On 23/07/2016 20:08, Segher Boessenkool wrote: > Why do you think you can set all port bits on the 8500? Interestingly the preliminary 6510 datasheet has a different pinout that includes all 8 bits on the io port. http://archive.6502.org/datasheets/mos_6510_mpu_nov_1982.pdf The later datasheet lists three chips (6510, 6510-1 & 6510-2). The former is the c64 pinout, the other two have all 8 bits on the io port. http://archive.6502.org/datasheets/mos_6510_mpu.pdf So at least on the 6502, I would expect it to be a bond out issue. However If you can't read back what you've written to outputs then the sense lines aren't connected to the output buffers, or there may not be output buffers on the missing bits. It would seem odd for them to create masks for each pin configuration, but then we don't know that these chips were even produced. Message was sent through the cbm-hackers mailing listReceived on 2016-07-23 22:00:19
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