int TwMasterTransact(unsigned char sla, void *txdata, unsigned short txlen, void *rxdata, unsigned short rxsiz, unsigned long tmo)
{
int rc = 0;
unsigned char *cp;
if (txlen) {
TwStart();
/* Send SLA+W and check for ACK. */
if ((rc = TwPut(sla << 1)) == 0) {
for (cp = (unsigned char *) txdata; txlen--; cp++) {
if ((rc = TwPut(*cp)) != 0) {
break;
}
}
}
}
if (rc == 0 && rxsiz) {
TwStart();
/* Send SLA+R and check for ACK. */
if ((rc = TwPut((sla << 1) | 1)) == 0) {
for (cp = rxdata;; cp++) {
*cp = TwGet();
if (++rc >= rxsiz) {
break;
}
TwAck();
}
}
}
TwStop();
return rc;
}
/*!
* \brief Transmit and/or receive data as a master.
*
* The two-wire serial interface must have been initialized by calling
* TwInit() before this function can be used.
*
* \param sla Slave address of the destination. This slave address
* must be specified as a 7-bit address. For example, the
* PCF8574A may be configured to slave addresses from 0x38
* to 0x3F.
* \param txdata Points to the data to transmit. Ignored, if the number
* of data bytes to transmit is zero.
* \param txlen Number of data bytes to transmit. If zero, then the
* interface will not send any data to the slave device
* and will directly enter the master receive mode.
* \param rxdata Points to a buffer, where the received data will be
* stored. Ignored, if the maximum number of bytes to
* receive is zero.
* \param rxsiz Maximum number of bytes to receive. Set to zero, if
* no bytes are expected from the slave device.
* \param tmo Timeout in milliseconds. To disable timeout, set this
* parameter to NUT_WAIT_INFINITE.
*
* \return The number of bytes received, -1 in case of an error or timeout.
*
* \note Timeout is not used in the bit banging version.
*/
int NutTwiMasterTranceive(NUTTWIBUS *bus, uint8_t sla, const void *txdata, uint16_t txlen, void *rxdata, uint16_t rxsiz, uint32_t tmo)
{
int rc = 0;
uint8_t *cp;
NUTTWIICB *icb = bus->bus_icb;
if (!twibb_initialized) {
TwInit(0);
}
/* This routine is marked reentrant, so lock the interface. */
if (NutEventWait(&bus->bus_mutex, tmo)) {
icb->tw_mm_error = TWERR_IF_LOCKED;
return -1;
}
TwStart();
/* Send SLA+W and check for ACK. */
if ((rc = TwPut(sla << 1)) == 0) {
for (cp = (uint8_t *)txdata; txlen--; cp++) {
if ((rc = TwPut(*cp)) != 0) {
break;
}
}
}
if (rc == 0 && rxsiz) {
TwStart();
/* Send SLA+R and check for ACK. */
if ((rc = TwPut((sla << 1) | 1)) == 0) {
for (cp = rxdata;; cp++) {
*cp = TwGet();
if (++rc >= rxsiz) {
break;
}
TwAck();
}
}
}
TwStop();
if (rc == -1) {
icb->tw_mm_error = TWERR_SLA_NACK;
}
/* Release the interface. */
NutEventPost(&bus->bus_mutex);
return rc;
}
