99 lines
2.3 KiB
C
99 lines
2.3 KiB
C
|
#include "mma8653.h"
|
||
|
|
#include <util/twi.h>
|
||
|
|
|
||
|
|
#define AXL_ADDR 0x1D
|
||
|
|
#define AXL_ERR_RET(e) if(1){err = e; goto err;}
|
||
|
|
|
||
|
|
#define TRY(c) if(1){ret = c; if (ret) return c;}
|
||
|
|
static int mma8653_i2c_transfer(int write, uint8_t reg, uint8_t *data, uint8_t length)
|
||
|
|
{
|
||
|
|
int err = 0;
|
||
|
|
|
||
|
|
// WRITE TARGET REGISTER
|
||
|
|
// Send start
|
||
|
|
TWCR = (1<<TWINT) | (1<<TWSTA) | (1 << TWEN);
|
||
|
|
while (!(TWCR & (1<<TWINT)));
|
||
|
|
if ((TWSR & 0xF8) != TW_START)
|
||
|
|
AXL_ERR_RET(1);
|
||
|
|
// Send device address
|
||
|
|
TWDR = (AXL_ADDR << 1);
|
||
|
|
TWCR = (1<<TWINT) | (1<<TWEN);
|
||
|
|
while (!(TWCR & (1<<TWINT)));
|
||
|
|
if ((TWSR & 0xF8) != TW_MT_SLA_ACK)
|
||
|
|
AXL_ERR_RET(2);
|
||
|
|
// Write register address
|
||
|
|
TWDR = reg;
|
||
|
|
TWCR = (1<<TWINT) | (1<<TWEN);
|
||
|
|
while (!(TWCR & (1<<TWINT)));
|
||
|
|
if ((TWSR & 0xF8) != TW_MT_DATA_ACK)
|
||
|
|
AXL_ERR_RET(3);
|
||
|
|
|
||
|
|
if (!write) {
|
||
|
|
// Get data
|
||
|
|
// Send re-start
|
||
|
|
TWCR = (1<<TWINT) | (1<<TWSTA) | (1 << TWEN);
|
||
|
|
while (!(TWCR & (1<<TWINT)));
|
||
|
|
if ((TWSR & 0xF8) != TW_REP_START)
|
||
|
|
AXL_ERR_RET(4);
|
||
|
|
// Command a read cycle
|
||
|
|
TWDR = (AXL_ADDR << 1) | (!write);
|
||
|
|
TWCR = (1<<TWINT) | (1<<TWEN);
|
||
|
|
while (!(TWCR & (1<<TWINT)));
|
||
|
|
if ((TWSR & 0xF8) != (write ? TW_MT_SLA_ACK : TW_MR_SLA_ACK))
|
||
|
|
AXL_ERR_RET(5);
|
||
|
|
}
|
||
|
|
while (length--) {
|
||
|
|
if (write) {
|
||
|
|
TWDR = *(data++);
|
||
|
|
TWCR = (1<<TWINT) | (1<<TWEN);
|
||
|
|
while (!(TWCR & (1<<TWINT)));
|
||
|
|
if ((TWSR & 0xF8) != TW_MT_DATA_ACK)
|
||
|
|
AXL_ERR_RET(6);
|
||
|
|
} else {
|
||
|
|
// Read byte
|
||
|
|
TWCR = (1<<TWINT) | (1<<TWEN) | ( (length != 0) << TWEA);
|
||
|
|
while (!(TWCR & (1<<TWINT)));
|
||
|
|
if ((TWSR & 0xF8) != (length != 0 ? TW_MR_DATA_ACK : TW_MR_DATA_NACK))
|
||
|
|
AXL_ERR_RET(6);
|
||
|
|
*(data++) = TWDR;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
// Send stop
|
||
|
|
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
|
||
|
|
while (TWCR & (1<<TWSTO));
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
err:
|
||
|
|
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO); // Send stop to abort
|
||
|
|
return err;
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline int mma8653_i2c_write(uint8_t reg, uint8_t value)
|
||
|
|
{
|
||
|
|
return mma8653_i2c_transfer(1, reg, &value, 1);
|
||
|
|
}
|
||
|
|
|
||
|
|
int mma8653_init() {
|
||
|
|
int ret;
|
||
|
|
|
||
|
|
TWBR = 0xff;
|
||
|
|
//TWSR = 3;
|
||
|
|
|
||
|
|
TRY(mma8653_i2c_write(0x2A, (1 << 1) | (1 << 0)));
|
||
|
|
TRY(mma8653_i2c_write(0x2B, (1 << 7))); // Test mode en
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
int mma8653_get_measurements(struct axl_result *measurements) {
|
||
|
|
int ret;
|
||
|
|
int8_t buffer[4];
|
||
|
|
|
||
|
|
TRY(mma8653_i2c_transfer(0, 0x0, (uint8_t*) buffer, 4));
|
||
|
|
measurements->x = buffer[1];
|
||
|
|
measurements->y = buffer[2];
|
||
|
|
measurements->z = buffer[3];
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|