Awaiting the Control Block ...

Finished the soldering and mounted the controller ports. Turns out there were 80 (!) wires in the cable - 40 data and 40 ground in twisted pairs. I removed the ground wires and after connecting 30 wires, 10 remain for repairs.

Custom Arcade Controllers

While we have used the USB SNES like controllers the past week, I've been ruminating on better and more accurate controllers for a more enjoyable gameplay.

I ordered a RetroPie Control Block, which is on back order. Apparently, they had some mix up with the batch that was recently delivered. That board attaches to the GPIO header and will control the power to the Pi as well as break-out two arcade controllers.

I needed to find a high-density and robust connector to interface the external arcade controllers to the Control Block.  The CB provides 2 channels of 16 switches - requiring 17 pins (16 switches and a ground).  The best compromise I found was to use a 15 pin D-SUB connector, familiar to most of us as the standard VGA connector.  That provides 14 switches for each controller (14 switch and 1 ground pin).  Theoretically, I could use the shield of the connector as a 15th connector, but that's not good practice.

The nice thing here is that the connectors will fit perfectly in the holes for the 2 Atari joystick ports.  Those are 9 pin D-SUB connectors, the same physical size as the 15 pin ones.  It will also allow some continuity with the original Atari 600XL usage - that the controllers are properly labeled (unlike the situation on the backside).

I found a nice bundle of connector wires in the form of an old PATA cable.  I believe there are 40 discrete wires in this bundle.  Now on to solder 30 connections!

Keyboard Interface Update

Someone asked me how this is going, so I thought I'd post an update. I almost got it working before things got shutdown for Christmas. But alas, not enough time to debug. I finished 99% of the soldering and connected the Teensy 2.0 to my Linux workstation, loaded a couple of sample HEX programs. One blinks the LED, which you see in the photo. So that is working. I loaded the Arduino IDE and the Teensy extensions, but could not get the code to compile. Looks like it's not the mods I made. The code Pixelpracht provided would not compile either. Looks like it's missing header library calls. I'll have to debug it next week. I will reach out to Pixelpracht and see if I can get some direction. One thing I'd like to know is why his code includes a matrix with 23 of the 24 Atari keyboard lines and not the 22 I think it should be. One (19) is not connected, giving 23, but the 24th trace also is not connected, as it goes to the power LED. I plan to feed that from the RetroPie Control Block. 

Internal audio amplifier and speakers

Found a cheap ($5) stereo audio amplifier on eBay, with the right size speakers and 5V input. Disassembled and installed into the 600XL. Will put a jack eventually on the back, so that a short jumper can run from the output of the Pi to the amplifier (rather than running the input out the back as it is now. Also, the 5VDC input is temporarily off the GPIO header, until the Control Block arrives. Power will then come off the Control Block master. 

Introducing the project to my boys (2015.11.25)

Here's an intro video, where I describe to my boys what we are doing.

Teensy Placement, Initial Power-Up, and the Control Block

The PC project board and headers arrived today, so I'm playing with placement of the interface circuit. Probably going to attach it to the back of the keyboard, as there is a nice flat metal surface to which to attach double-sided tape. The limiter is the existing plastic Atari keyboard header. It's 32 years old, so I don't want to put a lot of stress on it - which precludes mounting the circuit in the bottom half of the case.

Oh, and I connected the Pi through the HDMI-VGA interface and powered it up yesterday.  Works great so far.  I discovered the 8GB SD card is listed as questionable in compatibility (though it worked OK), so I decided to replace it with a 32GB class 10 Samsung EVO card... it was only $11.  That way, we can load every last bit of whatever we want on it.

Also put in a pre-order for the RetroPie Control Block ($45 with shipping).  That will mean adding 1 additional hole on the back for the mini-USB port.  This is the power port that must be used, as the Control Block has soft-power functionality that will feed the Pi.  It also allows adding a power switch and status LED.  I will use the LED on the Atari keyboard for that.  Will try the existing lame red LED, which I verified is working.

Best RetroPie initial setup how-to

There are several good how-tos floating around concerning setting up the Raspberry Pi for RetroPie.  This is the best one, IMO.

Status update on the Control Block

The RetroPie Control Block is available for pre-order.  Great!  While I'm awaiting its arrival, I will focus on the keyboard interface sub-project.

Hooking up the external ports

With the Raspberry Pi and ports all being well-epoxied in place, it was time to connect the extension cables for the USB and Ethernet ports.

The Teensy 2.0 is also plugged into the external port that will serve as the keyboard USB out.  The Teensy will have some headers soldered onto it and these will in turn be soldered to another project board, for interfacing with the Atari keyboard connector.

Ethernet back panel port

The Ethernet extension cable also arrived yesterday, so I installed that where the power switch used to be. Same deal: cut off one of the mounting flanges, widened part of the hole, and expoxied it in place. Just have the USB port for the Teensy keyboard conversion device and that will be it for the initial spate of connectors!

Seating the Raspberry Pi

The nylon standoffs arrived yesterday, so I installed the Raspberry Pi today. I found a pack of 100 M2.5 12mm standoffs for $10 on Amazon with Prime shipping. I used 2 of the 12mm standoffs as-is for the rear legs and cut about 5mm off of each of the front 2. I used the same 2 part epoxy gel I used to mount the USB ports. Easy peasy. The standoffs are great because they have both a male and female side, so you can use another standoff as a nut. 

Here's a cool summary of the systems covered by RetroPie, in chronological order!

Arcade Systems, Game Consoles, and Home Computers in RetroPie

YEAR OF RELEASE	PICTURE	NAME	TYPE	EMULATOR
1977		Atari 2600	Game Console	Stella(RetroArch)
1977		Apple II	Home Computer	LinApple
1977		Commodore PET	Home Computer	Vice
1979		Atari 800	Home Computer	Atari800
1979		Intellivision	Game Console	jzintv
1979		Z-machine	Virtual Machine	Frotz
1980		Commodore VIC-20	Home Computer	Vice
1981		IBM PC	Home Computer	rpix86
1982		Commodore C 64	Home Computer	Vice
1982		Commodore CBM-II	Home Computer	Vice
1982		Vectrex	Game Console	Vecx(RetroArch)
1982		ZX Spectrum	Home Computer	Fuse FBZX
1983		MSX	Home Computer	OpenMSX
1983		Nintendo Entertainment System	Game Console	FCEUMM(RetroArch)
1984		Apple Macintosh	Home Computer	Basiliks II
1984		Amstrad CPC	Home Computer	CPC4Rpi
1984		Commodore Plus/4	Home Computer	Vice
1985		Commodoce 128	Home Computer	Vice
1985		Commodore Amiga	Home Computer	UAE4ALL
1985		Atari ST	Home Computer	Hatari
1985		Sega Master System	Game Console	Picodrive(RetroArch)
1985		Sega System 16	Arcade	Final Burn Alpha
1987		TurboGrafx-16	Game Console	Mednafen(RetroArch)
1988		Sega Genesis	Game Console	Picodrive(RetroArch)
1988		CP System	Arcade	Final Burn Alpha
1989		Atari Lynx	Handheld	Handy(RetroArch)
1989		Game Boy	Handheld	Gambatte(RetroArch)
1990		Sega Game Gear	Handheld	Osmose
1990		Neo Geo	Arcade	Final Burn Alpha
1990		Super Nintendo Entertainment System	Game Console	PocketSNES(RetroArch)SNES9X PiSNES
1991		Sega CD	Game Console	[Picodrive(RetroArch)
1993		CP System II	Arcade	Final Burn Alpha
1994		Sega 32X	Game Console	Picodrive(RetroArch)
1994		Sony Playstation	Game Console	PCSX Rearmed(RetroArch)
1996		CP System III	Arcade	Final Burn Alpha
1996		Nintendo 64	Game Console	Mupen64plusMupen64plus-libretro
1998		Game Boy Color	Handheld	Gambatte(RetroArch)
2001		Game Boy Advance	Handheld	GPSP
2001		ScummVM	Virtual Machine	ScummVM
2004		C64 Direct-to-TV	Game Console	Vice