At 09:31 AM 1/6/03 -0500, you wrote:
> > I was recently reminded that some of the older PICs (eg. PIC16C73) have
> > the "high speed mode" (BRGH = 1) but it doesn't work properly.
>
>Really?!  I hadn't heard that before.  I used a 16C77 in several project a
>few years ago and the high speed mode worked fine with a 20MHz oscillator
>and 115.2Kbaud.  I would think that the 73 and 77 would have the same
>USART silicon.

Doesn't appear so. Here's the errata for the C73 Rev. A and the C77
Reva. A., no mention of the problem in the latter. Note that the C73
is obsolete, replaced by the C73B (which fixes the problem), but
lots of us have them still kicking around (two JW's for me).

http://www.microchip.com/download/lit/suppdoc/errata/er16c73.pdf

"When the USART (SCI) is configured in asynchronous
mode with the BRGH bit set, a high number of
receive errors may be experienced. For asynchronous
receive operations, it is recommended that the
USART be configured with the BRGH bit cleared."

http://www.microchip.com/download/lit/suppdoc/errata/80091a.pdf



Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu