TSIHW.cpp

00001 #include "mbed.h"
00002 #include "TSIHW.h"
00003 
00004 /* TSI constructor
00005 Parameters: the values of the fields REFCHRG, EXTCHRG, DVOLT, PS, and NSCN from TSI0_GENCS register
00006 Not using interrupts, capacitive sensing (non-noise detection), not configured to work in STOP modes
00007 */
00008 TSI::TSI(char rchg, char echg, char dvolt, char ps, char nscn) {
00009     // The first version is preconfigured for non-noise detection, no interrupts, not running on stop modes, software trigger
00010     SIM->SCGC5 |= 0x00000E20; // clock gate for TSI and PORTS A, B, and C
00011     TSI0->GENCS = 0xC0000080 | ((rchg & 0x07) << 21) | ((echg & 0x07) << 16) | ((dvolt & 0x03) << 19) | ((ps & 0x07) << 13) | ((nscn & 0x1F) << 8);
00012 }
00013 
00014 /* TSI destructor */
00015 TSI::~TSI() { }
00016 
00017 /* Function to configure a pin to work with the corresponding channel (passed as the single parameter) */
00018 void TSI::ActivateChannel(char ch) {
00019     // reads channel number and sets the MUX of the corresponding pin to ALT0 function
00020     switch(ch) {
00021         case 0: PORTB->PCR[0] &= 0xFFFFF8FF; break;
00022         case 1: PORTA->PCR[0] &= 0xFFFFF8FF; break;
00023         case 2: PORTA->PCR[1] &= 0xFFFFF8FF; break;
00024         case 3: PORTA->PCR[2] &= 0xFFFFF8FF; break;
00025         case 4: PORTA->PCR[3] &= 0xFFFFF8FF; break;
00026         case 5: PORTA->PCR[4] &= 0xFFFFF8FF; break;
00027         case 6: PORTB->PCR[1] &= 0xFFFFF8FF; break;
00028         case 7: PORTB->PCR[2] &= 0xFFFFF8FF; break;
00029         case 8: PORTB->PCR[3] &= 0xFFFFF8FF; break;
00030         case 9: PORTB->PCR[16] &= 0xFFFFF8FF; break;
00031         case 10: PORTB->PCR[17] &= 0xFFFFF8FF; break;
00032         case 11: PORTB->PCR[18] &= 0xFFFFF8FF; break;
00033         case 12: PORTB->PCR[19] &= 0xFFFFF8FF; break;
00034         case 13: PORTC->PCR[0] &= 0xFFFFF8FF; break;
00035         case 14: PORTC->PCR[1] &= 0xFFFFF8FF; break;
00036         case 15: PORTC->PCR[2] &= 0xFFFFF8FF; break;
00037         default: error("PinName provided to TSI::ActivateChannel() does not correspond to any known TSI channel.");
00038     }
00039 }
00040 
00041 // Function to trigger the reading of a given channel
00042 void TSI::Start(char ch) {
00043     //writes 1 to the software trigger bit, defining the channel number in the respective bits
00044     TSI0->GENCS |= 0x00000004; // clears EOSF
00045     TSI0->DATA = 0x00400000 | (ch << 28);
00046 }
00047 
00048 // Function to read scan result; returns zero if not finished
00049 uint16_t TSI::Read() {
00050     uint16_t aux;
00051     
00052     if(!(TSI0->GENCS & 0x00000004)) {
00053         return 0;
00054     } else {
00055         aux = TSI0->DATA & 0x0000FFFF;
00056         TSI0->GENCS |= 0x00000004; // clears EOSF
00057         return aux;
00058     }
00059 }