Vectrex Clone blog

New firmware was created for my Vectrex
resolution in X axis was doubled than currently I have 512×480 pixels
next step will be increase brightness levels (currently 4, planned 16).

Bellow is picture from first test with beamer :-)

This instructions are based on www.harmlesslion.com/text/vectrex_multicart.htm

When I was constructing my Vectrex clone I need some easy cart for testing. This was easier description how to create you own cart.
Than I take first FLASH which I have at home, look if this is compatible and make design based on mentioned web pages.
In my design is only:

• FLASH A29040B-70F
• DIP Piano
• 8× 1K 1206 SMD Resistor
• 2X 100n 1206 capacitor

This design support 8kB and also 32kB images of games
till now I only used original binary file from link and than I can play abou 36 games.

attached to this post is PDF with circuit diagram (resistor network is instead of dipswitches :-) ), PCB design (double sided) and bin file for FLASH.

All parts was ordered from Farnell.
For programming I used very cheap but very nice programmer Genius G540 from Ebay.

Circuit diagram
PCB layout
Bin File for FLASH

15.4.2011

After some days when I have to work, is time to work on Vectrex Clone.
Jobs done:

• add X, Y and Z offset poti
• made backpanel for miniitx box
• some work on firmware
• put everything together into box

and result is here:

Cart slot will be fixed in space for CD drive

Still lot of work to do … but after firmware will be tuned it will be very nice replacement for original Vectrex :-)

6.4.2011

As I mentioned few posts ago, for Joysticks I want to use PS2 controlers.
Two of them allready arrived.

Result is this:
It is better than I expected, pots inside are right value (10Kohms).
Than modification for Vectex is change cable (from 8 to 9 wires), cut tracks on board inside controller and solder new ones.
Thats it.

Picture of modification will be added later.

6.4.2011

bussines trip at Munich

New version of firmware made after two weissbiers.
Looks much better, deleting of page works.

4.4.2011

Few hours with ISE and I am able to read ADCs, and somehow write it to memory. But something is still wrong, probably timing, and also clearing new memory.

My strategy for firmware is this:

• divide memory to 4 pages
• during drawing VGA clear page for next vectors
• draw vectors directly by using DAC output as row and column
• swap pages after each sync

Following video is actual result

2.4.2011

Now start hard work.
Generate timing for VGA is not so big problem, at internet is lot of examples and also very nice page with timing info for most of standart resolutions.
I use at begining 640×480 at 60Hz, for future is planned minimum 800×600.

After few hours of fighting with ISE and VHDL I have stable image, with data from not deleted SRAM.

As you can see at picture. For more I do not have currently energy and time :-(

1.4.2011

As you probably know, step from circuit diagram to real PCB is for me not so big deal, than we have PCB, allready populated :-)

28.3.2011
Target is clear!

I have to make device which will:

1. read memory to generate VGA
2. write to memory vectors from AD convertes
3. convert XY and Z (brightness) to digital

For this I select following parts:

• CPLD XC95144XL with 144 pins
• SRAM 256kx16bits
• ADC two AD9218 with max sample rate 40MPS
• OP amps AD8137
• 50MHz oscilator

with this parts I create attached circuit.
It looks easy, but firmware will be more tricky :-)

Rasterizer circuit diagram

During thinking about Vectrex clone, I of course think what should I use as display. Idea with lasers was of course most “cool” but to be honest, I only hope that lasers will be fast enought.
As you see result, they are not.

Than what was my backup plan?

First was to make some device which will draw vectors to memory and than display it as normal image (VGA will be best).
Second was clone also CRT part of Vectrex.

My choice is first one, I do not want to build televison, vectrex will be small, probably will work with normal monitors, maybe beamers :-)

Than my plan is this connect together:

• fast analog to digital convertes
• fast SRAM
• CPLD or similar device

Result will be something what I call Rasterizer.
Sounds easy, right?