HDLC Synchronous RS232

Have you turned the transmitter on?

hi,

thanks for your response.

i have enabled the transmitter using the Enable Transmit(ENT=1)in GSMR register.

is it what u r saying or is there anything else i had to do to start the transmitter? please get back to me with some hints.

thanks

Lanarcam wrote:

Have you studied thoroughly the HDLC configuration examples in the manual (chapter 7.10.17.14 and 7.10.17.15 at least in the original manual).

The QUICC co-processor is quite complex. Do you have any previous experience of using the SCC ports as UARTs ? If not, I would suggest that you first try make the interface work as a UART before attempting to set it up as HDLC.

Paul

Are you seeing flags on your TX line ? 0x7F at whatever bitrate you are using. If the transmitter is enabled, HDLC mode selected you should see 0x7F on the TX line. If not, then either you have not enable HDLC mode, or TX is disabled ot you have selected to not have flags in idle mode.

Regards Anton Erasmus

hi, thanks for your response. as you have said iam able to see the 0x7f on the TXD line after the Transmitter is enabled. my only problem is iam not able to see the clock signal on the TXCLK line.

I have set the PAPAR reister to all 1's i.e PAPAR = 0xffff

PAODR = 0x0000; PADAT = 0xffff; PADIR = 0x0000; PAPAR = 0xffff;

is there any problem with the above register settings?

In the current scenario iam initializing BRG4 to 19.2 kbps and using it for the ports SCC2 and SCC3

BRGC4 = 0x020000; BRGC4 = 0x0100a2;

SICR &= 0xff0000ff; SICR |= 0x001b1b00;

can u pls check my above settings for SICR and BRGC registers and see if iam doing it right?

thanks,

Ant> >

Flags are 01111110, i.e. 0x7e.

hi,

yeah flags are 0x7e u r right it was a typing mistake.

thanks

As has been pointed out the flags are 0x7E.

I do not have the MC68360 docs handy, hence cannot check the detail. In general you should look at the baud rate generator settings. It should be possible to output this clock on a pin regardless of what mode the SCC is in. Setting up the pins to output the signal you want is probably descriped in a different section from where the SCC is described. You probalby need to set up some registers that has something to do with selecting either an alternative function for a pin or using it as a general purpose I/O.

Regards Anton Erasmus