59 lines
1.3 KiB
C
59 lines
1.3 KiB
C
#include <stdint.h>
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#include <avr/io.h>
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#include "config.h"
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#define BUFFER_SIZE 8
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static inline void twiReset(void) {
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// Enable TWI; enable ACK; clear interrupt flag; enable twi external interrupt
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TWCR = (1 << TWEN) | (1 << TWEA) | (1 << TWINT) | (1 << TWIE);
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}
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void twiInit(void) {
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TWAR = TWI_ADDR; //address definition found in config.h
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twiReset();
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}
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static inline void twiSendAck(void) {
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TWCR = (1 << TWEA) | (1 << TWINT);
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}
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static inline void twiSendNack(void) {
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TWCR = (TWCR & ~(1 << TWEA)) | (1 << TWINT);
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}
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static void twiRespond(int8_t response[]) {
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// Respond to TWI requests
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}
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static void twiExecute(int8_t buffer[]) {
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// Perform actions based on received message
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// if needed:
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// twiRespond();
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}
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void twiAlert(void) {
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static int8_t twiBuffer[BUFFER_SIZE] = {0};
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static uint8_t bufferIndex = 0;
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switch (TWSR & 0xF8) {
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case 0x60: // SLA+W received
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twiSendAck();
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break;
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case 0x80: // data received
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if(bufferIndex < BUFFER_SIZE) {
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twiBuffer[bufferIndex++] = TWDR;
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twiSendAck();
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} else twiSendNack();
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break;
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case 0xA0: // stop condition
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twiExecute(twiBuffer);
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twiReset();
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break;
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default:
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twiSendNack();
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break;
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}
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}
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