Re: TCP probems after changing clock speed on AT91RM9200

> Hi all,
> We've been developing an application on our own board which is based on the
> AT91RM9200. The eCos config is closely based on that for the AT91RM9200-EK
> and this has been going well for quite some time.
>
> We now tried to reduce the processor clock speed for power consumption
> reasons from180MHz to 90MHz and have run into a problem. The application
> appears to runs exactly as before (slower of course) and "normally"
> everything works fine. However,  we soon noticed a TCP related problem.
> After a lot of tracing it looks as if data sent on a TCP socket sometimes
> doesn't reach the remote end. Calls to fputs are made on the socket, and it
> returns an OK response, and then fflush is called on the socket so from the
> application it appears as if the data is sent successfully. At the remote
> end I just don't get the data.
>
> Now, this application has been running for months in the field (at 180MHz)
> without exhibiting any problems of this nature and now after halving the
> clock speed the fault occurs very frequently.
>
> I suspect the problem may be that I haven't configured everything in eCos
> correctly after changing the clock and this is causing some problems in the
> TCP/IP stack (I'm using FreeBSD network stackk by the way).
>
> To change the clock I simply changed CYGARC_HAL_ARM_ARM9_AT91RM9200_CLOCK to
> 90000000 (which forced CYGARC_HAL_ARM_ARM9_AT91RM9200_CLOCK is set to
> 30000000). As I said, the application "basically" runs OK except for my
> networking problem.