Programmable RAM/ROM/Video/FDC card for the PAL-2

[Eduardo Casino]

Hi folks,

I've completed a PAL-2 version of my PicoW-based card. It has some nice features and others will be added via firmware updates:

• Can emulate RAM and/or ROM at any address of the PAL-2 memory map and with byte granularity so you can individually enable, disable, mark as RW or RO each and every byte of the 64K address space. It can also take over the PAL-2 system RAM and ROM, so it can be used as a diagnostic tool.
• A default memory map and data are stored in the Pico flash memory and it is available at boot time.
• Runs a configuration web server with a RESTish API so you can configure and read or write all or any part of memory contents over Wifi and on the fly.
• The board is powered by the PAL-2, but it can also be dual powered by the PAL and the USB port. This is useful, for example, if you are developing a boot ROM: you can power off the PAL, modify the boot program over wifi and turn it on again to test your changes.
• It emulates an MTU K-1008 Visable Memory Card. It can be mapped to the same addresses as the real one (and change that mapping while running) and gives configurable composite NTSC or PAL output through the RCA connector. VGA output is planned but unimplemented at the moment.
• Emulates an K-1013 floppy disk controller with up to four disks, reading and writing to disk images into the SD card. Tested with CP/M-65 (https://github.com/davidgiven/cpm65#kim-1-with-k-1013-fdc-notes) and work-in-progress, reverse engineered CODOS v1 (https://github.com/eduardocasino/mtu-misc)

A config utility, memcfg, is provided to setup the board and facilitate the communication with the REST API. This is an overview of its functionality. Please see the README file (https://github.com/eduardocasino/kim-1-programmable-memory-card/tree/main/tools) for detailed usage instructions:

• Generate configuration files ready to be flashed into the Pico: WiFi parameters, video format and default memory map and contents.
• Get or modify the memory map.
• Read memory contents and generate output in different formats: hexdump, Intel hex, binary, prg and raw. The raw format is how the Pico stores the memory map. Each memory address contains a 16 bit integer. The least significant byte is the content and the most significant one is a bitmap that indicates if the memory is enabled or disabled and writeable or read-only.
• Write memory contents from file or command line. The file formats supported are Intel hex, binary, prg and raw. Also, binary and raw data can be specified as a string from the command line.
• Modify the base address for the K-1008 emulation

Everything is available at my GitHub repository: https://github.com/eduardocasino/kim-1-programmable-memory-card/

IMPORTANT NOTE

The PAL-2 behaves differently from the KIM-1 when the #DECEN signal goes high.

On the KIM-1, this signal disables all internal address decoding, allowing an expansion card to take over. However, on the PAL-2, the signal is wire-ORed with the 8K0 enable output of the first decoder, so it effectively has no impact.

To enable expansion card functionality, a simple modification must be performed on the PAL-2:

• Cut the trace that connects pin K of the Application connector to pin 12 of U6, and the trace connecting pin 12 of U8 to ground.
• Solder a wire from pin K of the Application connector to pin 12 of U8.
• Solder a 3.9kΩ resistor from pin 12 of U8 to any ground point on the board.

See the details here: https://github.com/eduardocasino/kim-1-programmable-memory-card/tree/main/hardware/pal-2

Cheers,

Eduardo

[Hans Otten]

Thank you Eduardo!

This may boost interest in the fabulous PAL-2.

Easy to build since it is all through hole and available components. 

If you want to learn about the Micro Technology Unlimited (MTU) cards that are emulated, the K-1013 and K-1008 are well documented on my (recently renewed)  MTU pages at Micro Technology Unlimited – Retro Computing

There are long! threads on forum64.de (in English) about the replica K-1013 and replcia K-1008 and the KIM-1 replica  and CODOS reverse engineering by Eduardo

K-1013 Floppy Disk Controller replica - Sonstige Commodore - Forum64

K-1008 Visable Memory card replica (WIP) - Sonstige Commodore - Forum64

MTU CODOS for the KIM-1 and MTU-130 - Raritäten & Seltenes - Forum64

Instandsetzung und Nachbau eines Kim-1 - Sonstige Commodore - Forum64

Any interest in building this card? Is there a demand for kits?

Hans

[Neil Andretti]

This is absolutely amazing! 

Liu, could you produce it and sell Kits? This would make things a lit easier for us ;)

[John Kennedy]

A kit would definitely be nice.

[GN Liu]

Thanks Eduardo for making such a great kit, I think this is a must have expansion!

Nils,

Eduardo gave me permission to produce this kit, and I’ll be adding it to my store ASAP.

Liu

[Eduardo Casino]

I've upgraded the firmware and the memcfg tool. It is now possible to perform the following operations over WiFi:

• Transfer files between your PC and the SD card, as well as list, copy, rename, and delete files on the SD card (via the new "file" command).
• Mount and unmount images, and save the current mount map as the default for booting (via the new "mount" command).

Cheers,

Eduardo

[Luciano Veronese]

Hello Eduardo and thanks for this great addon. I am assembling your KIM-1 replica. It's not clear to me if this awesome board is just for PAL-2 or it works also with your KIM-1
Thanks
Luciano

[Eduardo Casino]

Hi Luciano,

Thre is a KIM-1 version, but it is SMD, so it is a bit more complicated to build, specially if you don't have experience with surface mounted soldering. It is in the same repository.

You'll also need an MTU backplane, either this simple, passive, one: https://github.com/eduardocasino/kim-1-mtu-expansion-card
or this buffered one: https://github.com/eduardocasino/kim-1-mtu-motherboard

The simpler one works perfectly well and it is the better option if you already have (or plan to build or buy) a Corsham's style IO card like this one: https://retro-spy.com/product/kim-1-i-o-board/  (Disclaimer: I'm not affiliated in any way)

The buffered one is a complete solution. You can choose between thre daughter boards: one with an RS-232 connector for the terminal, another with USB-C or a third one with WiFi (the last two also have some SMD components) You have the details on the Github repo.
 
Ciao,
Eduardo

[Hans Otten]

Since the PAL-2 is in essence a KIM-1 with application and expansion connectors, with the DECODE ENABLE hardware patch applied, it may be possible to design a connector between KIM-1 22-pin edge connector and the PAL-2 connector on this card? This would make this easy to build board accessible to the KIM-1 (replica, there are many now)  owners.

[Eduardo Casino]

Yes, sure, that would be a simple 1 to 1 connector. I may also design a through-hole version for the KIM-1.

[Eduardo Casino]

Any thoughts before sending the board to fabrication?

[GN Liu]

Simple and beautiful in my eyes.

[Adolfo Fernandez]

Yes, beautiful

[Hans Otten]

awesome! this way only one board is necessary for PAL 2 and KIM-1.

KIM-1 users can add this simple connector. 
And any other PAL 2 extensions to appear can be used on a KIM-1 this way. 

[Eduardo Casino]

I'm having a hard time finding a 2×22 right-angle female connector for the adapter. On the usual low-cost platforms, they only offer 2×20 to 2×24, and on specialized sites, it's either unavailable or requires a minimum order of 500 units. Any leads?

Thanks,

Eduardo

[Eduardo Casino]

Sorry, it was a case of late-night blindness. Found it at least on DigiKey, probably available elsewhere too.

[GN Liu]

I can put them on shelf in August.

Best,

Liu

[Hans Otten]

Yea, sometimes hard to find. In emergencies you can take for example a 40 pin and saw off the unwanted part. and file off the rough end. 

[Eduardo Casino]

Thanks, Liu. I’ll probably go with Hans’ sawed 40x2 trick for testing, but it’s nice to have options for sourcing the BOM.

[GN Liu]

It’s currently my children’s summer vacation, so my schedule isn’t very consistent.

 
I will prepare and put this cool expansion and its related components (daughter boards) on the shelf this month.

[Eduardo Casino]

Great news, thanks!

[Hans Otten]

Indeed, great news!

[Eduardo Casino]

I've finished the KIM-1 adapter for the PAL-2 version and it works great :)

Everything at my GitHub repo: https://github.com/eduardocasino/kim-1-programmable-memory-card/tree/main/hardware/pal-2-kim-adapter

Now working on the firmware to finally enable the VGA output.

Cheers,

Eduardo

[GN Liu]

Thanks Eduardo! 

Now all parts are ready, I'll put them into production.

Best,

Liu

[Neil Andretti]

Waiting is so boring .... aaargh....

[GN Liu]

It’s my fault — there’s been a big delay in my progress…
But it will resume this month. Please give me a few more weeks for the cool expansion!

SOOOOOOOOOOOOOOOOOOOORRRRRRRRRRRRRRRRRRRRRRy......

[Eduardo Casino]

Hi all,

After a long while, I've finally added VGA output to the firmware. Two modes are supported: 640×400@70Hz and 640×480@60Hz (with horizontal bars).

Please note that the coax and VGA connectors share the HSYNC and VIDEO signals, so make sure to configure the correct output before connecting a monitor!

The code is in the vga branch of my repo:
https://github.com/eduardocasino/kim-1-programmable-memory-card/tree/vga

And here's the mandatory photo. My VGA monitor is a bit old and doesn’t support the 4:3 aspect ratio, YMMV. The card in the picture is the MTU version, but the same firmware works for the PAL-2/KIM-1 one too:

[Hans Otten]

The finishing touch! These cards packs so much functionality for KIM-1 and PAL-2!
A 198x system dream come true: so much RAM and ROM, a graphic display, a full blown seral interface (with e.g Teraterm ), floppy drives and with a choice of operating systems.

[Lars]

Are there any other OS‘s, beside CPM-65, which can be used with this „swiss-army-knife“ board?

[Eduardo Casino]

Hi Lars,

You can use the rebuilt CODOS V1, which was the OS MTU originally designed specifically for the K-1013.

It’s not as handy as CP/M-65 yet, since for now the only available programming language is MS Basic. It’s more of a paleological project than anything else, and still a work in progress and currently on hold due to other priorities. My plan, when time permits, is to add graphics support for the K-1008 and at least a native assembler.

Everything’s in the link below. See the build instructions to generate a KIM-1 version. Also, check out the IMU.C utility. It makes it super easy to manage disk images on the SD card. Just do TYPE IMU.T for instructions.

https://github.com/eduardocasino/mtu-misc

As for CODOS V1 documentation, Han's site comes to the rescue:

http://retro.hansotten.nl/6502-sbc/mtu/mtu-codos

However, keep in mind that the memory map isn’t the same as the original, and I haven’t documented it yet. You’ll need to place the boot ROM at FF00 and jump there to launch CODOS from the disk image.

Eduardo.

[Lars]

Hi all,

I got PCBs and Parts this week and put everything together today.

Compiling the Code from the VGA branch was really easy using the Eduardos documentation from github.

So far I get Pixels shown on my TV using composite. If I use my Hauppauge Capture card the picture is slightly nervous.
I will test VGA as well but I have to look for a cable.

I tried to configure the Card for CPM-65 but I can get it to work.

I have formatted the SD Card with exFat and I can see the mounted CPM Image file using memcfg.

• ./memcfg mount 192.168.0.144
• 0: -> cpm65.imd
• 1:
• 2:
• 3:

But when I try to start CPM-65 using the loaded bin or pap (0x0200) boot file nothing happens.

Do I miss something like a rom for the emulated fdc controller?

I attach my two yaml config files, maybe I configurred something wrong?!
I haven't changed anything at the PAL-2 switches.

Anyway, this card is great, a must have from my point of view. The PAL-2 Version is also very easy to assemble.
Just add the documented DECEN mod to the board, connect the DECEN cable, done.

Many Thanks Eduardo!

[Eduardo Casino]

Hi Lars,

Looks great in purple ;)

I see a couple of problems with your configuration:

fdc:                                 # K-1013 FDC emulation

 enabled: true                       # Wether if the FDC emulation is enabled or not

 usrram: 0x4000                      # Address of the User DMA RAM block

 sysram: 0x8000                      # Address of the System DMA RAM block

 optswitch: false                    # Optional: Enable/disable the card "options" switch.

CP/M-65 expects usrram at 0xC000 and sysram at 0xe000

---

start: 0x2000

end: 0xdfff

enabled: true

type: ram

Start is OK, end should be 0xffff. When you enable the FDC controller, the Pico card needs to control all the controller's memory map.

The boot prom is not needed but, if you enable it, then the config should look like this:

---

start: 0xff00

end: 0xffff

enabled: true

file: "kim1cpm65.bin"

type: rom

---

start: 0xffe8

end: 0xffe8

enabled: true

type: ram

---

start: 0xffea

end: 0xffea

enabled: true

type: ram

---

start: 0xffef

end: 0xffef

enabled: true

type: ram

---

start: 0xfffa

enabled: true

type: rom

data: "\x1c\x1c\x22\x1c\x1f\x1c"

Those RAM addresses are the K-1013 registers and need to be writable.

Cheers,

Eduardo

[Lars]

Thanks Eduardo!

I changed the usr and sysram locations, modified the memmap as written above.

Voila, CPM boots within seconds.

[Lars]

I am experimenting with the memcfg write command to upload bin data files to let my Zenith Amber Monitor show some pics which i have found at Forum64.

It works really well. 

But I losing the network connection after a while and get "Error executing the request: Couldn't connect to server" or "Error executing the request: Server returned nothing (no headers, no data)" back. 

The connection Led is still on.

I tried the master and the vga firmware. Both have the same behavior.

Any Idea what can cause this.

The interface is not pingable, correct?

[Eduardo Casino]

Hi Lars,

Connect the Pico to your PC via USB before powering up the PAL. Open a terminal emulator and connect to the PICO, reset the PICO and wait for the led to stop blinking. You should see some debug messages with the connection. Power up the PAL and use it normally. When you loose the connection, tell me what the debug messages say.

The Pico W antenna is not particularly sensitive. Do you have good WiFi coverage?

Dumb question: you are using the tools from the corresponding firmware version, right?

Cheers,

Eduardo

[Lars]

:: Dumb question: you are using the tools from the corresponding firmware version, right?

Yes.

:: The Pico W antenna is not particularly sensitive. Do you have good WiFi coverage?

I think so, my AccessPoint is about 2,5m away. But I will try other positions.

Does this help?

[Eduardo Casino]

Sorry if this message is duplicated, it seems that it was rejected.

Yes, it helps, thank you.

Could be a wifi problem, which does not seem likely if you are so close to the router, or maybe I introduced a bug in the web server in one of the recent updates, although I have not experienced those problems, AFAIK.

After the problems begin, does any retry succeed or do you have to reset the Pico?

I won't be able to make some tests until later this week, but I'll get back to you as soon as I can.

Eduardo.

[Lars]

No need to hurry!

What I am doing is playing around for a better understanding what is possible with the PAL-2 and your board.

So far I have to reset the board every time to get the network connection back.

All my tests are done from WSL, I will test with Linux in the next days ad well.

Many Thx

[Eduardo Casino]

I'm using WSL as well, so that is not the problem for sure.

Eduardo.

[Eduardo Casino]

Just another question: Are you experiencing those problems when using the composite video output, the VGA one or both?

Thanks.

[Lars]

I have only tested the Composite Video Output until now.

[John Kennedy]

Anyone in the US interested in sharing the cost of the PCBs?

[Eduardo Casino]

Hi Lars,

I've been executing "memcfg config" in a loop trying to reproduce the issue, and it is over 1000 successful repetitions and counting. No glitches so far.

I'll do a more complex test tonight (including mounting, unmounting, sending files back and forth, changing memory maps and so on) to stress it a bit.

Anyway, could you please re-flash the firmware from the VGA branch and rebuild and flash the setup file, just to make sure there are no mismatches.

Eduardo.

On Monday, December 1, 2025 at 3:58:52 AM UTC+1 Lars wrote:

[Lars]

::could you please re-flash the firmware from the

::VGA branch and rebuild and flash the setup

::file, just to make sure there are no mismatches.

Will do. Thanks for testing.

[Lars]

Hi,
I have two wireless Networks. One is Router based and one using a dedicated AccessPoint from Ubiquiti.

Both Wireless Networks provide WPA2/WPA3 mixed 2.4/5GHz networks.

As I did my previous tests with the (normally) much better Access Point based Wireless Network, I tried now the test with the Router based Wireless which is also only 2m away from the Pico.

It looks like this time the test works much better.

I run a loop of the "memcfg config [IP]" command with a two second delay for >670 times without response problems (still counting).

I have not re-flashed the firmware, I have just rebuild the setup with the other wireless network.

Perhaps the position and orientation of the wireless antennas make the difference, even though both are only 2m away from the Pico.  

@Eduardo could you please share your test script here if you built one.

Many Thx

Lars

[Eduardo Casino]

> @Eduardo could you please share your test script here if you built one.

Not yet, I'm just running a bash loop. The script is my plan for tonight, unless I fall asleep ;)

Another possible cause is insufficient power, which would explain why you have to reset. Make sure you power the PAL-II with an adapter rated at 2A or more.

Eduardo