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I'm trying to write SPI Master code to send from a 16F628 to a MAX7219. Anybody got any example code? I've written what I think should work, but no luck so far. I have a logic probe and can see the MOSI, CLK and SS lines toggling away, but the 7219 doesn't react. A scope would be awesome right now, but I don't own one. Here are the Init and Transmit sections of my code (periods are to hold formatting). If you see anything that seems wrong, please tell me: init: ........bsf........STATUS,RP0........;bank 1 ........movlw......b'00000000'.......;set PORTB all outs ........movwf......TRISB ........movlw......255...............;set baud rate ........movwf......SPBRG ........bcf........STATUS,RP0........;bank 0 ........movlw......b'11111000'.......;turn off LED's & set SS high ........movwf......PORTB ........bsf........RCSTA,SPEN........;set SPEN ........bsf........STATUS,RP0........;bank 1 ........movlw......b'10110010'.......;set SYNC,CSRC and TXEN ........movwf......TXSTA ........bcf........STATUS,RP0........;bank 0 transmit: ........bcf........PORTB,3...........;lower SS ........movf.......regbyte,W.........;load register byte ........movwf......TXREG.............;transmit it ........bsf........STATUS,RP0........;bank 1 send1:..btfss......TXSTA,TRMT........;transmission done? ........goto.......send1.............;no, then go again ........bcf........STATUS,RP0........;bank 0 ........movf.......databyte,W........;load register byte ........movwf......TXREG.............;transmit it ........bsf........STATUS,RP0........;bank 1 send2:..btfss......TXSTA,TRMT........;transmission done? ........goto.......send2.............;no, then go again ........bcf........STATUS,RP0........;bank 0 ........bsf........PORTB,3...........;raise SS to latch data ........return.......................;yes, done |
assembler SPI on 16F628 to MAX7219
Started by ●May 8, 2003
