static void i2cs_send(char c)
{
I2C_WAIT();
while( TW_STATUS != TW_ST_SLA_ACK && TW_STATUS != TW_ST_DATA_ACK ) {
I2C_ACK();
}
I2C_SEND(c);
}
static char i2cs_recv(void)
{
I2C_WAIT();
while( TW_STATUS != TW_SR_DATA_ACK ) {
I2C_ACK();
}
char c = TWDR;
I2C_ACK();
return c;
}
int i2c_write(uint32_t bus, uint8_t address, const uint8_t len, uint8_t *buf,
uint8_t nostop) {
I2C_ *ib = (I2C_ *)bus;
int timeout;
int i, j;
volatile uint32_t tmp;
timeout = 0x10000;
/* LSB must be zero, since it differentiates between read and write */
if (address & 0x01) {
return -1;
}
if (i2c_start(bus)) {
return -2;
}
/* Send address, low bit 0 for read */
ib->DR = (uint8_t)address;
/* Wait until address is set */
I2C_WAIT(!(ib->SR1 & I2C_SR1_ADDR), timeout, -3);
#if 0
for (i=0; i < timeout && !(ib->SR1 & I2C_SR1_ADDR); i++) {
i2c_busywait(100);
}
if (i >= timeout) {
return -81;
}
#endif
/* Clear ADDR in SR1 by reading SR1 and SR2 */
tmp = ib->SR1;
tmp = ib->SR2;
for (j=0;
j<len;
j++) {
/* Send byte */
ib->DR = buf[j];
/* Wait until byte is sent is set */
for (i=0;
i < timeout && !(ib->SR1 & I2C_SR1_TXE);
i++) {
i2c_busywait(100);
}
if (i >= timeout) {
/* Maybe we should do something better here? */
return -82;
}
}
/* Wait until BTF == 1 is set */
for (i=0;
i < timeout && !(ib->SR1 & I2C_SR1_BTF);
i++) {
i2c_busywait(100);
}
if (i >= timeout) {
/* Maybe we should do something better here? */
return -83;
}
if (!nostop) {
ib->CR1 |= (I2C_CR1_STOP);
/* Wait until STOP is cleared by hw */
for (i=0;
i < timeout && (ib->CR1 & I2C_CR1_STOP);
i++) {
i2c_busywait(100);
}
if (i >= timeout) {
return -84;
}
}
return 0;
}
static void I2CM_START(void) { TWCR=_BV(TWEN)|_BV(TWINT)|_BV(TWSTA); I2C_WAIT(); }
static void I2C_NACK(void) { TWCR=_BV(TWEN)|_BV(TWINT); I2C_WAIT(); }