keychron_qmk_firmware/drivers/avr/i2c_slave.c
yiancar 72fd49b146 DC01 keyboard addition (#3428)
* DC01 initial commit

- Addition of directories
- Left readme

* Initial commit of left half

* Initial files for right half

* arrow

* i2c adjustments

* I2C slave and DC01 refractoring

- Cleaned up state machine of I2C slave driver
- Modified DC01 left to use already pressent I2C master driver
- Modified DC01 matrixes

* Fixed tabs to spaces

* Addition of Numpad

* Add keymaps

- Orthopad keymap for numpad module
- Numpad keymap for numpad module
- ISO, ANSI and HHKB version of keymap for right module

* Minor matrix.c fixes

* Update Readmes
2018-07-18 12:55:57 -04:00

68 lines
2.0 KiB
C
Executable File

/* Library made by: g4lvanix
* Github repository: https://github.com/g4lvanix/I2C-slave-lib
*/
#include <avr/io.h>
#include <util/twi.h>
#include <avr/interrupt.h>
#include <stdbool.h>
#include "i2c_slave.h"
void i2c_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){
// 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
slave_has_register_set = false;
break;
case TW_SR_DATA_ACK:
// This device is a slave receiver and has received data
// First byte is the location then the bytes will be writen in buffer with auto-incriment
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;
}
slave_has_register_set = true; // address has been receaved now fill in buffer
} else {
rxbuffer[buffer_address] = TWDR;
buffer_address++;
}
break;
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];
buffer_address++;
break;
case TW_BUS_ERROR:
// We got an error, reset i2c
TWCR = 0;
default:
break;
}
// Reset i2c state mahcine to be ready for next interrupt
TWCR |= (1 << TWIE) | (1 << TWINT) | (ack << TWEA) | (1 << TWEN);
}