SAC INTERFACE FOR ADDING PERIPHERALS TO THE 1130
My cleanup of the logic continued at lunch, with solid results at each stage once I fine tuned the VHDL. The problem I was shooting at the end of the lunch hour was failure to reliably store the SAR.
The low order bits of the SAR were updated by the 'increment by one' operation I specified in the VHDL, but the higher bits were dropping. I loaded 0x0100 as an address and began writing sequentially to the location, but bit 7 dropped out.
I continued in the early evening, hammering away at the logic. It is not working up to my expectations yet. I won't bore everyone with blow by blow descriptions of each test and solution, but will wait until I get a totally satisfactory completion when testing the major functions.
SUBSTITUTE SOLUTION FOR DISK CARTRIDGE CLEANING MACHINE
The disk drive maintenance manual describes manual cleaning as a process of using isopropyl alcohol to dampen but not soak lint free clothes which are wiped on the disk surface. Thus, I can use 99% isopropyl alcohol as my cleaning solution but I must get the machine adjusted so that it keeps the pads barely wet. No rush to work on the machine but I am happy that there is a clear path to putting it back into service.