This is a VERY low-level library for controlling the TSI hardware module in a KL25 microcontroller. The programmer creates the TSI object passing basic parameters, and selects the active channels. Then, a scan on a given channel can be started, and the raw result can be read.
TSIHW.cpp
- Committer:
- quevedo
- Date:
- 2014-09-26
- Revision:
- 1:532aa572220b
- Parent:
- 0:b39f4f954a9b
File content as of revision 1:532aa572220b:
#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 |= 0x00000E20; // clock gate for TSI and PORTS A, B, and C 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; } }