JCR-1541-II-1 - A Hybrid 1541 Disk Drive and C64 Emulator in Classic Form Factor

Features:

• Cycle exact Commodore 1541 disk drive emulator (via Pi1541)
• Can also be used as a C64 Emulator (via RetroPie)
• Supports serial bus chaining for connecting with other emulators or physical devices
• Power and activity leds
• Disk loading sounds
• Buttons and LED screen for changing loaded disk image
• External USB ports for easy connectivity (COMING SOON!)

See the table below for feature comparison between Pi1541 and C64 emulator modes.

Feature	1541 Disk Drive Mode	C64 Emulator Mode
Power led	supported	supported
Activity led	supported	not supported
Disk loading sounds	supported	not supported
LED screen	supported	supported
Front panel buttons	supported	supported
Disk images via USB	supported	not supported
HDMI output	supported	supported
USB joysticks	-	supported
Bluetooth joysticks	-	supported

Building Instructions

Requirements

In addition to the rest of the materials, you will need:

• A Raspberry Pi 3 Model B or B+
• Raspberry Pi USB Power Adapter. If using a third party adapter, make sure it has sufficient power output.
• microSD card

Building PI1541 Hat

Obtain necessary materials and build a PI1541 Hat:

• Order PCB: Pi1541 IO Adapter Rev. 4
• Gather required components
  • Most components documented at: https://www.hackup.net/2018/07/pi1541io-revision-4/
  • Exceptions:
    • SSD1306 OLED 128x32 instead of SSD1306 OLED 128x64
    • Straight push buttons instead of right-angle push buttons

Solder components and necessary headers:

• Build the hat according to Option B setup
• For pinout compatibility, solder LED screen to use bus 1

Software Setup: Pi1541

Obtain and install Pi1541: https://cbm-pi1541.firebaseapp.com/

Configure your Pi1541 to match your Pi1541 hat build (Option A or Option B setup; enable piezo buzzer)

If everything is done properly, you should be able to use

Printing the Case

Print all STL files contained in the case folder. Note that you need to print five buttons.

Post-process printed case as desired.

Wiring Pi1541 Hat to the Case

(TO BE ADDED)

Adding RetroPie Support

At this point, the device already works as a feature complete 1541 Disk Drive Emulator. With the following setup, the same physical device can also be used as a C64 emulator.

Install RetroPie

Obtain another SD card and flash it with RetroPie (v4.0.2 or later)

Configure OLED Display Support

For hardware pinout compatibility, make sure your PI1541 Hat is configured to use bus 1 (see table above).

pin	PI1541 Hat (Bus 0)	PI1541 Hat (Bus 1)	RetroPie OLED
GND	(any gnd pin)	(any gnd pin)	pin 6
5V	(any 5V pin)	(any 5V pin)	pin 4
SDA	pin 27	pin 3	pin 3
SDL	pin 28	pin 5	pin 5

Install C64 Emulator (Vice)

• Navigate to RetroPie Setup
• From optional packages, choose and install VICE

Using SSD1306 OLED 128x32

Install and configure RetroPie OLED version that has been specially adjusted for this use:

sudo apt-get update
cd /home/pi
git clone https://github.com/jsalonen/RetroPie-OLED.git
cd RetroPie-OLED
chmod 755 11.OLED.sh
sudo ./11.OLED.sh

End result should look like this:

Adding support for front panel buttons

Install https://github.com/mholgatem/GPIOnext in retropie terminal:

cd ~
git clone https://github.com/mholgatem/GPIOnext.git
bash GPIOnext/install.sh

Configure the buttons with wizard (as keyboard as controller, depending what you prefer)

Run as background deamon:

gpionext start

Reboot. When opening RetroPie, you should be able to use the buttons as a given controller

Pinout comparison table for reference:

Label	pin	GPIO	Pi1541 function	RetroPie function
Switch 1	pin 13	GPIO27	reset / select	joystick fire
Switch 2	pin 15	GPIO22	previous disk / move up	joystick up
Switch 3	pin 16	GPIO23	next disk / move down	joystick down
Switch 4	pin 07	GPIO04	exit folder	joystick left
Switch 5	pin 29	GPIO05	insert disk	joystick right
Reset	pin 38	GPIO20	reset	n/a

License and Credits

This project is provided "as is", without warranty of any kind.

The project includes adaptations of licensed works as follows:

• Case is adapted from Pi1541-II Case, by chrisjh. Licensed under Creative Commons - Attribution.
• RetroPie OLED library is based on RetroPie-OLED by Duritz, losernator, RiNa, Yanubis, 까먹구, et al. Licensed under GNU General Public License v3.0.