Files

102 lines
2.3 KiB
C

#include <stdint.h>
#include <stdbool.h>
#include <avr/io.h>
#include "config.h"
#include "pump.h"
#include "twi.h"
#define BUFFER_SIZE 4
static uint8_t twiBuffer[BUFFER_SIZE] = {0};
static uint8_t bufferIndex = 0;
bool respondFlag = false;
static inline void twiReset(void) {
// Enable TWI; enable ACK; clear interrupt flag; enable twi external interrupt
TWCR = (1 << TWEN) | (1 << TWEA) | (1 << TWINT) | (1 << TWIE);
}
void twiInit(void) {
TWAR = ((eepromRead(TWI_ADDR)) << 1); //address definition found in config.h
twiReset();
}
static inline void twiSendAck(void) {
TWCR = (1 << TWEA) | (1 << TWINT);
}
static inline void twiSendNack(void) {
TWCR = (TWCR & ~(1 << TWEA)) | (1 << TWINT);
}
static void twiSendData(uint8_t data) {
TWDR = data;
twiSendAck();
}
void twiRespond(void) {
if (!respondFlag) return;
uint8_t cmd = twiBuffer[0];
uint8_t param = twiBuffer[1];
switch(cmd) {
// READ
case 0x01:
twiSendData(*pLastMoistureVal);
break;
case 0x02:
twiSendData(eepromRead(SENSOR_READINGS));
break;
case 0x03:
twiSendData(eepromRead(MOISTURE_MIN));
break;
case 0x04:
twiSendData(eepromRead(MOISTURE_MAX));
break;
// WRITE
case 0x05:
eepromWrite(SENSOR_READINGS, param);
twiSendAck();
break;
case 0x06:
eepromWrite(MOISTURE_MIN, param);
twiSendAck();
break;
case 0x07:
eepromWrite(MOISTURE_MAX, param);
twiSendAck();
break;
case 0x08:
waterPlant();
twiSendAck();
break;
default:
twiSendNack();
break;
}
}
void twiListen(void) {
switch (TWSR & 0xF8) {
case 0x60: // SLA+W received
bufferIndex = 0;
twiSendAck();
break;
case 0x80: // data received
if(bufferIndex < BUFFER_SIZE) {
twiBuffer[bufferIndex++] = TWDR;
twiSendAck();
} else twiSendNack();
break;
case 0xA0: // stop condition
respondFlag = true;
twiReset();
break;
default:
twiSendNack();
break;
}
}