futz
Active Member
EDIT: Never mind! I thought about it some more and realized I had my clock polarity wrong. Changed it and she works perfect!
I wrote this little function to send a byte out the SPI, copying the way I used to do it in assembler (which worked fine).
But it doesn't work. The byte in the receiving shift register appears to be shifted by one bit, and of course my 7-seg displays junk. If I remove the sspstat.BF test, it displays correctly, but doesn't work right (hard to explain).
The generated assembly code looks fine:
Here's the (working) asm code I ported from:
I wrote this little function to send a byte out the SPI, copying the way I used to do it in assembler (which worked fine).
Code:
void spi_out(unsigned char digit)
{
unsigned char junk;
sspbuf=digit;
while(!sspstat.BF);
junk=sspbuf;
}The generated assembly code looks fine:
Code:
52: void spi_out(unsigned char digit)
53: {
54: unsigned char junk;
55: sspbuf=digit;
008A 501F MOVF 0x1f, W, ACCESS
008C 6EC9 MOVWF 0xfc9, ACCESS
56: while(!sspstat.BF);
008E A0C7 BTFSS 0xfc7, 0, ACCESS
0090 D7FE BRA 0x8e
57: junk=sspbuf;
0092 50C9 MOVF 0xfc9, W, ACCESS
0094 6E20 MOVWF 0x20, ACCESS
58: }
0096 0012 RETURN 0Here's the (working) asm code I ported from:
Code:
spisend movwf SSPBUF
BANKSEL SSPSTAT
spiloop btfss SSPSTAT,BF
goto spiloop
BANKSEL SSPBUF
movf SSPBUF,W
return
Last edited: