static inline int i2c_do_read(i2c_t *obj, int last) {
if (last == 2) {
/* this time is befor last byte read */
/* Set MR3 WAIT bit is 1 */;
REG(MR3.UINT32) |= MR3_WAIT;
} else if (last == 1) {
i2c_set_MR3_NACK(obj);
} else {
i2c_set_MR3_ACK(obj);
}
/* return the data */
return (REG(DRR.UINT32) & 0xFF);
}
int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) {
int count = 0;
int status;
int value;
volatile uint32_t work_reg = 0;
if(length <= 0) {
return 0;
}
i2c_set_MR3_ACK(obj);
/* There is a STOP condition for last processing */
if (obj->last_stop_flag != 0) {
status = i2c_start(obj);
if (status != 0) {
i2c_set_err_noslave(obj);
return I2C_ERROR_BUS_BUSY;
}
}
obj->last_stop_flag = stop;
/* Send Slave address */
status = i2c_read_address_write(obj, (address | 0x01));
if (status != 0) {
i2c_set_err_noslave(obj);
return I2C_ERROR_NO_SLAVE;
}
/* wait RDRF */
status = i2c_wait_RDRF(obj);
/* check ACK/NACK */
if ((status != 0) || ((REG(SR2.UINT32) & SR2_NACKF) != 0)) {
/* Slave sends NACK */
(void)i2c_set_STOP(obj);
/* dummy read */
value = REG(DRR.UINT32);
(void)i2c_wait_STOP(obj);
i2c_set_SR2_NACKF_STOP(obj);
obj->last_stop_flag = 1;
return I2C_ERROR_NO_SLAVE;
}
/* Read in all except last byte */
if (length > 2) {
/* dummy read */
value = REG(DRR.UINT32);
for (count = 0; count < (length - 1); count++) {
/* wait for it to arrive */
status = i2c_wait_RDRF(obj);
if (status != 0) {
i2c_set_err_noslave(obj);
return I2C_ERROR_NO_SLAVE;
}
/* Recieve the data */
if (count == (length - 2)) {
value = i2c_do_read(obj, 1);
} else if ((length >= 3) && (count == (length - 3))) {
value = i2c_do_read(obj, 2);
} else {
value = i2c_do_read(obj, 0);
}
data[count] = (char)value;
}
} else if (length == 2) {
/* Set MR3 WATI bit is 1 */
REG(MR3.UINT32) |= MR3_WAIT;
/* dummy read */
value = REG(DRR.UINT32);
/* wait for it to arrive */
status = i2c_wait_RDRF(obj);
if (status != 0) {
i2c_set_err_noslave(obj);
return I2C_ERROR_NO_SLAVE;
}
i2c_set_MR3_NACK(obj);
data[count] = (char)REG(DRR.UINT32);
count++;
} else {
/* length == 1 */
/* Set MR3 WATI bit is 1 */;
REG(MR3.UINT32) |= MR3_WAIT;
i2c_set_MR3_NACK(obj);
/* dummy read */
value = REG(DRR.UINT32);
}
/* wait for it to arrive */
status = i2c_wait_RDRF(obj);
if (status != 0) {
i2c_set_err_noslave(obj);
return I2C_ERROR_NO_SLAVE;
}
/* If not repeated start, send stop. */
if (stop) {
(void)i2c_set_STOP(obj);
/* RIICnDRR read */
value = (REG(DRR.UINT32) & 0xFF);
data[count] = (char)value;
/* RIICnMR3.WAIT = 0 */
REG(MR3.UINT32) &= ~MR3_WAIT;
(void)i2c_wait_STOP(obj);
i2c_set_SR2_NACKF_STOP(obj);
} else {
(void)i2c_restart(obj);
/* RIICnDRR read */
value = (REG(DRR.UINT32) & 0xFF);
data[count] = (char)value;
/* RIICnMR3.WAIT = 0 */
REG(MR3.UINT32) &= ~MR3_WAIT;
(void)i2c_wait_START(obj);
/* SR2.START = 0 */
REG(SR2.UINT32) &= ~SR2_START;
}
return length;
}
static void i2c_rx_irq(IRQn_Type irq_num, uint32_t index)
{
i2c_t *obj = i2c_data[index].async_obj;
if (obj->rx_buff.pos == SIZE_MAX) {
if ((REG(SR2.UINT32) & SR2_NACKF) != 0) {
/* Slave sends NACK */
(void)i2c_set_STOP(obj);
/* dummy read */
if (REG(DRR.UINT32)) {}
(void)i2c_wait_STOP(obj);
i2c_set_SR2_NACKF_STOP(obj);
obj->i2c.last_stop_flag = 1;
i2c_data[index].event = I2C_EVENT_ERROR | I2C_EVENT_TRANSFER_EARLY_NACK;
i2c_abort_asynch(obj);
((void (*)())i2c_data[index].async_callback)();
return;
}
if (obj->rx_buff.length == 1) {
/* length == 1 */
/* Set MR3 WAIT bit is 1 */;
REG(MR3.UINT32) |= MR3_WAIT;
i2c_set_MR3_NACK(obj);
} else if (obj->rx_buff.length == 2) {
/* Set MR3 WAIT bit is 1 */
REG(MR3.UINT32) |= MR3_WAIT;
}
/* dummy read */
if (REG(DRR.UINT32)) {}
obj->rx_buff.pos = 0;
return;
}
if ((REG(SR2.UINT32) & SR2_NACKF) != 0) {
/* Slave sends NACK */
i2c_set_err_noslave(obj);
i2c_data[index].event = I2C_EVENT_ERROR | I2C_EVENT_TRANSFER_EARLY_NACK;
i2c_abort_asynch(obj);
((void (*)())i2c_data[index].async_callback)();
return;
} else {
switch (obj->rx_buff.length - obj->rx_buff.pos) {
case 1:
/* Finished */
/* If not repeated start, send stop. */
if (i2c_data[index].shouldStop) {
(void)i2c_set_STOP(obj);
/* RIICnDRR read */
*(uint8_t *)obj->rx_buff.buffer = REG(DRR.UINT32) & 0xFF;
/* RIICnMR3.WAIT = 0 */
REG(MR3.UINT32) &= ~MR3_WAIT;
(void)i2c_wait_STOP(obj);
i2c_set_SR2_NACKF_STOP(obj);
} else {
(void)i2c_restart(obj);
/* RIICnDRR read */
*(uint8_t *)obj->rx_buff.buffer = REG(DRR.UINT32) & 0xFF;
/* RIICnMR3.WAIT = 0 */
REG(MR3.UINT32) &= ~MR3_WAIT;
(void)i2c_wait_START(obj);
/* SR2.START = 0 */
REG(SR2.UINT32) &= ~SR2_START;
}
i2c_transfer_finished(obj);
return;
case 2:
i2c_set_MR3_NACK(obj);
break;
case 3:
/* this time is befor last byte read */
/* Set MR3 WAIT bit is 1 */
REG(MR3.UINT32) |= MR3_WAIT;
break;
default:
i2c_set_MR3_ACK(obj);
break;
}
*(uint8_t *)obj->rx_buff.buffer = REG(DRR.UINT32) & 0xFF;
obj->rx_buff.buffer = (uint8_t *)obj->rx_buff.buffer + 1;
++obj->rx_buff.pos;
}
}