NP-41 Emulator (may be)

[Chris Chung]

(01-25-2016 07:29 PM)rprosperi Wrote:  So, it sounds like the basics are there. In a nutshell, Diego's product is a Flash chip with some logic, that emulates up to 12 of the 4K ROM Pages. He has built an easy-to-use Windows utility to "install" various ROM images, thus allowing one to utilize all the old (and even recently released) ROMs. So accommodating this single "chip" opens-up access to all the application ROMs, with each user building his/her own combination, and not requiring any of the internal ROM/RAM space.

I would love to explore more on ROM module. And I am a newbie on the HP-41C. I acquire my knowledge on Eric's Nonpareil under Linux, and as you mentioned there is no support of ROM modules. So I never see how it works! I would imagine that once a module is "parked" into one of the 4 ports (is it 4?), additional functions / programs will show on the "CAT" list and be available for use.

I can see there are microcode instructions to check memory location availability and I assume the boot code will do that to determine / setup when ROM modules are present. Currently on NP41 these functions are blocked. And I would like to explore them.

Would you suggest a very basic ROM module where I can download the binary and play w/? This is the only way I could understand the mechanism better. I used to run gdb w/ nonpareil to understand certain mechanism.

(01-25-2016 08:00 PM)jch Wrote:  I was almost asking for this kind of extension, but after looking at the MCU specs, especially available RAM, I didn't dare.
Wasn't your first design based on MSP430FR family ? Much more, hum... FRAM.

The 14-segment version still is using a 128K flash FRAM. This chip causes about $15 in single units versus the G2955's $4.
The 14-segment version is difficult to build mainly because of the direct LCD driving.
The extended registers are represented in nibbles (half-bytes) so that I am using 7 bytes per register. And of course it is tight, so it is quite different to ask for more. However, depending on how the ROM modules works, I might be able to extend via parallel or serial flash memory.

(01-25-2016 08:00 PM)jch Wrote:  HP-IL ? even on serial port ?

Another topic for me to read. My understanding is that it is a PC interface. My current design has uart at up to 115200. With a USB-Serial cable, I can do binary transfer. The format though is still open. (I am just using intel ihex format to fill memory holes)

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(01-25-2016 08:00 PM)jch Wrote:  While I was looking at the MCU specs, I also read the speed vs voltage curves.
3.6V, something like a Lithium Thionyl Chloride battery ?
Though not a coin cell, but with optionnal connector, you could also extend runtime, and thickness too :-(.

Jean-Christophe.

Not sure about the battery you mentioned, will look it up. One option is to use the re-chargable LIR2032 which is 3.6V. The MCU can detect voltage and switch clock frequency on the fly. So this can be made into auto-detect / allow fast mode option.