HP41C with Rp Pico attached

[rprosperi]

(02-19-2024 01:05 PM)MeindertKuipers Wrote:  Hello all,

After some time of developing and debugging I am now happy to announce that I have HP-IL emulation up and running ...

Amazing job Meindert. Just as I've noted for Thomas' related project, this is really impressive, an amazing accomplishment. It's quite remarkable to have created a module/device that provides so many powerful and useful features, 41 users of all types will want and appreciate one of these, we look forward eagerly for updates and a hopeful announcement that it will be made available.

And of course thanks are also due for other contributors, principle among them: Andrew, Christoph, Jean-Francois, and Thomas! Such work is never done alone, so the work of prior giant contributors is important and due.

[PeterP]

Mindbogglingly cool.

[Massimo Gnerucci]

(02-19-2024 04:39 PM)rprosperi Wrote:  41 users of all types will want and appreciate one of these, we look forward eagerly for updates and a hopeful announcement that it will be made available.

We really would!
Thanks to the team for all the research.

[floppy]

(05-31-2023 06:27 AM)blackjetrock Wrote:  This is a project that I have been working on. It is a RP Pico sitting on the bus of an HP41C. It can trace the bus traffic and dump to USB and can also drive the bus and hence emulate a module or modules. It can also enter programs by pressing keys on the keyboard. There's a small OLED display that mirrors the LCD. It is very much a work in progress, so for instance, the entered programs aren't quite right and I've only emulated the MATH module.

https://github.com/blackjetrock/pico41.git

Andrew

Sniffing then extending an HP12C bus would make it interacting with the external world?

[blackjetrock]

(03-15-2024 11:16 AM)floppy Wrote:  

(05-31-2023 06:27 AM)blackjetrock Wrote:  This is a project that I have been working on. It is a RP Pico sitting on the bus of an HP41C. It can trace the bus traffic and dump to USB and can also drive the bus and hence emulate a module or modules. It can also enter programs by pressing keys on the keyboard. There's a small OLED display that mirrors the LCD. It is very much a work in progress, so for instance, the entered programs aren't quite right and I've only emulated the MATH module.

https://github.com/blackjetrock/pico41.git

Andrew

Sniffing then extending an HP12C bus would make it interacting with the external world?

Hmm, in principle that could be done. I'm not very familiar with the 12C in terms of voltages and whether there is a bus inside that can be sniffed. There's a lot of emulators so I presume that the machine is well understood. If there is a sniff-able bus then yes, you could probably extend it with some scheme where a memory is re-purposed as a control and status location. Programs that wrote to that memory (a register, probably) would give instructions to the sniffer to do something, like send an I2C packet, or the sniffer would put the reply from external hardware in some other register.

I have done something similar with the casio FX502P, using the cassette port to interact with an attached processor.

https://youtu.be/JpELJASPR_0

I managed to attach a printer, which works by printing the program data that the 502P sends when saving a program to cassette tape.

https://youtu.be/e1qKueurD7A

[brouhaha]

(03-15-2024 11:16 AM)floppy Wrote:  Sniffing then extending an HP12C bus would make it interacting with the external world?

The bus is the same, though the LCD control is different. There are two registers at addresses 0x09 and 0x0a, which hold the bimap for the 100 software-controllable segments of the display, 50 bits per register. See "synthetic Methods on the HP-15C" by Allyn Tennant, though note that on the 10C the segment mapping is different.

There are also the same display off and display toggle instructions of the 41C family, but in addition, an instruction 0x030 that sets the display to flashing mode. (The display off instruction exits the flashing state.) The display flash timing is independent of the CPU, and in particular, do not start/stop or change the phase of the display blink timer based on any CPU instructions, including the display control instructions. If you do, you'll end up with incorrect displays of "running", either blank almost all the time, or active almost all the time without flashing.

For general interfacing or for duplicating the display, fundamentally you need the phase 1, phase 2, sync, ISA, and DATA lines. I've identified some signals on the 1LF5-0301 CPU used in early Voyagers, but not the DATA line. DATA should probably be the pin between GND and SYNC, but I haven't verified that. The 1LF5-0301 is in a modified 44-pin QFP. Many pins are missing, and some pins in the middle of sides exist but do not have the gull-wing forming, so are not connected to the PCB.

I haven't verified that the later 1LM2 has the same pinout as the 1LF5, but it's reasonably likely that it does.

AFAIK, the single-chip versions (1LQ9, 1RR2, 2AF1) don't have the external bus active, except on the 15C. There should be a factory test mode that enables the bus, but it is not publicly known how to activate that.