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help needed on MPC860SAR serial ATM interface

From: xlpeng@my-deja.com
Date: Sun, 16 Apr 2000 23:28:10 GMT
Organization: Deja.com - Before you buy.
X-Article-Creation-Date: Sun Apr 16 23:28:10 2000 GMT


Hi all,

Here is my problem on MPC860SAR serial ATM interface:

When I configure MPC860SAR serail ATM interface using NMSI mode SCC4(the
only interface has been used in my design), and I use sample driver
from   motorola(aalx_sar.c). When I do internal loopback, everything is
fine. When I test with real ATM line, I can see idle cells coming out,
but for the receive side, lots of problems.
1) According to the manual, I use FPGA to generate a /CD pulse every
   byte, if I don't set the COSET bit in PSMR, the sample driver
   (aalx_sar.c) will declare that the SYNC(cell delineation) is
   accquired, but soon it will say that the SYNC is lost. This will be
   repeated endlessly.
2) If I set the COSET bit, the program only goes into interrupt once
   and declares that the SYNC is accquired. After that, I will not get
   any interrupts at all.

I think I configure the SCC4 correctly, and /CD pulse is one clock
period low for every byte. Why there is such huge difference with
COSET bit set/unset.

Also for the transmit side, only idle cells coming out, the data in
transmit buffer is not transmitted.

Any suggestion will be preciated.

Best regards,

Leland Peng


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