HDLC Synchronous RS232

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hi all,

 iam currently programming MC68360 board processor SCC's to work for
Synchronous HDLC and iam taking out RS232 pin outs from the P2
connector.

I have initialized the registers and set jumpers according to the
instructions. but iam not getting the Clock signals from the TXCLK
lines.
can u pls give me some hints what r the things that can go wrong which
will lead to this kind of problem.

thanks and regards,


Re: HDLC Synchronous RS232
Re: HDLC Synchronous RS232

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:
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Re: HDLC Synchronous RS232


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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
 

Re: HDLC Synchronous RS232

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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





Re: HDLC Synchronous RS232
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,

Anton Erasmus wrote:
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Re: HDLC Synchronous RS232

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As has been pointed out the flags are 0x7E.

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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


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Re: HDLC Synchronous RS232
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Flags are 01111110, i.e. 0x7e.

--

Tauno Voipio
tauno voipio (at) iki fi



Re: HDLC Synchronous RS232
hi,

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

thanks


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