ROM hex files for the HP 5335A Universal Counter.

These files were pulled from a SN 2220 Counter but will work in any version. 
The files are included in both Intel and Motorola format to cover a wide variety of EPROM programmers.
24-pin 8Kx8 (64K) 450ns ROMs are difficult to find and burn so you will need to make an adapter and use 2764 28-pin EPROMs. 


These two files are in Intel format and came from 2364 ROM chips in positions U22 and U23.
The HP part numbers are 1818-12xx in the files.

U22_2364_intel_format 1818-1249.hex
U23_2364_intel_format 1818-1250.hex


These two files are in Motorola S format and came from 2364 ROM chips in positions U22 and U23.
The HP part numbers are 1818-12xx in the files.

U22_2364_motorola_format 1818-1249.hex
U23_2364_motorola_format 1818-1250.hex


A later version 1.1 was produced that has some improvements in HPIB support and general performance fixes.