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Rename i2c_slave functions so it can coexist with i2c_master (#4875)

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Also merges tx/rx buffers, as only one is necessary.
This commit is contained in:
James Churchill 2019-01-23 02:57:13 +10:00 • committed by Drashna Jaelre
parent 127ec5f1e3
commit 8cf7265f8f
5 changed files with 36 additions and 38 deletions
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25
drivers/avr/i2c_slave.c
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@ -9,23 +9,26 @@
#include "i2c_slave.h"
void i2c_init(uint8_t address){
volatile uint8_t i2c_slave_reg[I2C_SLAVE_REG_COUNT];
static volatile uint8_t buffer_address;
static volatile bool slave_has_register_set = false;
void i2c_slave_init(uint8_t address){
// load address into TWI address register
TWAR = (address << 1);
// set the TWCR to enable address matching and enable TWI, clear TWINT, enable TWI interrupt
TWCR = (1 << TWIE) | (1 << TWEA) | (1 << TWINT) | (1 << TWEN);
}
void i2c_stop(void){
void i2c_slave_stop(void){
// clear acknowledge and enable bits
TWCR &= ~((1 << TWEA) | (1 << TWEN));
}
ISR(TWI_vect){
uint8_t ack = 1;
// temporary stores the received data
//uint8_t data;
switch(TW_STATUS){
case TW_SR_SLA_ACK:
// The device is now a slave receiver
@ -38,13 +41,13 @@ ISR(TWI_vect){
if(!slave_has_register_set){
buffer_address = TWDR;
if (buffer_address >= RX_BUFFER_SIZE){ // address out of bounds dont ack
ack = 0;
buffer_address = 0;
if (buffer_address >= I2C_SLAVE_REG_COUNT) { // address out of bounds dont ack
ack = 0;
buffer_address = 0;
}
slave_has_register_set = true; // address has been receaved now fill in buffer
} else {
rxbuffer[buffer_address] = TWDR;
i2c_slave_reg[buffer_address] = TWDR;
buffer_address++;
}
break;
@ -52,7 +55,7 @@ ISR(TWI_vect){
case TW_ST_SLA_ACK:
case TW_ST_DATA_ACK:
// This device is a slave transmitter and master has requested data
TWDR = txbuffer[buffer_address];
TWDR = i2c_slave_reg[buffer_address];
buffer_address++;
break;
@ -63,6 +66,6 @@ ISR(TWI_vect){
break;
}
// Reset i2c state mahcine to be ready for next interrupt
// Reset i2c state machine to be ready for next interrupt
TWCR |= (1 << TWIE) | (1 << TWINT) | (ack << TWEA) | (1 << TWEN);
}