Thanks John,
I could probably do just that by having inline code to decode and store
all 4 characters and then process them at the end. I just wonder what
the processing time might be before I will be online again waiting for the
next transmission. I'll definitely look into that possibility. If there are
resonators available at say 100kHz or so I could still leave it running
based on the published current specs and have more processing cycles.
The lowest frequency I have seen is 455 kHz though... (AM IF filter resonators)

After reception I have to dig out the information which is hidden in the 4 chars
and find out if I am the addressee, in which case I must act on the data.
The bits are scrambled to make it work with a simple logic circuit (3 bits are
stuffed into each character) so I have 12 bits of real info here. 8 bits are a
unit address and 4 bits are actual data.
With the new circuit I want to also expand on the coding so i might add some
more codes - giving more things to decode.
Well, I just have to figure out the best way I guess...

Cheers!

Bo Berglund
PaddelvŠgen 10, S-17545 JŠrfŠlla, Sweden
e-mail: bo.berglund@mailbox.swipnet.se


----------
From:   John Payson[SMTP:supercat@MCS.COM]
Sent:   den 25 maj 1997 13:52
To:     PICLIST@MITVMA.MIT.EDU
Subject:        Re: Wakeup time from sleep on 16C84???

> The reason for the low clock speed is that I MUST get the thingie
> to use as low current as ever possible. If I look in the data sheet
> it seems like the curent consumption is approx proportional to
> the clock rate, hence this low clock freq.
> I am trying to replace an EPLD logic circuit with the PIC16C84
> and the requirement is that operating current has to be below
> 500 uA. With the sleep trick I can probably get it down there as
> average current because of the low signalling duty cycle.
> But I think that 10 MHz clock will raise current too much.
> Code packets consist of 4 chars at 1200 baud which effectively
> keeps the PIC out of sleep for about 33 ms.

I don't know what else your application is doing, but might it be possible
to use a 32KHz PIC and just leave it running all the time?  1200 baud is
possible on such a device of you're not doing anything else while waiting
for a character.  If you had an interrupt on the start bit, you may even
be able to do other processing while waiting for characters but I've never
done it that way.