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MCUXpresso: Update the I2C implmentation for byte read and write 

1. Start function: Issue repeat start when bus is busy
2. Byte write function: Do not call SDK function as this does
   not work for some of the Kinetis device
3. Byte read function: Do not call SDK function as this would
   issue a START and STOP signal which is not required for
   I2C byte functions

Signed-off-by: Mahesh Mahadevan <mahesh.mahadevan@nxp.com>
pull/6310/head
Mahesh Mahadevan 2018-03-09 08:32:22 -06:00
parent 53fa4e5fc4
commit 5230bcaf6f
1 changed files with 54 additions and 28 deletions
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80
targets/TARGET_Freescale/TARGET_MCUXpresso_MCUS/api/i2c_api.c
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@ -67,12 +67,14 @@ int i2c_start(i2c_t *obj)
I2C_Type *base = i2c_addrs[obj->instance];
uint32_t statusFlags = I2C_MasterGetStatusFlags(base);
/* Return an error if the bus is already in use. */
/* Check if the bus is already in use. */
if (statusFlags & kI2C_BusBusyFlag) {
return 1;
}
/* Send a repeat START signal. */
base->C1 |= I2C_C1_RSTA_MASK;
} else {
/* Send the START signal. */
base->C1 |= I2C_C1_MST_MASK | I2C_C1_TX_MASK;
}
#if defined(FSL_FEATURE_I2C_HAS_DOUBLE_BUFFERING) && FSL_FEATURE_I2C_HAS_DOUBLE_BUFFERING
while (!(base->S2 & I2C_S2_EMPTY_MASK))
@ -85,7 +87,6 @@ int i2c_start(i2c_t *obj)
int i2c_stop(i2c_t *obj)
{
obj->next_repeated_start = 0;
if (I2C_MasterStop(i2c_addrs[obj->instance]) != kStatus_Success) {
return 1;
}
@ -183,39 +184,64 @@ int i2c_byte_read(i2c_t *obj, int last)
{
uint8_t data;
I2C_Type *base = i2c_addrs[obj->instance];
i2c_master_transfer_t master_xfer;
memset(&master_xfer, 0, sizeof(master_xfer));
master_xfer.slaveAddress = i2c_address;
master_xfer.direction = kI2C_Read;
master_xfer.data = &data;
master_xfer.dataSize = 1;
/* Setup the I2C peripheral to receive data. */
base->C1 &= ~(I2C_C1_TX_MASK | I2C_C1_TXAK_MASK);
/* The below function will issue a STOP signal at the end of the transfer.
* This is required by the hardware in order to receive the last byte
*/
if (I2C_MasterTransferBlocking(base, &master_xfer) != kStatus_Success) {
return I2C_ERROR_NO_SLAVE;
if (last) {
base->C1 |= I2C_C1_TXAK_MASK; // NACK
}
data = (base->D & 0xFF);
/* Change direction to Tx to avoid extra clocks. */
base->C1 |= I2C_C1_TX_MASK;
/* Wait until data transfer complete. */
while (!(base->S & kI2C_IntPendingFlag))
{
}
/* Clear the IICIF flag. */
base->S = kI2C_IntPendingFlag;
return data;
}
int i2c_byte_write(i2c_t *obj, int data)
{
status_t ret_value;
#if FSL_I2C_DRIVER_VERSION > MAKE_VERSION(2, 0, 1)
ret_value = I2C_MasterWriteBlocking(i2c_addrs[obj->instance], (uint8_t *)(&data), 1, kI2C_TransferNoStopFlag);
#else
ret_value = I2C_MasterWriteBlocking(i2c_addrs[obj->instance], (uint8_t *)(&data), 1);
#endif
int ret_value = 1;
uint8_t statusFlags = 0;
I2C_Type *base = i2c_addrs[obj->instance];
if (ret_value == kStatus_Success) {
return 1;
} else if (ret_value == kStatus_I2C_Nak) {
return 0;
} else {
return 2;
/* Setup the I2C peripheral to transmit data. */
base->C1 |= I2C_C1_TX_MASK;
/* Send a byte of data. */
base->D = data;
/* Wait until data transfer complete. */
while (!(base->S & kI2C_IntPendingFlag)) {
}
statusFlags = base->S;
/* Clear the IICIF flag. */
base->S = kI2C_IntPendingFlag;
/* Check if arbitration lost */
if (statusFlags & kI2C_ArbitrationLostFlag) {
base->S = kI2C_ArbitrationLostFlag;
ret_value = 2;
}
/* Check if no acknowledgement (NAK) */
if (statusFlags & kI2C_ReceiveNakFlag) {
base->S = kI2C_ReceiveNakFlag;
ret_value = 0;
}
return ret_value;
}