M5 Multi II - New version of Sord M5 multicart

[sirmorris]

How many years has it been? Too many. Anyhow, I've finally done what I should have done years ago and re-designed the cart.

The original was hard to build and overly complex. The new version has simplified the construction and the user experience. Game selection is by menu, no DIP switches or button presses    Just switch on, press a key and you're away.

Carts come with all the currently available (working) ROM images as well as BASICs -I and -G, which benefit from an additional 32K of RAM.

Carts are lovingly hand built to order. Price is £40. UK postage £3 1st class signed for. I'll ship anywhere, but I insist on tracked/signed for service when sending overseas.

Facebook usually gets the first pictures over at the Sord Computers group.

PM me for further details!

Charlie

[AndyRCM]

I will PM you mate. Nice work.

Andy

[sirmorris]

How are you getting on with your cart Andy?

[AndyRCM]

I have to admit we haven't even tried it yet - sorry. That is about to change though as hopefully we can get to our storeroom a little easier.
I will let you have feedback asap. Thanks mate.

Andy

[cdoty]

I just picked up one of these and I'm now looking for a way to use it to test software.

Obviously, the ROM image can be patched with another ROM, but I would suspect that the ROM socket has a limited number of insertion and removals before it would give out.

The next obvious choice would be to take advantage of the 32k to somehow load a program into memory. My coding is being done in assembly and not basic.
If I understand correctly the Sord M5 can load either basic or binaries from the cassette on power up. If so, can this take advantage of the extra RAM. And, are there any documents available on how to do this?

The final choice would be a ROM that allows files to be transferred through a serial style link to a PC. This is done on the Tatung Einstein computers, but it has plenty of extra memory and an actual serial connection.
Is the 32k enabled at all times? And, is there a connection that could work for serial communications?

[sirmorris]

The RAM on the cart is mapped to the upper 32k and is always present. It is contiguous with the built-in 4k, which appears at 0x7000-0x7fff.

The M5 has a printer port but it's output only. Probably the best way to get code into the machine would be to rig something up to one or both of the joystick ports. They're easy to read and if you were clever you could read multiple bits at once to increase the speed. Arduino or similar on one side, some nifty machine code on the other. In fact you could read a byte at a time, with 4 bits on UDL & R on both ports and a clock on one of the fire buttons...

All you'd need is a 6 pin mini-din lead and an arduino, some basic soldering chops.

[cdoty]

It turns out the easiest way was to encode the data into a CAS file.

It took me about 4 hours to figure out the cassette format and 30 minutes to write a utility to do it.
The manual documents the tape format pretty well, a few things were lost in translation.

MaxDuino recognized the CAS format, or at least thought it did. But, it would not load on the Sord M5.
I suspect it's a volume issue, as the phone has to be cranked up to max volume to work.

MAME castool was able to convert the CAS file to WAVE and it played fine through a phone.

[sirmorris]

Yeah that'll work too 

What are you working on?

[cdoty]

I have the start of a TMS-9918 based game, that runs on 11 systems, and I've tested on 8 of the 9 actual systems I have.