I can't get the SPI programming to work on my AT89S8252 part. I'm using my LPT port and a 74244 OCT/BUF line driver to drive the SPI and RST pins. I've verified, using a voltmeter, that I'm able to individually toggle the SCLK, MOSI and RST pins on the MCU. I've also verified that the I'm correctly reading the MISO pin. I set RST hi, send the programming enable command (0xAC, 0x53,0xXX), send a write code command to write 0 to location 0 (0x02,0x00,0x00), then I read back location 0 (0x01,0x00,I Read MISO) and I get 0xFF, not 0x00. I've also tried writing to data memory with the same results. I've tried LSB first, MSB first, they all fail. I thought that maybe I had a problem with my programming algorithm so I created an application with three buttons, one to toggle CLK, one to toggle MOSI and one to read MISO. I used these buttons to manually clock in the commands and I'm still unable to program the part. I've tried using a different AT89S8252 but the results were the same. The parts are new and have never been programmed before. I'm stumped! Does anyone have any ideas whats wrong? Any help would GREATLY be appreciated.

Thanks,
Mike Payne
Mpayne@austin.rr.com