PCB Layout In Progress...

I'm still slowly working on the board in my free time.  I've recently started on a new PCB layout to test out component placing and connector fittings.  The placement of the expansion port on the prototype meant I couldn't connect a large cartridge like a 1750 REU and the video at the same time.

Replacement Clock Generator Chip

I found a fully programmable clock chip that can replace the 8701 and will generate the right frequencies for NTSC and PAL for both the color and dot clocks.  Changing between NTSC and PAL will still require a different fundamental crystal and toggling some DIP switches, but I can place both crystals on the board and have a jumper to select between the two.  Below is my breadboard test with the chip.

C64 Expansion Port Connector from Sullins

I've been looking for a vendor that supplied an edge connector that was identical to the one in the C64.

At CommVex, Tim Waite suggested I check Sullins and see what they sell.  I was able to find the right part and get a sample.  The sample arrived today and it's a perfect fit. 

The part number is: EBC22DCAN-S189

I'm waiting to get a quote back on what the pricing would be from them.

USB keyboard update

I'm working on a 3 chip solution to interface a USB keyboard with the 64.  I'm testing out an ATmega chip as the USB host couple to an Analog Devices ADG2128 8x12 analog switch.  It's a very similar setup to the C= Key PS2 adapter boards.

I'm waiting for the sample of the switch chip to show up next week to begin testing.

List of Feature Requests

Below is a list of features that were requested by people at CommVex I'm working to integrate into the board.  Thanks to everyone for their interest and input into making the board better!

• USB keyboard interface
• Dual SID chip support
• Internal IEC header to support 1541 drive emulators (also add header for parallel port lines for super-speed)
• Add the cassette port back in (omitted in prototype)
• A bunch of power headers (the board can supply 3.3V, 5V, 9V, 12V rails)
• USB headers for front and rear USB ports on the case for 5V power
• RAM expansion on the motherboard
• Amiga clock port
• On-board ethernet adapter (RRNet or equivalent)
• Dip switches for address remapping
• A super header that would bring out more signals that aren't on User/Expansion ports for different projects

Schematic Rev 0.6

I'm posting the schematic of my prototype board for those interested in seeing what changes have been made from the B-3 rev C64 board.

https://drive.google.com/file/d/0B3Jx8cdecGvPeV9IWWtFR3hremc/edit?usp=sharing

Presentation Slides from CommVex

Below is the link to my presentation slides about the board that I presented at CommVex.

https://drive.google.com/file/d/0B3Jx8cdecGvPb1NRYmpSdURjTGc/edit?usp=sharing

First Post!

I will be posting info here about my Micro ATX replacement board for a Commodore C64.  I will post updates and changes as I get the board ready for a larger production run.  All suggestions and requests for features are welcome!!

The working prototype board was presented at CommVex 2014 in Las Vegas.