[U-Boot-Users] Fixed CD in serial.c, AT91RM9200

[U-Boot-Users] Fixed CD in serial.c, AT91RM9200

[Kögler Peter]

Hello all,
is there a reason why the clock divisor in the baudrate generator register
(us->US_BRGR) is set to a fixed value in serial_setbrg(void):

us->US_BRGR = CFG_AT91C_BRGR_DIVISOR


I changed the implementation of serial_setbrg(void) and i can now opperate
at higher baudrates. (change baudrate with loadb).

Here is my version:

void serial_setbrg (void)
{
  DECLARE_GLOBAL_DATA_PTR;
  int baudrate, baudRateGenDiv,i;
  unsigned long baudrate_table[] = CFG_BAUDRATE_TABLE;
  int n_baudrates = (sizeof(baudrate_table) / sizeof(baudrate_table[0]));

  baudrate = gd->baudrate;
  
  //check if value is supported
  for (i=0; i<n_baudrates; ++i) 
  {
    if (baudrate == baudrate_table[i])
    {
      baudRateGenDiv = AT91C_MASTER_CLOCK / baudrate / 16;
      //printf ("## Switched baudrate to %dbps.\n", baudrate);
      break;
    }
  }
  
  if (baudRateGenDiv==0)
  {
    //using default value
    baudRateGenDiv = CFG_AT91C_BRGR_DIVISOR;
    printf ("## Baudrate %dbps not supported using default baudrate
%dbps.\n", baudrate, CONFIG_BAUDRATE);
  }
  
  us->US_BRGR = baudRateGenDiv;
}

If you agree with my changes i can provide a patch.

wbr

Peter

[U-Boot-Users] Fixed CD in serial.c, AT91RM9200

[Wolfgang Denk]

In message <367ED8C46538D7119DAC000A0D106744520D6E@elmegmbh.elmedmn.com> you wrote:
> 
> is there a reason why the clock divisor in the baudrate generator register
> (us->US_BRGR) is set to a fixed value in serial_setbrg(void):
> 
> us->US_BRGR = CFG_AT91C_BRGR_DIVISOR
> 
> 
> I changed the implementation of serial_setbrg(void) and i can now opperate
> at higher baudrates. (change baudrate with loadb).

I have never seen any feedback or comments about this proposal.


Anybody out there?


Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
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Million Miles Per Hour.

[U-Boot-Users] Fixed CD in serial.c, AT91RM9200

[Steven Scholz]

Wolfgang Denk wrote:

> In message <367ED8C46538D7119DAC000A0D106744520D6E@elmegmbh.elmedmn.com> you wrote:
> 
>>is there a reason why the clock divisor in the baudrate generator register
>>(us->US_BRGR) is set to a fixed value in serial_setbrg(void):
>>
>>us->US_BRGR = CFG_AT91C_BRGR_DIVISOR
>>
>>
>>I changed the implementation of serial_setbrg(void) and i can now opperate
>>at higher baudrates. (change baudrate with loadb).
> 
> 
> I have never seen any feedback or comments about this proposal.
> 
> Anybody out there?

I introduced this since it was originally hardcoded to

	us->US_BRGR = 33

for the AT91RM9200DK. The comment says "hardcode so no __divsi3".
I decdided that having a CFG_AT91C_BRGR_DIVISOR in your board specific 
header file would be enough.

I had no time to test Peter's patch yet. But go ahead and apply it. If I 
find problems I'll report them...

-- 
Steven Scholz

[U-Boot-Users] Fixed CD in serial.c, AT91RM9200

[Wolfgang Denk]

In message <410F7832.8070700@imc-berlin.de> you wrote:
> 
> I introduced this since it was originally hardcoded to
> 
> 	us->US_BRGR = 33
> 
> for the AT91RM9200DK. The comment says "hardcode so no __divsi3".

This is what I remember, so I guess there was a problem?

> I had no time to test Peter's patch yet. But go ahead and apply it. If I 
> find problems I'll report them...

Ummm... please test it first, to avoid  checking  in  something  that
doesn't work. Thanks.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
No problem is insoluble.
	-- Dr. Janet Wallace, "The Deadly Years", stardate 3479.4