HPIB Stuff - some capture stuff

It's a TMS9914 (I've just checked the TechRef), directly on the 8088 bus. In general HP's HPIB-capable computers of that vintage used the 9914. Some peripherals used the Intel 8291, others bit-banged the protocol using a microcontroller. Later computers used an HP custom chip called 'Medusa' IIRC. Earlier computers either used a microcontroller or discrete TTL chips. THe HP150, being an 8088 machine, has no hardware protection at all, and the TechRef gives the addreses for the 9914 registers (and tells you to look at the data sheet for said chip :-)). There is an MS-DOS device driver for it, which implelents a subset of the HPIB functions using ioctl() calls (basically, according to the manual, it only supports functions where the HP150 initiates the operation). One disadvantage of the HP150 for this is that it only supports one HPIB port. On the HP9000/200 machines you can have 2 or more HPIB interfacs, it's best to have one for you system disks, etc and the other for talking to the device you're hacking about with. That way, if you make a mistake you'll not corrupt your system disk. -tony