The 8bits side of Sporniket

[sporniket]

I won't blame @rubber_jonnie for my own weaknesses, even if it would have appended nicely to a string of threads with some kind of pattern in their title...

Through a french forums mainly focused on 8-bits computers, I could obtain at a very fair price a Thomson MO5, the computer that all French kids around 1985~1990 were acquainted with at school thanks to the "Computer Science for All" initiative of the French Ministry of Education. The last time I used it, it was at my last year of middle school, at the computer club that was happening just after lunch time, typing small programs in basic. (Then I would do the same program on the Omikron basic given with my Atari STE at home :D )

2022-10-25--mo5-arrival.jpg

The MO/TO family of computer (MO for "Micro Ordinateur" -Micro Computer-, TO for "Télé Ordinateur" -TV Computer-, as it plugged to the TV thanks to a SCART plug) was powered by a Motorola 6809 at a whopping 1 MHz. It also had an "optic pen" that allowed to have a very endearing (at that time) "touch screen" experience, when the teacher selected a program that used that peripheral.

For now, my new computer will need a good cleaning...

[rubber_jonnie]

I won't blame @rubber_jonnie for my own weaknesses, even if it would have appended nicely to a string of threads with some kind of pattern in their title...

It's OK, I've got your back :)

Through a french forums mainly focused on 8-bits computers, I could obtain at a very fair price a Thomson MO5, the computer that all French kids around 1985~1990 were acquainted with at school thanks to the "Computer Science for All" initiative of the French Ministry of Education. The last time I used it, it was at my last year of middle school, at the computer club that was happening just after lunch time, typing small programs in basic. (Then I would do the same program on the Omikron basic given with my Atari STE at home :D )

2022-10-25--mo5-arrival.jpg

The MO/TO family of computer (MO for "Micro Ordinateur" -Micro Computer-, TO for "Télé Ordinateur" -TV Computer-, as it plugged to the TV thanks to a SCART plug) was powered by a Motorola 6809 at a whopping 1 MHz. It also had an "optic pen" that allowed to have a very endearing (at that time) "touch screen" experience, when the teacher selected a program that used that peripheral.

For now, my new computer will need a good cleaning...

Is the MO5 based on the same reference design used by the Dragon32 and Tandy CoCo that also used a 6809 CPU? If so some of the software might be compatible.

[sporniket]

I have no idea as I don't know the computers you mention, I can just say that there is a gate array to glue the CPU to the memory and peripheral, and then I have some documentation about the memory map. Also, the MOs are incompatible with the TOs (different memory maps, different encoding of the tapes), so software editors had to publish 2 version each time.

If it helps you to assess the closeness of the designs with the Dragon32 and Coco, here are some schematics :

to7-dsp.png

mo5v1-dsp.png

[stephen_usher]

Is the MO5 based on the same reference design used by the Dragon32 and Tandy CoCo that also used a 6809 CPU? If so some of the software might be compatible.

It looks like the machine has a tokenized BASIC, like the ZX Spectrum, so even if the hardware is close to that of the Motorola reference design it wouldn't be at all compatible with the Tandy Colour Computer or Dragon 32/64 due to the ROM differences.

[sporniket]

After a little bit of research, I believe that I found (in the wikipedia page on the Coco) that the "reference design" would be the one from the MC6883 datasheet ?

On the other hand, the Matra Alice seems to be a clone of the TRS-80 MC-10.

[sporniket]

Since I opened the MO5 to clean the case (at least the top part, as the bottom part has the video cable attached to it) and the silicon keyboard, I took pictures of the motherboard :

mo5-board-top.jpg

mo5-board-bottom.jpg

[sporniket]

Since last time, I learned that the motherboard is one of the early version. The bodge wires are meant to be able to use some extension cartridge.

Anyway, I had no power supply. That's ok because I wanted to experiment with USB Power Delivery. This unit needs around 17V originally provided by a power brick. A little set back, the USB charger that implement power delivery and have small power (15~20W) do not output more than 12V, I had to buy a 45W one (I planned to buy one, eventually, but it's 30~40€ instead of 10~15€). The cheap one is not lost, as I plan to experiment on my STe as well, 5V at 3A should be just enough.

Anyway, here are the picture, this experiment is a success ! There is a little micro power down at startup, that I attribute to the switching to 15V after the negotiation of the module with the USB charger. Since I need a power switch between the module and the computer, the time taken to plug and switch on will take enough time to not suffer from it.

2022-11-02--00-schema-et-montage.jpg

The USB-PD module I used is this one : https://fr.aliexpress.com/item/1005003336833794.html

2022-11-02--01-branche-et-allume.jpg

2022-11-02--02-alive.jpg

And since I could use it a little, here is the obligatory "hello" in basic and in french :)

2022-11-02--03-hello-world.jpg

[sporniket]

Last week I got a "multi-rom" kit through the french forum, that will allow to use a collection of ROMs all in a single cart. Neat. I ordered the "classic" one (some games, utilities, and programming language -including an assembler-).

The kit is well made.

There is a little printed assembly manual

2023-04-02--00-content-of-the-kit.jpg

The sockets are already attached to the PCB with 2 soldered pins each, this is a time saver

2023-04-02--01-ready-to-solder.jpg

I still have a steady hand and good enough eyes (with my glasses), so no problem to solder the CMS capacitors too.

2023-04-02--02-done-soldering.jpg

There are supplemental marks on the chips and their sockets to help put them with the correct orientation.

2023-04-02--03-almost-done.jpg

Et voilà !

2023-04-02--04-done.jpg

Ready to test

2023-04-02--05-all-set.jpg

The title screen

2023-04-02--06-title-screen.jpg

One of the game included

2023-04-02--07-play-time.jpg

[sporniket]

This weekend I started to convert into Kicad the schematic of the MO5. Compared to the ST/STe, there is less to do, I am surprised to have done more than half of the work in a few days. I expect to finish -or to be near the completion- next week-end. Of course after that, there will be a reconstruction of the PCB, I plan to switch between that and the ST during this summer and autumn.

UC-50-001--02-CPU.png

UC-50-001--03-Gate-array.png

UC-50-001--04-RAM.png

UC-50-001--05-PIA.png

UC-50-001--09-Power-circuit.png

As usual, there is a github repository : https://github.com/sporniket/kicad-conv ... on-mo5--v1

[sporniket]

This week I got myself 3 more mo5s. In fact I was looking for one version with the EFCIS gate array and other differences with the "v1" I got before, so that I can also remake this version under Kicad. I took a chance on the net for a set of 2 (either v1 or v2, there was no picture of the inside) and then someone on the French forum proposed me his computer. It turns out the 3 are v2 variants, and the 3 have problem to run (not a problem for my project)

2023-06-09--01-3-mo5-v2.jpg

So, I looked at the computer I got from the forum member, the symptom is uninitialized screen, and on a quick power cycle, got a blinking purple border too :

2023-06-09--02-stripes-1.jpg

2023-06-09--02-stripes-2.jpg

This problem is caused by a stuck CPU (MC6809) early in the startup process, so I did quick checks with the multimeter :

VCC, to check we have 5V

2023-06-09--04-check-cpu-vcc.jpg

The /reset signal, no problem.

2023-06-09--05-check-cpu-reset.jpg

The clocks signal Q and E, seems ok (square, 50% duty cycle)

2023-06-09--06-check-cpu-q.jpg

2023-06-09--07-check-cpu-e.jpg

The R/*W signal, seems ok.

2023-06-09--08-check-cpu-rw.jpg

A0, seems moving.

2023-06-09--09-check-cpu-a0.jpg

D0, stuck at 0V like 3/4 low bits. I thought I could infer something, but there is no pull-up on the busses (address nor data)

2023-06-09--09-check-cpu-d0.jpg

so next time I will install the oscilloscope to watch what happens.