CP/M-65 for the KIM-1/PAL-1

[Eduardo Casino]

Hi,

I've made a port of David Given's CP/M-65 for the KIM-1 which uses Ryan E. Roth's sdcard6502 for the PAL-1(https://github.com/ryaneroth/sdcard6502), which in turn is based on George Foot's sdcard6502 for Ben Eater's 6502 computer (https://github.com/gfoot/sdcard6502).

It should also work with the PAL-1 with the following requirements:

- A PAL-1 with at least the 32K RAM and second 6532 expansion boards. The BIOS expects this memory to be present and checks is there is additional RAM above 0xA000

- An SDHC card of any capacity (only 32MB are used) and a generic Arduino SD card adapter **with 5V to 3.3V conversion**. See the links above for detailed requisites and connection instructions.

More RAM would be advisable, but I don't know if the PAL-1 ROM can be replaced with RAM.

Source code and binary distribution at https://github.com/eduardocasino/cpm65/tree/kim-1

To use it, download the `kim-1-sdcard` release, unzip it,  transfer the `diskimage.raw` file to the SD card using `dd`. Balena Etcher also works in Windows, just ignore the "not a bootable image" warning. Start the PAL-1 in TTY mode, load the `bootsd.pap` loader program into 0x0200 and execute it:

Cheers,

Eduardo

[Greg Holdren]

Very nice! I'll try it out on my Briel Micro-KIM.

Greg

[Neil Andretti]

Wonderful,

and yes, the PAL-1 can be expanded to 48 KB RAM with a 2nd modded RAM Card: https://netzherpes.de/post/more-ram-for-the-pal-1

I'll get the SD Card reader asap...

( for all germans: https://www.pollin.de/p/sd-speicherkartenmodul-810359 should work )

Nils

[Eduardo Casino]

The issue is that, even with 48K, it is not always enough. For example, I haven't be able to self compile the Pascal compiler unless the RAM goes up to 56K

Anyway, I think that even 32K is enough for a lot of fun stuff :)

@Greg, I did not mention it here because the PAL has it by default, but you also need RAM in the 0x0400-0x1400 range.

[GN Liu]

I feel it's time for some new expansions

[Ryan Roth]

Well done. I have tried porting this myself in the past, to no avail.

[Eduardo Casino]

The bootloader can be easily ROMable. It is a little less than 512 bytes, what would be a good location that does not trash any of the more typical expansions? 0xFE00, I guess?

[Neil Andretti]

AFAIK Exxx to FFFF cannot be decoded. so 0xDE00 would be the correct place.....

[Eduardo Casino]

Ah, OK, then I think it is not worth it. because I'd rather have the extra RAM. In any case, I'm doing it for the KIM-1 and I'll make the address configurable.

[Ryan Roth]

I can confirm this is working on my fully expanded PAL-1. Edurado, what SD card adapter are you using on your KIM-1?

[Eduardo Casino]

Great, thanks for the confirmation!

I'm using this cheap one:

https://www.amazon.es/dp/B0CQXNZH8T?psc=1&ref=ppx_yo2ov_dt_b_product_details

Even cheaper on Aliexpress, but those had next day delivery.

[Ryan Roth]

OK, and you just wired it directly to your KIM-1. I have a handful of these around, I'll have to try it.

Thanks

[Hans Otten]

There is some room in the KIM ROM at 1A96 to 1BFA, now filled with 0's.  Can be used with the KIM clones! 
Less than 512 bytes though ...

[Eduardo Casino]

The size of the boot prom for the sdcard version is exactly 487 bytes. I haven't really tried to optimize it for size, but 356 bytes sound very challenging :)

[Hans Otten]

I also feared it was too little,  seeing your code, not much room for improvement. Lets keep wozmon in it!

[Eduardo Casino]

Well, still have to test it because I'm away for a few days, but I think I've been able to squeeze it into 354 bytes :) 

[Greg Holdren]

Eduardo,

Thanks for the info. I will try out in the next few weeks and report back on the progress.

Greg

[Eduardo Casino]

After a bit of tweaking, I have reduced it to just 345 bytes, because my KIM-1 ROM is modified to add the 'X' command, which launches the xKIM monitor, and I only have 346 bytes left.

There are now three bootloader files in the distribution:

* bootsd.bin, which is the binary meant to be loaded at 0x200

* bootsd.pap, same file in PAP format

* bootsd-kimrom.bin, which is the romable version and has to be placed at 0x1AA0 (or 0x2A0 relative to the KIM-1 rom)

The romable version has two entry points:

* 0x1AA0 is for cold start, that is, you can point the 6502 reset vector to 0x1AA0 if you want to start CP/M-65 at reset. In this case, the TTY is initialized to 9600 bauds, so make sure that your terminal is configured to that speed.

* 0x1AB2 is for booting from the KIM monitor

If there is an error initialising or reading the SD card, a "00" or "01" will be displayed on the terminal, respectively, and the boot loader will give control to the KIM monitor.

You can download the new version from https://github.com/eduardocasino/cpm65/releases/download/0.2-sdcard/kim-1-sdcard.zip

[Hans Otten]

Awesome! 
CP/M-65 is a capable OS, with not too much tools and programs yet.
It is gaining more users since the ports to various systems.

One of these is the Olimex Neo6502,  a 65C02 system at > 5 MHz with a Raspberry Pi Pico for memory, video, USB keyboard, flash USB etc. 
I have both Neo6502 SBC as the Neo6502PC (a small computer with LCD screen). Fast as lightning!

Hans

[Eduardo Casino]

OK, this is the last one, I promise ;-D

New release for KIM-1 and PAL-1 with a 1541 drive.

Limitation: It only currently works for 1541 drives (or pi1541 with 1541 personality). Other drives or SDIEC are not supported.

There are images and boot loaders for the KIM-1 with the xkim1541 extensions installed at 0xF000 and for the PAL-1 with the same extensions at 0xDA00, as modified by @netzherpes.

* Burn the appropriate image into a floppy (or load it into the pi1541 SD card) NOTE: You must burn a binary image, just copying the CPM.PRG file wont work, because the CPM file system is in a hidden file.

* If you also have my modified xKIM monitor, then load the 'CPM' program and jump to address 0x6000

* If not, load the  bootiec-kim or  bootiec-pal bootloader into 0x200 and execute it

Note: It is really, really slow. I've done it just for fun and because it was trivial once I had David Given's C64 version and my xkim1541 extensions, but it is mostly useless. You can see your beard grow if you compile anything with the assembler.

Download from https://github.com/eduardocasino/cpm65/releases/tag/0.1-iec

Mandatory screenshot:

Eduardo

[Nils Andreas]

Wohooooo

I can copy it works on my PAL-1 with a real 1541  

Brilliant Job as always Eduardo!

🙏 

¡Gracias!

Von meinem iPhone gesendet

Am 26.07.2024 um 22:02 schrieb Eduardo Casino <eduardo...@gmail.com>:

OK, this is the last one, I promise ;-D

New release for KIM-1 and PAL-1 with a 1541 drive.

Limitation: It only currently works for 1541 drives (or pi1541 with 1541 personality). Other drives or SDIEC are not supported.

There are images and boot loaders for the KIM-1 with the xkim1541 extensions installed at 0xF000 and for the PAL-1 with the same extensions at 0xDA00, as modified by @netzherpes.

* Burn the appropriate image into a floppy (or load it into the pi1541 SD card) NOTE: You must burn a binary image, just copying the CPM.PRG file wont work, because the CPM file system is in a hidden file.

* If you also have my modified xKIM monitor, then load the 'CPM' program and jump to address 0x6000

* If not, load the  bootiec-kim or  bootiec-pal bootloader into 0x200 and execute it

Note: It is really, really slow. I've done it just for fun and because it was trivial once I had David Given's C64 version and my xkim1541 extensions, but it is mostly useless. You can see your beard grow if you compile anything with the assembler.

Download from https://github.com/eduardocasino/cpm65/releases/tag/0.1-iec

Mandatory screenshot:

<Captura de pantalla 2024-07-26 220009.png>

Eduardo

On Saturday, July 20, 2024 at 9:31:26 PM UTC+2 Eduardo Casino wrote:

After a bit of tweaking, I have reduced it to just 345 bytes, because my KIM-1 ROM is modified to add the 'X' command, which launches the xKIM monitor, and I only have 346 bytes left.

There are now three bootloader files in the distribution:

* bootsd.bin, which is the binary meant to be loaded at 0x200

* bootsd.pap, same file in PAP format

* bootsd-kimrom.bin, which is the romable version and has to be placed at 0x1AA0 (or 0x2A0 relative to the KIM-1 rom)

The romable version has two entry points:

* 0x1AA0 is for cold start, that is, you can point the 6502 reset vector to 0x1AA0 if you want to start CP/M-65 at reset. In this case, the TTY is initialized to 9600 bauds, so make sure that your terminal is configured to that speed.

* 0x1AB2 is for booting from the KIM monitor

If there is an error initialising or reading the SD card, a "00" or "01" will be displayed on the terminal, respectively, and the boot loader will give control to the KIM monitor.

You can download the new version from https://github.com/eduardocasino/cpm65/releases/download/0.2-sdcard/kim-1-sdcard.zip

On Tuesday, July 16, 2024 at 8:25:12 PM UTC+2 Eduardo Casino wrote:

Well, still have to test it because I'm away for a few days, but I think I've been able to squeeze it into 354 bytes :) 

On Tuesday, July 16, 2024 at 2:23:19 PM UTC+2 h.o...@hansotten.com wrote:

I also feared it was too little,  seeing your code, not much room for improvement. Lets keep wozmon in it!

On Tuesday, July 16, 2024 at 2:21:09 PM UTC+2 eduardo...@gmail.com wrote:

The size of the boot prom for the sdcard version is exactly 487 bytes. I haven't really tried to optimize it for size, but 356 bytes sound very challenging :)

On Tuesday, July 16, 2024 at 1:56:22 PM UTC+2 h.o...@hansotten.com wrote:

There is some room in the KIM ROM at 1A96 to 1BFA, now filled with 0's.  Can be used with the KIM clones! 
Less than 512 bytes though ...

 

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[Neil Andretti]

I finally got my SD card module today, so I am ready to test my 48 K ROM setup with CPM65 on the PAL1.

While on the research about CPM65 I came to an interesting project called SORBUS, a minimalistic 6502 system consistion only of an 65C02 and a pico Pi.

The project by "svolli"  seems easy enough for my soldering skills :D Svolli provided all gerber files needed to order all PCBs.

https://xayax.net/sorbus/

I think this will be my next project \o/

Nils

[Neil Andretti]

SD Module wired, result is

"Abnormal termination. Error Code: 00"

I will try another SD card the next days. Right now it's a 8GB micro SDHC from sandisk

Without an SD card inserted, the program just hangs.... so it seems to be an issue with the SD card.

[Eduardo Casino]

Hi Nils,

Code 00 means initialization error. If you were able to write the image from your PC, then I would double-check the wiring.

Can you please share which module are you using and how is it wired?

Eduardo

[Neil Andretti]

I wrote the image with Balena Etcher, will also try dd later.

The sd module is the cheap Pollin one with volatage regulator onboard.

[Eduardo Casino]

I can't be 100% sure from the picture, but the wiring seems OK to me:

MISO -> PA1

MOSI -> PA2
SCK -> PA3

CS -> PA4

I think the problem may be in the adapter. Although it has a voltage regulator to provide 3.3V to the SD, it doesn't have a lever shifter for the I/O pins, so the 6530 is frying the SD card data and clock lines with 5V!

This is the one I'm using:

https://www.amazon.de/dp/B0CQXNZH8T

They can be found cheaper on Aliexpress.

[Eduardo Casino]

Just FYI, David Given has already merged my KIM-1 ports into the main branch in his repository: https://github.com/davidgiven/cpm65

[Neil Andretti]

Soooo. finally with a new adapter and a new sd card my setup is working.

hooray \o/

I can max the freem mem from 3000-E000  (I guess from 2000-3000 is the OS located).

Thanks Eduardo for helping getting this stuff running. I wonder how many programs will be ported to CPM65

More l8r!

Nils

[GN Liu]

Congratulations Nils!!

I have always had a dream of writing a UNIX-like operating system for the KIM-1, and that dream still exists.

[Neil Andretti]

Hey Liu, 

the most promising OS is surely GeckOS... I wonder if we can bribe Andre Fachat somehow to assist :D

https://de.wikipedia.org/wiki/GeckOS

[GN Liu]

OMG, this is far away advanced than my dream ~~~

[Ryan Roth]

Where does the CP/M-65 for the KIM-1 banner come from, the boot loader, or the image on the SD card? I'm trying to debug why it just exits on my KIM-1 reproduction. Thanks.

0200 D8 G

CP/M-65 for the KIM-1

KIM
EDF1 1E 

[Eduardo Casino]

It comes from the image on the SD card, from the BIOS, to be exact.

What is your memory configuration?

[Ryan Roth]

I have 2000-FFFF all set to RAM on my RAM/ROM board. What I am trying to do is hack in a SD card reader, so I was mostly curious if the KIM-1 was reading from it or not. Don't laugh :)

[Eduardo Casino]

0400-13FF must be also present. The disk buffer is at 0200-03FF and the the BIOS relocates itself from 0400.

Love the Frankencard! :-D

[Ryan Roth]

Thanks, I figured it worked for a good prototype. I turned on 0400-13FF, but I still see the same behavior. The memory in this area passes the glitchworks memory test.

[Eduardo Casino]

I've just tested with (I think) your exact setup and I can't reproduce the problem. The BIOS occupies just a few sectors at the beginning of the SD card. It could be that the image is not completely transferred to the SD card or that the card is faulty.

[Ryan Roth]

I'll make another franken-adapter as this SD card works in my PAL-1 using another one of these adapter