Re: [lwip-users] cs8900 stall

[Chris Hiszpanski]

Hi Peter,

Are you refering to the issue where the cs8900 will eventually miss an 
interrupt if it is in 8-bit mode? This is not a problem for me since I have 
my hardware configured for 16-bit accesses.

I also found a possible cause in the Cirrus Logic an205-2 application note 
for the cs8900. Apparently, before skipping a frame, RxLength and RxStatus 
must be read, which the driver does not seem to do. Adding these changes to 
the driver did not fix the problem however. I added:

PACKETPP = RXSTATUS;
temp = PPDATA;
PACKETPP = RXLEN;
temp = PPDATA;

before every Skip_1 (four places in the file).

One more thing I noticed. In cs8900if_init, I had cs8900if->use_polling = 
1;. I changed this to 0, but this only made matters worse. With that change, 
all pings to the board failed. In fact, the interrupt line is never driven 
high.

Cheers,
Chris

> > Essentially, if the cs8900 receives an addition packet while a packet is 
> > waiting to be processed by an interrupt handler, the cs8900 stalls.
> >
> > Is anyone else experiencing this problem?
>
> I don't know if it's _this_ problem, but I remember several years ago the 
> CS8900 had a hardware problem concerning lost interrupts, and I had to add 
> polling to keep it alive. (Not under lwIP though.)
>
> Maybe check the chip errata, wether this problem still exists.
>
> All the best
> Peter

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