While the box, which I labelled, contained Intel samples of i8751H-12's and multiple rails of AMD 8751H's. The latter, the AMD parts, worked as one might expect, once 10K-ohm pullups were put on P0, AND the oscillator was reduced to below 10 MHz. It did not function above 10 MHz, nor did it function without the pullups, even when HCT latches on P2 and P0 were used. The latch on P2 functions simply as a buffer. I didnt' have LS573's on hand, so that wasn't attempted. It puzzles me that the HCT logic didn't work with the AMD parts. Oddly enough, the Intel parts, which also didn't work without the pullups, using AC logic, DID work with the HCT latches. It was no surprise that the Intel parts work at 12 MHz.

Neither the Intel parts nor the AMD parts get hot when they are running. Because the AMD parts don't work at 11.0592 MHz, I wasn't able to verify that they operate properly, i.e. the debugger didn't talk to the terminal. I could change the parameters in the code, I guess, but I'm not that interested.

I also found that the oscillator pins seem to work different ly between these purportedly similar parts. The AMD part works fine when pin 18 is grounded, as shown in the datasheet, but doesn't function when it's open (driving XTAL1 with an oscillator). The Intel parts seem to work either way.

RE