I have problems connecting XICORS serial EEPROM X25040 to the 16c74.
The connections are as follows:

EEPROM   PIC
======================
SI   <-   SDO
S0  ->   SDI
SCK <-> SCK

On the EEPROM:
/HOLD  pull-up +5V
/WP pull-up +5V
/CS connected via a multiplexor

I also have a AD-converter(MAXIM) connected to the SPI-bus and that works
just fine.
The problem is to get in contact with the EEPROM. It just sends #ff, no
matter what I send.
Here is the code that I use to read the status register on the EEPROM.
_RB0-_RB3 is connected to a multiplexor and generates /CS allright. I
really have no idea what is wrong, since it works fine with the AD I don't
think it's software problem but I'm not sure. When I measure on the bus the
signals from the PIC seems to be OK (SDO,SCK and /CS) but the SDI is just
dead.
It's probably a silly mistake made by me (I use to do such mistakes) but I
just can't find it.

Init_SPI        movlw   0x21
               movwf    SSPCON

                bcf     _rp0
                bsf     _RB0            ;CS Serial EEprom
                bsf     _RB1            ; - " -
                bcf     _RB2            ; - " -
                bsf     _RB3            ; - " -
                movlw   B'00000101'     ;Read Status
                movwf   SSPBUF
                bsf     _rp0
loop    btfss   _bf     ;Wait until buffer full
                goto    Stest_loop      ;   -" -
                bcf     _rp0
                movfw   SSPBUF          ;read status
    movwf  TEMP


E-mail:Patric.Anvegard@fchv.hv.se