Hi again,
I'm trying to implement an autobaud usart routine. My ideea was to change
the spbrg value register if a frameerror occure. The result is
interesting. It work's ok if I switch only from 57600 baud to 19200 baud
but if I want to use more than two different baud rate ( ie: 57600, 19200,
9600, 4800, 2400, 1200 ) by counting how many frameerrors appears and
change spbrg value (and brgh if necessary ) does not work. Here is my
frameerror routine, I know is not the best way to check the counter, have
some positive ideeas ?
How could be treated an overerror?

Thank's, Vasile

frameerror:                     -- if garbage is coming in
        bcf     intcon_gie      -- disable interrupts
        btfsc   intcon_gie
        goto    frameerror      -- be sure; still necesary ???
  --    movf    f877_rcreg,w    -- reading rcreg clears ferr flag
        bcf     f877_rcsta,ferr -- sure clears ferr!!!
        incf    counter,f       -- count how many frame errors take place
        movf    counter,w
        sublw   2               -- test if counter > 2
        btfsc   status_c
        goto    b_57600         -- if no try again with other baud rate
        clrf    counter         -- if yes reset counter and again
b_57600:
        movf    counter,w
        btfss   status_z        -- test if counter==0
        goto    b_19200          -- no, go to another baud rate
        movlw   10              -- yes, let the baudrate unchanged
        goto    set_spbrg             -- brgh is still high
b_19200:
        movf    counter,w
        sublw   1
        btfss   status_z        -- test if counter==1
        goto    int             -- if no, go to ser_in
        movlw   31              -- if yes set baudrate 19200
        goto    set_spbrg
b_9600:
        movf    counter,w
        sublw   2
        btfss   status_z        -- test if counter==2
        goto    int             -- if no, go to ser_in
        movlw   64              -- if yes set baudrate 9600
set_spbrg:
        bcf     status,6
        bsf     status,5        -- bank1
        movwf   f877_spbrg      -- load spbrg with new baud_rate
        bcf     status,5        -- bank0
int:
        bsf     intcon_gie      -- enable interrupts
        goto    ser_in

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