A2600Nano

The A2600Nano is a port of the MiSTer FPGA core components of the Atari 2600 VCS with enhancements from the A7800 core such as cartridge type autodetect and the video stabilizer for the:

Board	FPGA	support	Note
Tang Nano 9k	GW1NR	X	micro SD card HW modification needed
Tang Nano 20k	GW2AR	X	twin Dualshock MiSTeryShield20k spare header + Joy to DIP
Tang Primer 20K Dock ext Board	GW2A	X	twin Dualshock
Tang Primer 25K	GW5A-25	X	no Dualshock, no retro D9 Joystick
Tang Mega 60k NEO	GW5AT-60	X	twin Dualshock
Tang Mega 138k Pro	GW5AST-138	X	twin Dualshock

This project relies on a M0S Dock BL616 µC being connected to the Tang Nano 20K.
Alternately you can use a Raspberry Pi Pico or esp32-s2/s3 and use the FPGA companion firmware. Basically a µC acts as USB host for USB devices and as an OSD controller using a SPI communication protocol.

There is a nice case available mounting the MiSTeryShield20k (TN20k + M0S).

Original A2600 core by Retromaster
All HID, SDcard and µC firmware by Till Harbaum

Features:

• PAL 768x576p or NTSC 768x480p HDMI Video and Audio Output
• Scanline length auto adjust
• Cartridge type autodetect
• NTSC / PAL region autodetct
• Superchip autodetct
• USB Keyboard USB Keyboard
• USB Joystick
• USB Gamepad Stick as paddle emulation
  
• USB Mouse as paddle emulation
• supports 2nd Trigger Button for modified Games
• legacy D9 Joystick (Atari / Commodore digital type) MiSTeryShield20k
  
• Joystick emulation on Keyboard Numpad
  
• Dualshock 2 Controller Gamepad for MiSTeryShield20k via spare pinheader
• Dualshock 2 Controller Gamepad Keys & Stick as Joystick
  
• Dualshock 2 Controller Gamepad Sticks as paddle emulation (analog mode)
  
• Cartridge ROM loader. Boot default is homebrew 'Hunchy' Chris Walton

A2600Nano on Tang Nano 9K

See Tang Nano 9K

A2600Nano on Tang Primer 20K (Dock ext board)

See Tang Primer 20K

A2600Nano on Tang Primer 25K

See Tang Primer 25K

A2600Nano on Tang Mega 60k NEO

See Tang Mega 60K NEO

A2600Nano on Tang Mega 138k Pro

See Tang Mega 138K Pro

Installation

The installation of A2600Nano on the Tang Nano 20k board can be done using a Linux PC or a Windows PC Instruction.

Cartridge ROM Loader

ROM can be loaded via OSD file selection.

Supported mappers

• Auto detected (F8 F6 FE E0 3F F4 P2 FA CV 2K UA E7 F0 32)
  

LED 1 to 5 are activated as hint in case an unsupported game (mapper) detected

single / dual Button Joystick

• Button Trigger
• 2nd Button Trigger 2

Gamepad

• Gamepad Button Trigger A (DS2 circle) 1st Trigger Button

• Gamepad Button Trigger B (DS2 cross) 2nd Trigger Button

• Gamepad Button Trigger X (DS2 triangle) 1st Paddle Trigger and enable

• Gamepad Button Trigger Y (DS2 square) 2nd Paddle Trigger and enable

• Gamepad Button START as core function START
  

• Gamepad Button SELECT as core function SELECT
  

Note

Gamepad button keymap optimized for legacy USB Logitech RumblePad 2 or Dual Action. Keymap might differ for other Gamepads.

Paddle

• DualShock 2 (left Stick), USB Gamepad or USB Mouse.
  

1st Paddle 1st Gamepad use Trigger X (DS2 #1 triangle) or left Mouse Button

2nd Paddle 1st Gamepad use Trigger Y (DS2 #1 square) or right Mouse Button

3rd Paddle 2nd Gamepad use Trigger X (DS2 #2 triangle)

4th Paddle 2nd Gamepad use Trigger Y (DS2 #2 square)

Keyboard

• Key F11 as core function START
  
• Key PAGE UP as core function SELECT
  

Numpad		Numpad
0 Trigger	8 Up	. Trigger 2
4 Left	-	6 Right
-	2 Down	-

Push Button utilization

• S2 keep pressed during power-up to prevent FPGA bitstream load from FLASH.
  

• S1 reserved
  

OSD

invoke by F12 keypress

• Reset
  
• Cold Reset
  
• Audio Volume + / -
  
• Scanlines effect %
  
• Region switch Auto/NTSC/PAL
  
• HID device selection for Joystick Port
  
• Loader file selection
  
• Difficulty A, B Core switch
• Black & White Core video switch
• Joystick port swap
• Invert Paddle
• De-comb
• SuperChip Auto/off/on

Gamecontrol support

A 2nd Trigger Button (B) is supported for modified Games.

legacy single D9 Digital Joystick. OSD: Retro D9
or
USB Joystick(s) or Gamepad(s). OSD: USB #1 Joy or USB #2 Joy
Also RII Mini Keyboard i8 left Multimedia Keys are active if USB #1 Joy selected.
Button A and B Buttons as Trigger:

or
Dualshock 2 Gamepad Stick or Dpad as Joystick. OSD: DS #1 Joy or DS #2 Joy
At the moment Dpad only for original Pad. Some clone devices support at the same time Dpad and left stick simultaniously.
circle and cross Buttons as Trigger:

Important

In a MiSTeryShield20k configuration Dualshock is supported via the internal spare J8 pinheader.
See MiSTeryShield20k DS Adapter Cable for further information.

Note

TN20k: You have to select OSD "DS2 #2 Joy" for a MiSTeryShield20k configuration.
TN20k: You have to select OSD "DS2 #1 Joy" if you use the Sipeed Joy to DIP adapter.
Both DS interface ports can be active at the same time meaning twin Dualshock support if the MiSTeryShield20k MIDI interface is not populated (Resistor R9 and IC U3 removed).

or
Keyboard Numpad. OSD: Numpad

or
Mouse. OSD: Mouse
left Mouse Button and right Mouse Button as Trigger for Paddle 1 or 2.

or
USB Gamepad as Paddle. OSD: USB #1 Padd or USB #2 Padd
Trigger X and Trigger Y

or
Dualshock2 Gamepad left stick as Paddle. OSD: DS #1 Paddle or DS #2 Paddle

Trigger triangle and Trigger square

LED UI

LED	function	TN9K	TN20K	TP20K	TP25K	TM60K	TM138k
0	Cartridge selected	x	x	x	x	x	x
1	Game unsupported	x	x	x	x	x	x
2	Game unsupported	x	x	x	-	-	x
3	Game unsupported	x	x	x	-	-	x
4	Game unsupported	x	x	x	-	-	x
5	Game unsupported	x	x	x	-	-	x

LED 1..5 are activated as hint in case an unsupported game (mapper) detected

Multicolor RGB LED

• green      all fine and ready to go
  
• red          something wrong with SDcard / default boot image
  
• blue        µC firmware detected valid FPGA core
  
• yellow      FPGA core can't detect valid firmware
  
• white      -
  

Powering

Prototype circuit with Keyboard can be powered by Tang USB-C connector from PC or a Power Supply Adapter.

Synthesis

Source code can be synthesized, fitted and programmed with GOWIN IDE Windows or Linux.
Alternatively use the command line build script gw_sh.exe build_tn20k.tcl

HW circuit considerations

Pinmap TN20k Interfaces
Sipeed M0S Dock, digital Joystick D9 and DualShock Gamepad connection.

Pinmap D-SUB 9 Joystick Interface

• Joystick interface is 3.3V tolerant. Joystick 5V supply pin has to be left floating !
  

Joystick pin	IO	Tang Nano pin	FPGA pin	Joystick Function
1	2	J6 10	25	UP
2	1	J6 9	28	DOWN
3	4	J6 12	29	LEFT
4	3	J5 11	26	RIGHT
5	-	-	-	POT Y
6	0	J5 8	27	TRIGGER
7	-	n.c	n.c	5V
8	-	J5 20	-	GND
9	-	-	-	POT X

Pinmap Dualshock 2 Controller Interface

DS pin	Tang Nano pin	FPGA pin	DS Function
1	J5 18	71 MISO	JOYDAT
2	J5 19	53 MOSI	JOYCMD
3	n.c.	-	7V5
4	J5 15	-	GND
5	J5 16	-	3V3
6	J5 17	72 CS	JOYATN
7	J5 20	52 MCLK	JOYCLK
8	n.c.	-	JOYIRQ
9	n.c.	-	JOYACK

Getting started

In order to use this Design the following things are needed:

Sipeed M0S Dock or Raspberry Pi Pico RP2040 or ESP32-S2/S3
Tang Nano 20k
or Tang Primer 20K with Dock ext Board
and M0S PMOD adapter.
and PMOD DS2x2
or Tang Nano 9k
or Tang Primer 25k
and PMOD DVI
and PMOD TF-CARD V2
and PMOD SDRAM
and M0S PMOD adapter or ad hoc wiring + soldering.
or Tang Mega 60K NEO
and PMOD DS2x2
and M0S PMOD adapter
or Tang Mega 138k Pro
and PMOD DS2x2
and M0S PMOD adapter
microSD or microSDHC card FAT/exFAT formatted
TFT Monitor with HDMI Input and Speaker

HID and Gamecontrol Hardware option	TN20k needs	alternative option	Primer 25K	Mega 60K	Mega 138K Pro
USB Keyboard	USB-C to USB-A adapter	4 port mini USB hub HS8836A	x	x	x
USB Joystick(s)	4 port mini USB hub HS8836A	-	x	x	x
USB Mouse	4 port mini USB hub HS8836A	-	x	x	x
USB Gamepad	4 port mini USB hub HS8836A	-	x	x	x
Commodore/Atari compatible retro D9 Joystick	MiSTeryNano shield	D-SUB 9 M connector, breadboard to wire everything up, some jumper wires	-	adhoc SDRAM1 Joy D9	adhoc PMOD Joy D9
Dualshock 2 Controller Gamepad	Gamepad Adapter Board (Sipeed Joystick to DIP) respectively PMOD DS2x2	breadboard to wire everything up and some jumper wires	-	PMOD DS2x2	PMOD DS2x2