I have an old keyboard that uses an 8051AH IC along with a HC14, a HC14T and 3 74HCT4051 IC's.
I am trying to rebuild part of this (not all of it) and have the circuit diagrams for the keyboard.
I don't need the 40 pin version (as used in the keyboard)as I do not require all the inputs ( so I was wondering if I can just replace it with a 89c2051.
I know the 8051AH is factory programmed ROM - I presume this is from the IC manufacturer and not the hardware manufacturer into which it is installed.
With that in mind, will I need to program the 89c2051? And if so, will I be able to read and copy the programming from the old 8051AH with suitable PIC equitment?
Or is it literally a plug an pray drop in replacement?
Most helpful, thank you.
Your right about the quadrature nature of the mouse and the 3 button signals. They use 7 of the 9 pins available in the mouse leaving GCC and Gnd.
The keyboard, unlike PS/2 (which sends data and clock) sends tx and RX.
I will pay with salvaged chips I think.
Regards, Jon.