65 lines
1.1 KiB
C
65 lines
1.1 KiB
C
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#include "lib/mystd.h"
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#include <avr/io.h>
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#include <util/twi.h>
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#include "lib/i2c.h"
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static inline t_error i2c_wait(void) {
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uint16_t o = 0;
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// wait until done
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while (!(TWCR & BV(TWINT)) && o < 32768)
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o++;
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if (o >= 32768)
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return ERROR;
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return NO_ERROR;
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}
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void i2c_init(void) {
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// clear the status registers
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TWSR = 0x00;
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// set the i2c clock speed
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TWBR = ((F_CPU / I2C_CLOCK) - 16) / 2;
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}
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t_error i2c_start(void) {
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// CLR INT | SET MASTER | ENABLE ;
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TWCR = BV(TWINT) | BV(TWSTA) | BV(TWEN);
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ERR_RET(i2c_wait());
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return NO_ERROR;
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}
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t_error i2c_stop(void) {
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// CLR INT | ENABLE | STOP ;
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TWCR = BV(TWINT) | BV(TWEN) | BV(TWSTO);
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return NO_ERROR;
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}
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t_error i2c_write(uint8_t data) {
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// set data to write
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TWDR = data;
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// CLR INT | ENABLE ;
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TWCR = BV(TWINT) | BV(TWEN);
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ERR_RET(i2c_wait());
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return NO_ERROR;
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}
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t_error i2c_read_ack(uint8_t* out) {
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TWCR = BV(TWINT) | BV(TWEN) | BV(TWEA);
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ERR_RET(i2c_wait());
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*out = TWDR;
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return NO_ERROR;
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}
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t_error i2c_read_nack(uint8_t* out) {
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TWCR = BV(TWINT) | BV(TWEN);
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ERR_RET(i2c_wait());
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*out = TWDR;
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return NO_ERROR;
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}
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