Lab-Volt 6502 Trainer - Looking for instructions

[groinksan]

Just as the subject suggests... I received a Lab-Volt 6502 Trainer. I'm familiar with the workings of the 6502. However, this trainer isn't exactly intuitive. I'm looking for something like a quick get-started sheet of some kind, so I can start playing around with the unit. My intent is to demonstrate the trainer at the Mini Maker Faire in my area. I already ordered the accompanying book via Amazon, but it is going to take awhile to get to my front door.

Thanks!

[Dr Jefyll]

Welcome, groinksan. Do you have any photos you can share with us? (They can be included as an attachment with your post -- no need to use a third-party host.) Please also share any links you may've found.

Have you powered up the unit? Does it even have a power supply? Or is that something you'll be required to provide?

cheers,
Jeff

[groinksan]

The unit runs great. I had to purchase banana plugs, and modify a 5vDC wall wart with those plugs to get the unit powered (req's 700mA, or more if you have the additional modules.)

The trainer has a 4x4 keyboard. You use it to enter hex, but it also has pre-programmed functions. FWD and BACK upon power up scrolls through memory. If you set the unit to STEP mode, the STEP button will execute code one at at time. Otherwise, I believe with the unit in RUN mode, it'll plow through the code just like any computer. I believe GO will allow you to enter the start address.

As for the layout of the trainer, and so far this is from what I can see on the memory decoder, ROM resides in F000. RAM resides in D000. And, I think the "USER ROM" is in E000.

It also uses the 6520 PIA to output to the display. The display is just six 7-seg display parts, with four for the address bus, and two for the data bus. There are two 20x2 headers, so you can use those to tap into and allow for peripherals, such as a printer or serial interface, or even more RAM. There are other things like an I/O decoder, output data latch, and some LEDs you can blink off/on, but I've yet to figure out how to use those.

[BigEd]

Very nice find groinksan! And welcome.

It would be nice if you could dump the ROM - that will spill all the secrets of what this trainer is capable of.

It's just possible you can get something from the manufacturer, who seems to be Festo or Festo Didactic, who have a North American presence but might actually be from Germany. See
http://www.festo-didactic.com/ov3/media ... tems_1.pdf and also http://www.festo-didactic.com/de-de but I think you'd need to find a nice helpful person with access to materials from obsolete product lines.

It seems that the board was used educationally in Turkey... and in fact as you may know it seems to be allied to the Visual 6502 project of Nurettin Topaloğlu whose site features a photo of this board:
http://w3.gazi.edu.tr/~nurettin/visual_en.html
but, alas, with no further detail. (His Visual 6502 is a GUI simulator for Windows, not to be confused with the in-browser transistor-level simulator at visual6502.org)

Elsewhere, someone notes

Quote:

The native language of the software appears to be Turkish, but I found a language setting in an ini file (reversed the order of Turkish/English) and that switched it to English mode. I haven't messed with it too much but it does look pretty cool, and the reason I wanted it was because it has some "virtual" switches and LEDs to play with and supposedly interfaces with my trainer somehow

There's a book "Microprocessor Troubleshooting: Concepts and Applications" published by Buck Engineering Company which might cover this Lab Volt board. Or even better, one called "MICROPROCESSOR - CONCEPTS AND APPLICATIONS" by Buck Engineering
which features this board on the cover.
http://www.amazon.com/dp/B002K7TK8Y/

[groinksan]

I'll see about getting the monitor ROM dumped. I have a ROM reader, so I'll try to get working on that this week.

In the meantime, I've been studying the board. From what I can get out of the memory decoding portion, the memory map looks like this:

$0000 - $0003 - PIA (6520)
$0004 - $CFFF - not recognized by the immediate hardware
$D000 - $D7FF - RAM
$D800 - $DFFF - not recognized by the immediate hardware
$E000 - $EFFF - User ROM
$F000 - $FFFF - Monitor ROM

There are memory cards for this trainer. They're quite hard to find. So I presume those unused portions of memory space can be used by the memory card.

[GARTHWILSON]

groinksan wrote:

There are memory cards for this trainer. They're quite hard to find.

Fortunately now it is becoming economical to make your own. (You always could with wire-wrapped breadboards, but now you can get PCBs at prices that are affordable to hobbyists.)

[Dr Jefyll]

groinksan wrote:

From what I can get out of the memory decoding portion, the memory map looks like this:

Hmmm -- no RAM in Page 0 and Page 1? ($00xx and $01xx) Is that what you mean? It seems very unlikely, given that 6502 makes special use of those areas for indirect pointers and for stack. I suspect there's a either misunderstanding or a faulty conclusion.

Quote:

There are memory cards for this trainer. They're quite hard to find.

Are they worth finding? Memory technology has advanced drastically, and IMO there's not much value in locating one of the original memory cards intended for this trainer. For example the original might be crammed full of memory IC's but only yield, say, 8 KBytes. Nowadays you can economically build your own memory expansion (wire-wrap or PCB, as Garth suggests) of any desired capacity (up to 64K) using just a single memory IC.

-- Jeff

[barrym95838]

Dr Jefyll wrote:

... Nowadays you can economically build your own memory expansion (wire-wrap or PCB, as Garth suggests) of any desired capacity (up to 64K) using just a single memory IC.

-- Jeff

Yeah, but they don't smell the same!

Mike B.

[groinksan]

Dr Jefyll wrote:

groinksan wrote:

From what I can get out of the memory decoding portion, the memory map looks like this:

Hmmm -- no RAM in Page 0 and Page 1? ($00xx and $01xx) Is that what you mean? It seems very unlikely, given that 6502 makes special use of those areas for indirect pointers and for stack. I suspect there's a either misunderstanding or a faulty conclusion.

I see your point. The board uses a 74LS156 and 74LS12 for memory decoding, but monitors only A10, A12 and A13. When following A10, it is used to reference the only two RAM modules on the board, both of which are hard coded at $D0-D3 and $D4-D7 (uses 2114L2 modules.) If A12 is H, and A13 is L, then the 74LS12 kicks in, and RAMCS is set, which is only connected to the two 2114L2 modules. I can't see any other RAM module which could possibly tie into page zero and one. I posted hi-res photos of the board in my earlier posts, so maybe you can catch something on it that I'm missing.

[BigEd]

If the memory decoding doesn't use A14 or A15, then everything will get mirrored 4 times on 16k boundaries. But that still doesn't place any RAM over page 0 and 1. Have you perhaps missed an inversion of an address bit?

$0000 is also $4000, $8000 and $C000
$1000 is also $5000, $9000 and $D000
$2000 is also $6000, $A000 and $E000
$3000 is also $7000, $B000 and $F000

(Hope I got that right...)

[groinksan]

I found this schematic of the board. The resolution is low, so reading it is difficult.

[barrym95838]

Perhaps a misunderstanding of the silk-screen labeling on the top of the board? It says "RAM (D0-D3)" and "RAM (D4-D7)", but my instincts take that to mean that each RAM is four bits wide ... I'm not a hardware guy, so I could be spouting nonsense.

Mike B.

[Martin A]

The 2114 is 1k x 4 bits, and that schematic does appear to show D0-D3 to one chip and D4 to D7 to the other.

The Eprom in the photo looks like a 2k 2516, although the schematic appears to show an option for A11 to be connected for a 4k eprom . The user rom appears to be wired for 4k as well.

So maybe its Ram 0000-03FF with lots of shadows up to 1FFF, User rom 2000-2FFF, monitor rom 3000 - 3FFF then that's repeated 4 times so that there is a monitor rom shadow covering the vectors ?

[BigEd]

Hi groinksan are you still investigating this trainer? Do you have the means for dumping and sharing the ROM contents? If not, we can surely write a little program which will output an audio or radio signal carrying the ROM contents, and then decode the result back to binary for investigation. (We can get the output on the address pins, so no need to figure out how to drive the I/O)

(Ref. my puzzle thread, and also this blog post recently mentioned on hackaday.)

[groinksan]

I just yesterday received the instructional book. It includes the total breakdown of the memory map, and as I expected I was way off. With the book now in-hand, I can start working on this trainer.