; Scan Trigger Mode; clear to software and set to hardware
+Bit 3: SCNIP; Scan In Progress status; set if there is a scan in progress
+Bit 2: EOSF; End of Scan Flag; set if scan complete
+Bit 1: CURSW; Current sources swapped; set if swapped
+
+TSI0_DATA:
+Bits 31-28: TSICH; current channel to be measured (4 bits, values 0 to 15)
+Bit 23: DMAEN; DMA enabled; set for DMA transfer instead of interrupt
+Bit 22: SWTS; Software Trigger Start; write 1 to start scan if software trigger was selected
+Bit 15-0: TSICNT; TSI Conversion Counter; record the accumulated scan counter value ticked by the reference oscillator
+
+TSI0_TSHD:
+Threshold value
+----------------------------------------------------
+
+*/
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TSIHW.cpp	Wed Sep 24 18:48:10 2014 +0000
@@ -0,0 +1,59 @@
+#include "mbed.h"
+#include "TSIHW.h"
+
+/* TSI constructor
+Parameters: the values of the fields REFCHRG, EXTCHRG, DVOLT, PS, and NSCN from TSI0_GENCS register
+Not using interrupts, capacitive sensing (non-noise detection), not configured to work in STOP modes
+*/
+TSI::TSI(char rchg, char echg, char dvolt, char ps, char nscn) {
+    // The first version is preconfigured for non-noise detection, no interrupts, not running on stop modes, software trigger
+    SIM->SCGC5 |= 0x00000020; // clock gate for TSI
+    TSI0->GENCS = 0xC0000080 | ((rchg & 0x07) << 21) | ((echg & 0x07) << 16) | ((dvolt & 0x03) << 19) | ((ps & 0x07) << 13) | ((nscn & 0x1F) << 8);
+}
+
+/* TSI destructor */
+TSI::~TSI() { }
+
+/* Function to configure a pin to work with the corresponding channel (passed as the single parameter) */
+void TSI::ActivateChannel(char ch) {
+    // reads channel number and sets the MUX of the corresponding pin to ALT0 function
+    switch(ch) {
+        case 0: PORTB->PCR[0] &= 0xFFFFF8FF; break;
+        case 1: PORTA->PCR[0] &= 0xFFFFF8FF; break;
+        case 2: PORTA->PCR[1] &= 0xFFFFF8FF; break;
+        case 3: PORTA->PCR[2] &= 0xFFFFF8FF; break;
+        case 4: PORTA->PCR[3] &= 0xFFFFF8FF; break;
+        case 5: PORTA->PCR[4] &= 0xFFFFF8FF; break;
+        case 6: PORTB->PCR[1] &= 0xFFFFF8FF; break;
+        case 7: PORTB->PCR[2] &= 0xFFFFF8FF; break;
+        case 8: PORTB->PCR[3] &= 0xFFFFF8FF; break;
+        case 9: PORTB->PCR[16] &= 0xFFFFF8FF; break;
+        case 10: PORTB->PCR[17] &= 0xFFFFF8FF; break;
+        case 11: PORTB->PCR[18] &= 0xFFFFF8FF; break;
+        case 12: PORTB->PCR[19] &= 0xFFFFF8FF; break;
+        case 13: PORTC->PCR[0] &= 0xFFFFF8FF; break;
+        case 14: PORTC->PCR[1] &= 0xFFFFF8FF; break;
+        case 15: PORTC->PCR[2] &= 0xFFFFF8FF; break;
+        default: error("PinName provided to TSI::ActivateChannel() does not correspond to any known TSI channel.");
+    }
+}
+
+// Function to trigger the reading of a given channel
+void TSI::Start(char ch) {
+    //writes 1 to the software trigger bit, defining the channel number in the respective bits
+    TSI0->GENCS |= 0x00000004; // clears EOSF
+    TSI0->DATA = 0x00400000 | (ch << 28);
+}
+
+// Function to read scan result; returns zero if not finished
+uint16_t TSI::Read() {
+    uint16_t aux;
+    
+    if(!(TSI0->GENCS & 0x00000004)) {
+        return 0;
+    } else {
+        aux = TSI0->DATA & 0x0000FFFF;
+        TSI0->GENCS |= 0x00000004; // clears EOSF
+        return aux;
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TSIHW.h	Wed Sep 24 18:48:10 2014 +0000
@@ -0,0 +1,50 @@
+#ifndef TSIHW_H
+#define TSIHW_H
+
+#include "mbed.h"
+/**
+* KL25 TSI low-level library with very basic functions
+*
+* @code
+* #include "mbed.h"
+* #include "TSIHW.h"
+* 
+* TSI touch(0,0,0,2,2);
+* Serial pc(USBTX, USBRX);
+* 
+* int main() {
+*     uint16_t s;
+*     
+*     pc.printf("BEGIN\r\n");
+*     touch.ActivateChannel(5); // Electrode connected to PTA4
+*     pc.printf("ACTIVATE\r\n");
+*     while(1) {
+*         s = 0;
+*         touch.Start(5);
+*         pc.printf("START\r\n");
+*         while(!s) {
+*             s = touch.Read();
+*         }
+*         pc.printf("TOUCH: %d\r\n", s);
+*         wait(1);
+*     }
+* }
+* @endcode
+*/
+
+
+class TSI
+{
+public:
+  TSI(char rchg, char echg, char dvolt, char ps, char nscn);
+
+  ~TSI();
+
+  void ActivateChannel(char ch);
+  
+  void Start(char ch);
+  
+  uint16_t Read(void);
+  
+};
+#endif