Instant Interrupts - Revisited

[Darrel Taylor]

I assume you meant 16F886?

From the datasheet...

During Sleep mode, all clocks to the EUSART are
suspended. Because of this, the Baud Rate Generator
is inactive and a proper character reception cannot be
performed.

You can use the AUTO-WAKE-UP ON BREAK feature of the EUSART, but there are several things to consider.

Take a look at section 12.3.2 AUTO-WAKE-UP ON BREAK
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[jchandir]

shoot.. i meant 16f688... sorry about my careless mistake.

[jchandir]

ok so i solved the problem. thanks Darrel. I just had to set the BAUDCTL.1 (WUE) bit.

[Darrel Taylor]

I'm not sure if you read the whole 3 pages worth of information on Auto-wake-up on break, but it'll take a little more than flipping a bit.

The transmit side needs to send the right character (0), or a Break sequence, to wake-up the PIC or you will loose at least the first character and get a framing err (FERR), and possibly a buffer overflow (OERR).

The second character can also be lost if time is not allowed for the oscillator to stabilize.
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