eSCI Interface in MPC5777c

[vrushalitaklika]

HI,

I am using eSCi interface of MPC5777C to connect to external device.

I am using GPIO 103, 104 pins as TX and RX respectively.

I have configured GPIO[103] as GPIO and OBE and GPIO[104] as GPIO and IBE

These are my transmit and recieve functions

void TransmitData(void)
{
uint8_t j;
for (j=0; j< sizeof (TransData); j++) { /* Loop for character string */
while (eSCI_A.IFSR1.B.TDRE == 0) {} /* Wait for transmit data reg empty = 1 */
eSCI_A.IFSR1.R = 0x8000; /* Clear TDRE flag */

Here instead of writing data to data register of esci, I am writing data to SIU GPDO output register

//eSCI_A.SDR.B.RDTD = TransData[j] << 24; /* Write byte*/

SIU_GPDO[103] = TransData[j] << 24; /* Write byte*/
}

}
void ReceiveData(void)
{
while (eSCI_A.IFSR1.B.RDRF == 0) {} /* Wait for receive data reg full = 1 */
eSCI_A.IFSR1.R = 0x2000; /* Clear RDRF flag */

Same here. Instead of reading data from data register of esci, I am reading data directly from SIU GPDI input register
//RecData = eSCI_A.SDR.B.RDTD; /* Read byte of Data*/

RecData = SIU_GPDI[104];
while (eSCI_A.IFSR1.B.TDRE == 0) {} /* Wait for transmit data reg empty = 1 */
eSCI_A.IFSR1.R = 0x8000; /* Clear TDRE flag */

}

Is this the correct way to use GPIO pins for esci interface?

Thanks

Vrushali

[PetrS]

Hi Vrushali,

If you want to use the eSCI module then you need to configure pins for eSCI functionality.

No eSCI options are available for your selected pins. The eSCI_A is available e.g on GPIO89 and GPIO90.

The setting should be

SIU.PCR[89].R = 0x400;  // Configure pad for primary func: TxDA

SIU.PCR[90].R = 0x400;  // Configure pad for primary func: RxDA

And use the eSCI DR register for transmit and receive, not GPIO output/input registers.

You can refer to MPC5777C PinToggleStationery example (https://community.nxp.com/docs/DOC-328290) which configure the eSCI_A properly. See uart.c file for details.  

BR, Petr