When I got my Bachelor's degree, we had a microprocessor lab that had a microprocessor kit with a keyboard that had hex numbers 0-9,A-F, and a few control keys

When I got my Bachelor's degree, we had a microprocessor lab that had a microprocessor kit with a keyboard that had hex numbers 0-9,A-F, and a few control keys such as load, reset, etc. To program the device, we wrote the program in assembly, looked up the corresponding hex opcodes and operands and basically did an assembler's job. The result was a bunch of hex codes that we loaded and executed. I'm guessing these codes are similar, and there's a lookup table of codes somewhere?