Ian Chapman wrote:

> Are you relying on the internal RC oscillator rather than an external
> crystal or ceramic resonator?  If so, then it may not be up to the job.
> Table 17-4 in my copy of the PIC16F62X data sheet shows a range of
> 3.65MHz to 4.28MHz for INTRC mode, i.e. -8.8% to +7.0% of the nominal
> 4.0MHz.  For reliable serial communication, timing accuracy of better
> than +/- 3% is typically required.

Too true.

I have done some work with the 628 UART using the internal osc. I found
I could reliably transfer at 9600 baud only if I send - byte (ACK) -
byte (ACK) etc..

Sending multiple bytes in a packet did not seem to work well.


--
Best regards

Tony

mICros
http://www.bubblesoftonline.com
mailto:sales@bubblesoftonline.com

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