Sleep() & Interrupts - SOLVED

[Gabriel]

Hi all,

Project: datalogger
PIC: 16f876A
RTC: DS1305
Memory: 25LC256

when my code puts the pic to sleep, after some time RTC Alarm wakes the pic, operation resumes, PIC does its thing and goes back to sleep.

my understanding is that when the pic is in sleep any interrupt will wake it up.
The RTC alarm is using INT_EXT and it works fine.

i want to be able to wake the PIC using the INT_RDA as well.

i sent characters to the pic while it was sleeping and nothing happend.
which to me it means that the pic is not waking up and that the character i send is not even triggering the INT.

is this normal?

Thank you for your help
_________________
CCS PCM 5.078 & CCS PCH 5.093

[Wayne_]

Looking at the data sheet:-

"10.2 USART Asynchronous Mode"

"Asynchronous mode is stopped during Sleep."

[Gabriel]

hi Wayne_

i found this thread doing some further research:
http://www.ccsinfo.com/forum/viewtopic.php?t=36125&highlight=waking+rda

i believe your answer is closely linked to the topic discussed in the thread above...

.... any workarounds?

thanks for your help.
_________________
CCS PCM 5.078 & CCS PCH 5.093

[Wayne_]

They are different chips, the 6722/8722 will wake up on transition off the RX signal, the 16f876A will not.
The 16f876A will however wakeup if you use synchronus mode because it can still clock in the data and will interrupt upon reception of the data.

Workarounds consit of, connect the RX input to an EXT_INT pin or use a different chip.

[Gabriel]

[bkamen]

consider putting 'SOLVED' in the subject of the first post so it shows up in the topic list.

cheers,

-ben
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D

[Gabriel]

sorry... that was my intention... i spaced out and put it on the wrong part..
_________________
CCS PCM 5.078 & CCS PCH 5.093