The micro-code in the HJS22 is implemented in five MM5203Q chips. To program these chips I had to built a programmer.
Here are some pictures of the programmer:
Programmer front side        Backview programmer

Left side detail        Middle view detail       Right side detail

In 1976 I didn't had a PC so I had to program all 256 location by hand. One mistake and I had to erase the chip and start all over again.
The input and display of the programmer is octal, at that time I was unable to find a hex keyboard and hex displays.

One micro word is 40 bits. 8 bits for 'Next Address' and 32 bits to control the whole machine. 
There are two micro word formats: Normal and Branch determined by bit 23. (see red circle)

MC layout

Bit 23 = 0.      Bits 9 till 40 are defined as shown in the above figure.

Bit 23 = 1.      Bits 9 till 16 form together the next micro word address if the condition selected by bits 17 - 20 is true.
                       If the condition is false the next micro word address is taken from bits 1 - 8. 
                       Bits 22 and 24 till 40 are ignored. (must be all zero.)

This pdf file  (5 Mbyte) contains scanned pages of the hand writen micro code.
Pages 1 - 4     Detailed description micro-word layout.
Page 5            High level flow chart of the micro code.
Pages 6 - 13   8 pages micro code.

Monitor Program