Nut 1LQ9 pinout?

[hjalfi]

I just picked up a 1994 Singaporean HP-12C from a local shop which sells things that people have lost on the train. It cost me five francs (== $5). Nice!

If I take the lid off, I can see the single chip which runs it, a Nut 1LQ9-0322. Looking around I can see that the two-chip version of this uses the 1LQ9-0325. I also see that this is the same PCB (5180-1516) as the 15C, which is a two-chip calculator.

Which I find very interesting. There is an unpopulated footprint, presumably for the 1LH1 ROM for the 15C (although it's weird. Half the pins are either grounded or not connected). But there are also a lot of possibly unused pins on the CPU package itself.

Does anyone have the pinout for the 1LQ9? And the 1LH1 would be handy, too. I have vague ideas about building an external memory interface for this. It'd be fun to run Nut machine code programs for it...

[brouhaha]

(05-13-2024 10:15 PM)hjalfi Wrote:  I just picked up a 1994 Singaporean HP-12C from a local shop which sells things that people have lost on the train. It cost me five francs (== $5). Nice!

If I take the lid off, I can see the single chip which runs it, a Nut 1LQ9-0322. Looking around I can see that the two-chip version of this uses the 1LQ9-0325.

No 12C uses a 1LQ9-0325. That is ONLY used in the 15C. The 1LQ9-0325 contains half of the 15C ROM, with the other half in the 1LH1-0302.

The common PCB for 1LQ9 calculators has room for a 1LH1-0302 for the 15C, but the 1LQ9-0322 used in the 12C doesn't have the external bus interface. It is disabled either in the mask programming, or (possibly) by pin-strapping.

The 1LH1 pinout may be the same as the 1LE2, but I have not verified that.

[hjalfi]

I've done some poking with an oscilloscope and have identified the LCD pins and the keyboard pins, which is most of them, but there is definitely activity on the pins which go to the unpopulated ROM pad. Chances are that this doesn't mean anything, but it'd be interesting to investigate anyway.

I see that Eric Smith (is this you?) has tooling for reading the ROMs by monitoring the bus traffic as the machine does a ROM self-test, which means that the chip pinout must be known, but I can't find any documents or software describing how the rom sucker works. Is this available anywhere?

(Also, I notice that gallery.brouhaha.com seems to be down.)

[brouhaha]

I was not able to get any data out of the 1LQ9-based 12C, and didn't try the other 1LQ9 models. It's possible that I may have failed to probe the right pins.

At the time (back in 2004), I had partially figured out the pinout of the 1LF5 CPU (might match the later 1LM2), and the 1LE2 R2D2 (with LCD drive), but neither of those will match the 1LQ9 or 1LH1.

The only pins I wired for dumping Voyager firmware were the phase 1 and phase 2 clocks, ISA, and SYNC signals. The phase 2 clock wasn't really necessary for the ROM dumping.

For what it's worth, from my notes on the 1LF5 CPU:

The 1LF5 is in what would be a 44-lead QFP, except that there are missing pins. Only 27 pins are actually soldered to the board. The center pin on each package side protrudes from the molding but is too short and does not have the gull wing lead form to be soldered to the PCB. I think those four pins are grounds. Looking at the PCB in the obvious orientation, the 1LF5 pin 1 dimple is at the lower left. Numbering pins (including missing pin locations) counterclockwise from the bottom left pin, 1 is the phase 1 clock, 2 is the phase 2 clock, 37 is SYNC, and 44 is ISA.