HPIB Stuff - some capture stuff

Tony Duell ard at p850ug1.demon.co.uk
Sun May 4 15:29:59 CDT 2008

> Talk to me about the HP150. What HPIB chip does it use? Does your

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. 

> version of DOS/UNIX have the tools that you need to do register level

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.


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