Hi All,

I have the problem of transfering information between 2 pics using SPI. I
seem to be able to transfer 3 memory location from one to the other, but I
cannot trasfer a fourth. The code I am using is as follows:

                MASTER:

        call    select_2_mem_page
        movlw   0x11
        movwf   accelerating_lo_limit

        call    select_2_mem_page
        movlw   0x55
        movwf   braking_lo_limit

        call    select_2_mem_page
        movf    accelerating_lo_limit,0
        call    write_sspbuf
        call    select_2_mem_page
        movf    braking_mid_limit,0
        call    write_sspbuf
        call    select_2_mem_page
        movf    braking_hi_limit,0
        call    write_sspbuf

        call    select_2_mem_page
        movf    braking_lo_limit,0
        call    write_sspbuf
        call    select_2_mem_page
        movf    accelerating_mid_limit,0
        call    write_sspbuf
        call    select_2_mem_page
        movf    accelerating_hi_limit,0
        call    write_sspbuf

loop
        goto    loop

write_sspbuf

;writes the value in w to SSPBUF and wait for slave to read

        banksel SSPBUF
        movwf   SSPBUF
transmit_data
        banksel SSPIF
        btfss   PIR1,SSPIF
        goto    transmit_data
        bcf     PIR1,SSPIF
        delay
        return

                SLAVE:

        call    get_new_data
        call    select_2_mem_page
        movwf   accelerating_lo_limit
        call    get_new_data
        call    select_2_mem_page
        movwf   braking_mid_limit
        call    get_new_data
        call    select_2_mem_page
        movwf   braking_hi_limit

        call    get_new_data
        call    select_2_mem_page
        movwf   braking_lo_limit
        call    get_new_data
        call    select_2_mem_page
        movwf   accelerating_mid_limit
        call    get_new_data
        call    select_2_mem_page
        movwf   accelerating_hi_limit

loop
        goto    loop

get_new_data

;waitss for the interrupt ie new data has arrived in sppbuf
;then puts the data in w

        banksel SSPIF
        btfss   PIR1,SSPIF
        goto    get_new_data
        bcf     PIR1,SSPIF
        banksel SSPBUF
;       comf    SSPBUF
        movf    SSPBUF,0


At the beginning of the MASTER program I put a value in a memory location.
At the end of SLAVE I read this memory location and put it on portD.

This will work for the code above braking_lo_limit (ie portD is correct)
This will not work for the code below and including braking_lo_limit (ie
portD is incorrect)

What am I doing wrong???

Thanks,

Andrew Scott

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