Challenge : The Most Minimal Breadboard 6502 Video Computer.

[Oneironaut]

I am all about challenges, and pushing the limits of what is currently considered possible!
This time, the end result might actually be something useful to 6502 newcomers.

No doubt, many of you will be able to point out examples that already exist, but before doing so, here are the absolute "rules" that I have decided to give myself for this challenge. None of these rules will be allowed to be broken in any way...


1) The ultimate score will be the final total chip count. Transistors will count as chips.
2) Every chip must be in a DIP package, and must press into a standard breadboard.
3) There must be a DIP 6502 used. MOS6502, WDC65C02, etc.
4) The "computer" must display Video. VGA, NTSC, LCD, etc.
5) The "computer" must produce Sound. Mono Stereo, Piezo, buzzer, MIDI, etc.
6) The 6502 code must be "loadable", and all support hardware to do so will go to chip count.
7) After chip count, the next deciding factor on "size" would be chip pin count.
8) The 6502 counts as chip number one!


So these are the rules!
Anyone want to give it a whirl or offer up an existing design?
I have a few untested ideas, and might have something to show over the holidays.


Rule (6) should probably get a little more explanation...

When I say "loadable", I mean that the computer should be able to run various programs to be useful. If it is going to be a game system then it should be capable of playing multiple games. If it is just a demo platform to learn 6502 assembly, then it should be easy to write new code and get it to run on the computer. If the support hardware required to load up the 6502 is not removable after bootup, then it will go against the chip count. So an AVR with an SD card would have to count as 2 chips. If it can be demonstrated that the loading hardware can be "hot pulled" after the 6502 boots up, then it will not count. An example of this would be a serial port that can be used to boot load the 6502 and then be disconnected.


Rule (4) - Definition of Video...

Video can be text or graphics in color or monotone. The video display device must be a standard appliance that anyone can get access to. If the video device is a non standard specialty item such as a "smart" LCD panel, then all ICs on that panel will go towards chip count. Obvious examples of standard video appliances would be VGA monitor, or Television Set. Hacking a standard display appliance will make it custom, and result in adding to the chip count!


Rule (5) - Definition of Sound...

Sound can be anything besides silence! Anything as complex as full stereo music or as simple as a monotone beep will be valid. The same rules apply to the sound as to the video - if a standard audio appliance is used, then it will not go to chip count. Examples are computer speakers or a line input on a TV.


Ok, let the fun begin.
Anything less than 10 chips will be impressive!


Cheers,
Radical Brad

[sark02]

Pairing the 6502 with a Propeller might be a good starting point.

http://hackaday.com/2014/06/01/propeddl ... ined-6502/

[Oneironaut]

Nice one.
Ok, that sets the bar at 9 chips then, since the programming dongle can be pulled after loading.

Brad

sark02 wrote:

Pairing the 6502 with a Propeller might be a good starting point.
http://hackaday.com/2014/06/01/propeddl ... ined-6502/

[sark02]

Oneironaut wrote:

Ok, that sets the bar at 9 chips then

In the rules you might want to specify that the 6502 must be used to execute the 6502 code... otherwise it might be permissible to remove some of those glue chips... leaving the 6502 on the board but electrically unconnected, with the Propeller (slowly) emulating a 6502...

[pnoyes]

I wouldn't consider my solution "Minimal", but it does satisfy most of the bullet points above:

https://hackaday.io/project/9325-dodo-6502-game-system


Almost all chips are DIP except for a FRAM chip on the game cartridge which is SMT. There is also an OLED module that has lots of SMT parts on it. Code is easily loadable, and sound is supported. For sound I am using the shift register on the 65C22, which helps to limit the chip count.

I think for a minimal chip count if not going with a propeller or similar I would use a SPLD from Atmel for the glue logic and whatever else:

http://www.mouser.com/ProductDetail/Atm ... CxBDeUM%3d

[Michael]

Only 65x02? No variants like 65x04 allowed?

[GARTHWILSON]

The 6504 should qualify, as it is a 6502 but just doesn't have all the connections brought out.

Donating to the cause, I have a couple of 15cm (6") color graphic LCDs I'll give to anyone who wants to pay the postage. They're roughly the size of a 3.5" floppy-disc drive. They're 20 years old but have never been used, and one still has the protective film over the viewable portion. They're Sharp model LQ6NC02, serial numbers 380541 and 423388. Each has a dozen tiny trimmers on the back for things like tint, contrast, horiz pos, etc.. They need a flex-circuit ribbon connector which I have only one of, which says on it, "AWM STYLE 20566 105°C, PARLEX CORP. 2193". They're about .9" thick over most of the area, and 1.25" at the thickest point where there's a small extra board on the back which I assume is a power supply for the back lighting which appears to be tiny fluorescent tubes. I hope someone can make good use of these. Someone gave them to me several years ago but I'll never use them.

[Hobbit1972]

Oneironaut wrote:

4) The "computer" must display Video. VGA, NTSC, LCD, etc.
...
Rule (4) - Definition of Video...

Video can be text or graphics in color or monotone. The video display device must be a standard appliance that anyone can get access to. If the video device is a non standard specialty item such as a "smart" LCD panel, then all ICs on that panel will go towards chip count. Obvious examples of standard video appliances would be VGA monitor, or Television Set. Hacking a standard display appliance will make it custom, and result in adding to the chip count!

Does "video" mean that the contraption produces some output even it is different kinds of snow? or does it need to be something discernable?


And - would you rate a standard oscilloscope as valid output device?

[GARTHWILSON]

Hobbit1972 wrote:

Does "video" mean that the contraption produces some output even it is different kinds of snow? or does it need to be something discernable?

Quote:

And - would you rate a standard oscilloscope as valid output device?

viewtopic.php?p=15348#p15348

[Oneironaut]

All good questions!

Yes, the 6502 must be executing 6502 code, and controlling the Video and Audio output.
Yes, any 650x variant will be acceptable, 6510, 6509, even 65816 would be fair.
Yes, video needs to be at least capable of a text that is readable on the screen!

The DODO game system is a very nice bit of work!
If you include the LCD backpack blob chips, what is the IC count?
I want to keep a running score card!

I may have to remove the ProPeddle though, as it does not seem to have sound.
Sound is a mandatory rule, even if just a simple one channel square wave.
I could not see any sound listed in the specs.

Brad

[DerTrueForce]

Do support components count towards the chip count? As in, does an ACIA baud rate crystal, or an IRQ\ diode or pull-up resistor count as a chip?

[Michael]

This is an interesting challenge and something I've thought about for a long time.

I think I might be able to do it with two chips; the 65C02 and a microcontroller. I've already got a design using a PIC microcontroller that will run a 65C02 at 1-MHz while mapping PIC resources (~4-kB RAM, 32-kB ROM, and PIC I/O) into 65C02 address space. I suspect I could add the capability to generate 40x25 NTSC video from a 1-kB block of RAM and decode a PS2 keyboard without too much trouble (sigh - if I only had the time).

Cheerful regards, Mike

[Oneironaut]

No passive components will count.
Also not counted will be crystals or oscillator modules, as long as that's all they do.
A transistor will count though. Same goes for a 3 pin reset IC, etc.

And the main thing to keep in mind... this is for DIP + Breadboard designs.

Brad

[pnoyes]

Oneironaut wrote:

All good questions!

Yes, the 6502 must be executing 6502 code, and controlling the Video and Audio output.
Yes, any 650x variant will be acceptable, 6510, 6509, even 65816 would be fair.
Yes, video needs to be at least capable of a text that is readable on the screen!

The DODO game system is a very nice bit of work!
If you include the LCD backpack blob chips, what is the IC count?
I want to keep a running score card!

I may have to remove the ProPeddle though, as it does not seem to have sound.
Sound is a mandatory rule, even if just a simple one channel square wave.
I could not see any sound listed in the specs.

Brad

Thanks Brad!

My IC count is 14 (Not counting the OLED at all)

Main Board:
LT1303-5
MAX202CPE
65C02
65C22
65C51
74HC00
74HC30
74HC138
AS6C62256A SRAM
AT28C256 EEPROM
DS1813

Game Board:
74HC14
2x SN74LVC245AN

[Oneironaut]

You read my mind!
I am actually shooting for a 2 chip system. one 65C02 and one AVR1284.

If my "too much time to think while I drive" calculations are correct, I should achieve the following...

- 6502 clocking in at 6 or 8 MHz.
- Color text display of 36x30 or 36x60 characters.
- 2 voice basic sound output.

Loading the 6502 will be fairly easy...

- Assemble a binary image and save it.
- Run my converter program.
- Load the AVR using the AVRisp-II.
- Disconnect, and let the 6502 fly!

It's not going to be much in the way of power, but will be a nice way for newcomers to get started with a 6502 on a breadboard.
As for the AVR, it is also a 40 pin DIP, same size as the 65C02.

I will post photos as I try to make this work.
Warning : Holiday drinking my cause distortions in the reality field!

Cheers,
Brad

Michael wrote:

This is an interesting challenge and something I've thought about for a long time.
I think I might be able to do it with two chips; the 65C02 and a microcontroller. I've already got a design using a PIC microcontroller that will run a 65C02 at 1-MHz while mapping PIC resources (~4-kB RAM, 32-kB ROM, and PIC I/O) into 65C02 address space. I suspect I could add the capability to generate 40x25 NTSC video from a 1-kB block of RAM and decode a PS2 keyboard without too much trouble (sigh - if I only had the time).
Cheerful regards, Mike