HP-71B Auto on

[J-F Garnier]

(02-10-2023 09:03 AM)brouhaha Wrote:  

(02-10-2023 08:11 AM)J-F Garnier Wrote:  So it seems there are some hardware variations of the HP-IL module 1B.

There's a microcontroller in the -71 HP-IL module, which provides the mailbox interface to the Saturn bus. The microcontroller has firmware in masked ROM. It's possible that it was revised, without requiring a change to the 1B Saturn ROM. There's probably a way to interrogate the microcontroller ROM version through the mailbox.

The microcontroller is described in the HP-IL IDS as a "CMOS chip with cycle time of 1u sec, 272 bytes of RAM and 4096 bytes of ROM". 131 RAM bytes are used for I/O buffers.
There are diagnostic commands to perform a RAM/ROM self test with just a OK/NOK result, and to read/write RAM locations. No way to get a firmware version or read the ROM (or if there is, this is undocumented).

J-F