NP-41 Emulator (may be)

[Chris Chung]

(01-29-2016 01:43 AM)rprosperi Wrote:  

(01-29-2016 01:21 AM)Chris Chung Wrote:  Bob, I am currently running the 41CV ROM that comes w/ nonpareil, there is also a 41CX ROM that I have not try yet. As I understand that it has RTC. I haven't install clock crystal on the NP41S (I will called this design NP41S to differentiate it w/ the 14 segment 128K FRAM unit) but plan to make that available and try the CX ROM.

The CX adds a RTC, but also a bunch of general-purpose advanced programming commands, plus access to Expanded Memory (a simple offline file system, where you can store programs, create/store text files, save blocks of registers, etc. - but the extra storage space could be an issue). The CX RTC also includes setting multiple alarms which can simply beep or launch programs, auto-repeat on regular cycles, etc.

No idea if any of these features meet your goals, but thought I'd give you a thumbnail view of what the CX adds.

Eric's code supports the CX and I can run it under Linux, I haven't explored the advance functions and I can see there are additional bank switching activity when running that. Flash space I still have spare but RAM is really tight. The G2955 has 4K ram, for the 320/319 registers + the internal ones takes almost 3K and I am left only 1K to run the simulator, stack, etc.

(01-29-2016 09:11 AM)J-F Garnier Wrote:  

(01-29-2016 01:43 AM)rprosperi Wrote:  The CX adds a RTC, but also a bunch of general-purpose advanced programming commands, plus access to Expanded Memory.... The CX RTC also includes setting multiple alarms which can simply beep or launch programs, auto-repeat on regular cycles, etc.

Chris, the 41CX ROM has 3 pages more than the CV, and uses bank-switching.
So it depends if you have enough page space available to hold this version.
If, as you mentioned, you only have two free pages, you may start with use the CV ROM and include the Extended Function ROM and Time ROM, even if there is no accurate crystal-based 32kHz clock yet. These are the two most important extension ROM, and it will be approximatively equivalent to the CX.

J-F, the CX ROM is not a priority and it is something I can try later. As I am re-doing the PCB, I want to incorporate as much in the hardware design so that I don't have to re-do it again when I want to try something. The additions may or may not be used in future firmware but it is good to have them available for experiments.

With comments from Jean, I research current SPI flash chips and found that some manufacturers uses up to 4 pins for reads, so that it only requires 2 clocks to read a byte. This opens up the possibility of executing ROMs on the fly. So I am planting an 8 pin SPI flash on the next PCB to play w/ it.

The next PCB design is not yet finish and it can accommodate
. UART (need external USB-Serial cable).
. programming interface, TI Spy-Bi-Wire (i.e. simple Jtag)
. 2 levels (2 GPIO pins) of LCD backlight brightness.
. piezo buzzer.
. micro SD card.
. SPI flash.
. 2 x 8 pin socket that draws out the SPI pins and some others.