VIC20Nano

The VIC20Nano is a port of some MiST and MiSTer components of the VIC20 for the :

Board	FPGA	support	Note
Tang Nano 9k	GW1NR	HDMI / LCD	no C1541, Tape Mega-Cart. Only 8k or 16k memory expansion. micro SD card HW modification needed
Tang Nano 20k	GW2AR	HDMI / LCD	-
Tang Primer 20K Dock ext Board	GW2A	HDMI / LCD	-
Tang Primer 25K	GW5A-25	HDMI	no Dualshock, no Retro D9 Joystick
Tang Mega 60k NEO	GW5AT-60	HDMI / LCD	two Dualshock, selectable
Tang Mega 138k Pro	GW5AST-138	HDMI / LCD	two Dualshock, selectable
Tang Console 60K NEO	GW5AT-60	HDMI / LCD	twin Dualshock, no Retro D9 Joystick
Tang Console 138K NEO	GW5AST-138	HDMI / LCD	twin Dualshock, no Retro D9 Joystick

This project relies on a µC being connected to the FPGA. --> MiSTle-Dev wiki <--

Original VIC-20 core by MikeJ (Mike Johnson) and WoS (Wolfgang Scherr), C1541 by darfpga.
All HID components and µC firmware by Till Harbaum

Features:

• PAL 720x576p@50Hz or NTSC 720x480p@60Hz HDMI Video and Audio Output
• TFT-LCD module 800x600 SH500Q01Z + Speaker support
• USB Keyboard via µC (Sipeed M0S Dock BL616 / Raspberry Pi Pico RP2040 / ESP32 S2/S3)
• USB Joystick via µC
• USB Mouse via µC as c1351 Mouse emulation
• USB Gamepad Stick via µC as Paddle Emulation
• legacy D9 Joystick (Atari / Commodore digital type) MiSTeryNano shield
• Joystick emulation on Keyboard Numpad
• Dualshock 2 Controller Gamepad Keys & Stick as Joystick
• Dualshock 2 Controller Gamepad Sticks as Paddle Emulation (analog mode)
• emulated 1541 Diskdrive on FAT/extFAT microSD card
• C1541 DOS ROM selection
• Cartridge ROM (*.PRG) loader
• Direct BASIC program file (*.PRG) injection loader
• Tape (*.TAP) image loader C1530 Datasette
• Loadable 8K Kernal ROM (*.BIN)
• Mega-Cart (*.ROM) loader
• On Screen Display (OSD) for configuration and D64 image selection
• 3K, 8K, 16K, 24K, 32K RAM Expansion (35k with cardtridge RAM)
• 8K RAM at $A000 as loadable Cartridge Slot
• RS232 Serial Interface VIC-1011 to Tang onboard USB-C serial port or external hw pin.

Installation

The installation of VIC20 Nano on the Tang Nano 20k board can be done using a Linux PC or a Windows PC Instruction.

VIC20Nano on Tang Nano 9K

See Tang Primer 9K

VIC20Nano on Tang Primer 20K (Dock ext board)

See Tang Primer 20K The DDR3 memory controller is a slight modified copy of nestang. It had been tested on a board eqipped with a SKHynix DDR3 memory and is used as a buffer for the TAP Tape loading.

VIC20Nano on Tang Primer 25K

See Tang Primer 25K. PMOD TF-CARD V2 is required !

VIC20Nano on Tang Mega 60k NEO

See Tang Mega 60K NEO

VIC20Nano on Tang Mega 138K Pro

See Tang Mega 138K Pro

VIC20Nano on Tang Console 60k / 138k NEO

See Tang Console 60K / 138K NEO

VIC20Nano with LCD and Speaker

See Tang Nano LCD

emulated Diskdrive c1541

Emulated 1541 on a regular FAT/exFAT formatted microSD card. Copy a D64 Disk image to your sdcard and rename it to disk8.d64 as default boot image. Add further D64 images as you like and insert card in TN/TP slot. LED 0 acts as Drive activity indicator.

RAM Expansion

Size and Region can be activated in several steps. A change takes effect immediately. Take care to activate the correct size of needed expansion before you load .PRG and .TAP !

Expansion	$0400 3k	$2000 8k	$4000 8k	$6000 8k	$A000 8k
Block	0	1	2	3	Cartridge
3k	x	-	-	-
8k	-	x	-	-
16k	-	x	x	-
24k	-	x	x	x
35k	x	x	x	x	x

Cartridge ROM Loader (.PRG/.CRT)

Cartrige ROM can be loaded via OSD file selection. Be aware that the core doesn't support the VICE EMU file format. Typical VIC20 Cartridge ROMS with ending .PRG have a two byte header indicating the loading location. 8k Cartridges to be loadeded directly as such. 16k or larger Cartridges have to be loaded in several steps and the file with ending xyz-a000.prg have to be loaded last. First load xyz-2000.prg, xyz-4000.prg or xyz-6000.prg and then xyz-a000.prg at last. The Cartridge will start after that last step automatically. Copy a 8K xyz-a000.prg ROM to your sdcard and rename it to vic20crt.crt as default boot cartridge.

BASIC Program Loader (.PRG)

A BASIC Program .PRG file can be loaded via OSD file selection. Copy a .PRG to your sdcard and rename it to vic20prg.prg as default boot basic program. Prevent PRG load by OSD PRG selection No Disk , Save settings and Reset.

Tape Image Loader (*.TAP)

A Tape *.TAP file can be loaded via OSD file selection In order to start a tape download choose VIC20 CBM Kernal (mandatory as JiffyDOS doesn't support Tape). Best to save Kernal OSD selection via Save settings.

The file is loaded automatically as soon as TAP file selected via OSD (no need to press PLAY TAPE button) in case no TAP had been previously selected. After some seconds the filename of the to be loaded file will be shown and it will take time... Copy a *.TAP to your sdcard and rename it to vic20tap.tap as default tape mountpoint. For Tape unload use OSD TAP selection No Disk and Reset or System Cold Boot.

Kernal Loader (.BIN)

The CBM factory PAL type is the power-up default Kernal.

Kernal ROM files *.BIN can be loaded via OSD selection (e.g. JiffyDOS VIC20). Copy a 8K VIC20 Kernal ROM .BIN to your sdcard and rename it to vic20kernal.bin as default boot Kernal. Prevent Kernal load by OSD Kernal BIN selection No Disk and Save settings and do a power-cyle of the board.

loadable Cartridge RAM Slot

Some Cartridge based games can be be simply loaded from a VIC20 D64 Disk Image. Example: 16 k Cartridge Game Enable RAM Expansion at $2000 (or $6000) and Cartridge region $A000 Leave OSD setting CRT writeable setting as enabled as first approach. Save setting and do a Cold Boot Reset. ``` LOAD "xyz.200",8,1``` (Block 1) ``` or LOAD "xyz.600",8,1``` (Block 3) ``` LOAD "xyz.A00",8,1``` (Block 5) Start Game by command: SYS40960 (general start Address for Cartridge Slot) or better perform a Reset via OSD. There are also some cartridge games on D64 Image with a loader that themselves further reload the needed RAM regions and autostart (you have to activate RAM regions beforhand). A loaded Cartridge can be exited by disabling memory region$A000 + Cold Reset via OSD. In order to trial another game just activate again (after reset !) the $A000 memory and load another game.

Mega-Cart (.ROM)

The 2MB Mega-Cart *.ROM can be loaded via OSD file selection. If the Mega-Cart is used, then managing the RAM expansion configuration is done in its menu. NVRAM is not supported.

Core Loader Sequencing

The core will after power cycle/ cold-boot start downloading the images on the sdcard in the following order:

Push Button / DIP Switch utilization

• Nano 20k S2 keep pressed during power-up for FLASH programming of FPGA bitstream
• Primer 20k: There is by default unfortunately no Button/Switch to prevent FPGA bitstream load from FLASH (see rework how to add).
• S2 open OSD

• S1 reserved

OSD

invoke by F12 keypress

• Reset
• Cold Reset
• Audio Volume + / -
• Scanlines effect %
• Widescreen activation
• Screen centering
• PAL / NTSC Video mode
• HID device selection for Joystick Port
• RAM Expansion A000(8k), \6000(8k), $4000(8k), $2000(8k), $0400(3k)
• Cartridge Write protection
• c1541 Drive disk image selection
• c1541 Disk write protetcion
• c1541 Reset
• c1541 DOS ROM selection
• Loader (CRT/PRG/BIN/TAP/ROM) file selection
• Cartridge unload

Gamecontrol support

legacy single D9 Digital Joystick. OSD: Retro D9

USB Joystick(s). OSD: USB #1 Joy or USB #2 Joy

Gamepad Stick as Joystick. OSD: DualShock2
stick digital for Move and Left L1 or Right R1 shoulder Button for Trigger or following Pad controls:

Buttons	-	-
Left L1/R1Trigger	triangle buttonUp	.
square buttonLeft	-	circle buttonRight
-	cross buttonDown	-

Keyboard Numpad. OSD: Numpad

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

Mouse. OSD: Mouse
USB Mouse as c1351 Mouse emulation.

Dualshock2 Gamepad as Paddle. OSD: DS2 Paddle
Dualshock 2 Sticks in analog mode as VC-1312 Paddle emulation. Left L1 / L2 and Right R1 / R2 shoulder Button as Trigger You have first to set the DS2 Sticks into analog mode by pressing the DS2 ANALOG button. Mode indicated by red light indicator.Configure DIGITAL mode (press ANALOG button again) when using the Joystick mode again and set OSD: DualShock

USB Paddle. OSD: USB #1 Padd or USB #2 Padd
Left Stick in X / Y analog mode as VC-1312 Paddle emulation. Button 1 / 2 as Trigger

Keyboard

Tape Play not implemented.

LED UI

LED	function	TN20K	TP20K	TP25K	TM60k	TM138K Pro	TN9k
0	c1541 activity	x	x	x	x (done)	x	N/A
1	D64 selected	x	x	x	x (ready)	x	N/A
2	CRT seleced	x	x	-	-	x	x
3	PRG selected	x	x	-	-	x	x
4	Kernal selected	x	x	-	-	x	x
5	TAP selected	x	x	-	-	x	N/A

Solid red of the c1541 led after power-up indicates a missing DOS in Flash

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      -

RS232 Serial Interface

The Tang onboard USB-C serial port can be used for communication with the Userport Serial port VIC-1011. Terminal programs need the Kernal serial routines therefore select via OSD the CBM Kernal. For a first start use 1200Baud and a Terminal program like VIC term and on the PC side Putty. OSD selection allows to change in between TANG USB-C port or external HW pin interface.

Board	RX (I) FPGA	TX (O) FPGA	Note
TN20k	31	77	pinmap, misterynano io(6) / io(7)
TP25k	K5	L5	J4-6 J4-5, share M0S Dock PMOD
TM60k NEO	AB20	AA19	J24-6 J24-5, share M0S Dock PMOD
TM138k Pro	H15	H14	J24-6 J24-5, share M0S Dock PMOD

Remember that in + out to be crossed to connect to external device. Level are 3V3 tolerant.

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, build_tp20k.tcl or build_tp25k.tcl

Pin mapping

see pin configuration in .cst configuration file

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
Sipeed Tang Nano 20k
or Sipeed Tang Primer 25k
and PMOD DVI
and PMOD TF-CARD V2
and SDRAM
and M0S PMOD adapter
or ad hoc wiring + soldering. or Tang Primer 20K with Dock ext Board
and M0S PMOD adapter
and PMOD DS2x2
or Tang Nano 9K
or Sipeed Tang Mega 138k Pro
and SDRAM
and PMOD DS2x2
and M0S PMOD adapter
or Tang Mega 60K NEO
and SDRAM
and PMOD DS2x2
and M0S PMOD adapter

microSD or microSDHC card FAT/exFAT formatted
TFT Monitor with HDMI Input and Speaker