> -----Original Message-----
> From: Graham North [SMTP:graham.north@CIRRUSRESEARCH.CO.UK]
> Sent: Thursday, February 06, 2003 9:36 AM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      [PIC]: Using Timer 2 as clock for SPI?
>
> Hi everyone,
>
> How exactly do I use Timer 2 as the clock source for SPI? I am using a
> 17C756A, but guess it will be similar on other micros. Does the clock
> toggle
> every time the timer 'ticks', or only when the timer rolls over and
> generates an interupt? The data book does not describe it well.
>
> I am trying to get an ~2.5MHz clock speed for my SPI link with a 20MHz
> xtal,
> can it be done?
>
I'm not fammiliar with the 17C series, but in the 16x the SPI clock can be
derived from Fosc/4, Fosc/16, Fosc/64 or Timer 2 output/2.  The timer
outputs a clock when TMR2 matches the value in PR2, when the TMR2 register
is reset.  Thus a lower value in PR2 will give a faster clock rate. The
datasheet should give full details on the operation of the Timer2.

Regards

Mike

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads