Re: [ECOS] MPC8xx SMC serial problem

[Will Wagner <will_wagner at carallon dot com>]

Will Wagner wrote:
> Hi All,
>
> Been testing serial comms with parity enabled. Always get the data sent 
> but occasionally (~25%) I get spurious data as well.
>
> Looking at it in the debugger it appears the buffer descriptor doesn't 
> hold valid data but it is being passed to the driver anyway. The control 
> flags of the buffer descriptor show that there has been a parity error 
> but this is never checked in the function quicc_smc_serial_DSR, it only 
> checks that the buffer is ready for processing not that there wasn't an 
> error.
>
> I think a change like this would fix the problem:
>
> while (rxbd != rxlast) {
>     if ((rxbd->ctrl & (QUICC_BD_CTL_Ready | QUICC_BD_CTL_Frame | 
> QUICC_BD_CTL_Parity)) == 0) { // Check if data error
>         for (i = 0;  i < rxbd->length;  i++) {
>             (chan->callbacks->rcv_char)(chan, rxbd->buffer[i]);
>         }
>
> Also need to add QUICC_BD_CTL_Frame & QUICC_BD_CTL_Parity to the list of 
> defines in ppc8xx.h
>
> Does this make sense? Has anyone else seen this problem? Presumably need 
> to apply the same change to the SCC DSR?

Think I have worked out the root of my problem. SMC is incorrectly 
configured if any parity enabled or stop bits is greater than 1. The 
field CLEN in SMCMR is being loaded with an incorrect value.

Looks like its going to be quite a substantial change, I'll submit a 
patch if I can get it working.

> Will.

--
------------------------------------------------------------------------
Will Wagner                                     will_wagner@carallon.com
Senior Project Engineer                        Office Tel: 0207 371 2032
Carallon Ltd, Studio G20, Shepherds Building, Rockley Rd, London W14 0DA
------------------------------------------------------------------------


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