WonderTANG

TangNano 20K cartridge for MSX computers

This cartridge allows any MSX computer to host a Sipeed Tang Nano 20K. The current fpga core implements:

• MicroSD Nextor 2.1 Drive
• FM OPLL + MSX Music ROM
• 2MB Super Mega RAM SCC+
• 4MB Memory Mapper
• Sega Master System VDP + PSG to allow running SMS roms from SofaRun (Franky HDMI)

The Super Mega RAM SCC+

The Super Mega RAM SCC+ is a different ACVS-like MegaRam that support different mappers:

• Konami4 (2MB)
• Konami5 SCC+ (512KB)
• ASCII8 (2MB)
• ASCII16 (2MB)

Use the utility SMRAM.COM to allow using different mappers as well activating the SCC+, otherwise it will just work like an ordinary MegaRAM 2MB.

Board Revisions

The latest available version is V2.0b. Please, use that version to order new boards.

[!IMPORTANT] Always check your board revision when assembling or programming your WonderTANG.

The revision number is available on the front-left side of the board.

Download the specific FPGA Bitstream version required by your board version.

V2.0a/V2.0b (NEW)

This is the new version using Tang Nano 20K internal DAC amplifier.

Changes since last revision:

• uses internal DAC for audio output
• switches to a flatter audio connector
• removes jumpers
• requires the latest FPGA bitstream version

V2.0a is equivalent to V2.0b.

|<img src="images/WonderTANG-V2.0a-front-build.jpg" width="768"/>| |:--| |V2.0a prototype build|

|<img src="images/WonderTANG-V2.0b-front-render.png" width="512"/>|<img src="images/WonderTANG-V2.0b-back-render.png" width="512"/>| |-|-| |V2.0b front render|V2.0b back render|

PCB

You can access V2.0b gerber files from github at:

https://github.com/lfantoniosi/WonderTANG/tree/4a21359a5136a5a96363da55edc5d934acfd37c5/kicad/gerber

I recommend JLCPCB: https://jlcpcb.com/

Bill of Materials

| Reference | Value | Description | Qty | Link | |-----------------------------|----------------------------|------------------------------------------------------|-----|-------------| | C5, C6, C7, C8, C9, C10, C11, C12 | DIP-100NF | MLCC Monolithic Ceramic Capacitor DIP 100nF (104) | 8 | AliExpress | | C1, C2 | ELEC-DIP-4.7UF-16V | Electrolytic Capacitor DIP 4.7uF 16V | 2 | AliExpress | | C13 | ELEC-DIP-10UF-16V | Electrolytic Capacitor DIP 10uF 16V | 1 | AliExpress | | R5,R6 | DIP-2.2K | Resistor PTH 2.2KR | 2 | Aliexpress | | R1 | DIP-330R | Resistor PTH 330R | 1 | AliExpress | | R4 | DIP-4.7K | Resistor PTH 4.7KR | 1 | AliExpress | | D1 | LED-3MM | LED 3MM Red | 1 | AliExpress | | D2 | 1N5817 | SCHOTTKY BARRIER RECTIFIER DIODE | 1 | AliExpress | | U1, U2, U3, U4, U6 | SOCKET-DIP-NARROW-20 | DIP Socket Narrow 20 pins | 5 | AliExpress | | U1, U2, U3, U4, U6 | SN74LVC245AN | OCTAL BUS TRANSCEIVER WITH 3-STATE OUTPUTS | 5 | See note | | Q1,Q2 | 2N3904 | 2N3904 NPN switching Transistor | 2 | AliExpress | | J2 | CP1-3523N | CONN JACK STEREO 3.5MM R/A | 1 | AliExpress | | J3 | Mini Micro male/female JST | Mini Micro male/female JST | 1 | AliExpress | | U5 | Tang Nano 20K | Tang Nano 20K | 1 | AliExpress |

Build Notes

The audio J3 needs to be soldered into the TANG Nano 20K speaker pins (two small pins between the words SiPEED and TANG NANO 20K, polarity does not matter). Use the JST connector or solder it directly under the board.

<img src="images/WonderTANG-V2.0a-front-build-audio-connector.jpg" width="512"/>

74LVC245AN

Be aware of fake 74VLC245 sold from Chinese vendors like AliExpress or UTSource. There are reports of they being 74LS245 rebranded as LVC which does not work. You need genuine 75LVC245. Buy then from DigiKey, Mouser or Adafruit.

V1.02d (PREVIOUS)

[!WARNING] If you are building new boards, please use the latest available board revision instead.

This version fixes a problem with Philips MSX machines (detected on Philips VG8235 and Philips NMS8245) by properly implementing the MSX cartridge nINT signal as an open-collector.

Changes since last revision:

• uses a transistor to implement nINT as open-collector
• requires a specific FPGA bitstream version

|<img src="images/WonderTANG-V1.02d-front-render.png" width="384"/>|<img src="images/WonderTANG-V1.02d-back-render.png" width="384"/>| |-|-| |V1.02d front render|V1.02d back render|

PCB

You can access V1.02d gerber files from github at:

https://github.com/lfantoniosi/WonderTANG/tree/0e938fb70acad34c753a95fd54bb3fdd6095d590/kicad/gerber

Bill of Materials

| Reference | Value | Description | Qty | Link | |-----------------------------|----------------------------|------------------------------------------------------|-----|-------------| | C5, C6, C7, C8, C9, C10, C11, C12 | DIP-100NF | MLCC Monolithic Ceramic Capacitor DIP 100nF (104) | 8 | AliExpress | | C1, C3, C13 | ELEC-DIP-10UF-16V | Electrolytic Capacitor DIP 10uF 16V | 3 | AliExpress | | C2, C4 | DIP-1UF | MLCC Monolithic Ceramic Capacitor DIP 1uF (105) | 2 | AliExpress | | R2, R3 | DIP-47R | Resistor PTH 47R | 2 | AliExpress | | R5,R6 | DIP-2.2K | Resistor PTH 2.2KR | 2 | Aliexpress | | R1 | DIP-330R | Resistor PTH 330R | 1 | AliExpress | | R4 | DIP-4.7K | Resistor PTH 4.7KR | 1 | AliExpress | | D1 | LED-3MM | LED 3MM Red | 1 | AliExpress | | D2 | 1N5817 | SCHOTTKY BARRIER RECTIFIER DIODE | 1 | AliExpress | | U1, U2, U3, U4, U6 | SOCKET-DIP-NARROW-20 | DIP Socket Narrow 20 pins | 5 | AliExpress | | U1, U2, U3, U4, U6 | SN74LVC245AN | OCTAL BUS TRANSCEIVER WITH 3-STATE OUTPUTS | 5 | See note above | | Q1,Q2 | 2N3904 | 2N3904 NPN switching Transistor | 2 | AliExpress | | C13 | ELEC-DIP-10UF-16V | Electrolytic Capacitor DIP 10uF 16V | 1 | AliExpress | | C1, C2 | ELEC-DIP-4.7UF-16V | Electrolytic Capacitor DIP 7.7uF 16V | 2 | AliExpress | | J1, J3 | PH-254-S-M-40-BLACK | 2.54mm 1 x 40 Pin Male Single Row Pin Header Strip Black | 1 | AliExpress | | J2 | SJ1-3533NG | SJ1-3533NG Audio P4 3 Pin connector | 1 | AliExpress | | U5 | Tang Nano 20K | Tang Nano 20K | 1 | AliExpress |

V1.01c (OBSOLETE)

[!WARNING] If you are building new boards, please use the latest available board revision instead.

This version corrects an audio problem due to wrong connection of AUDIO and SOUNDIN capacitors.

Changes since last revision:

• fix audio output
• requires an old FPGA bitstream version

[!IMPORTANT] This version is known to experience problems with some Philips MSX machines.

|<img src="images/WonderTANG-V1.01c-front-render.png" width="384"/>|<img src="images/WonderTANG-V1.01c-back-render.png" width="384"/>| |-|-| |V1.01c front render|V1.01c back render|

PCB

You can access V1.01c gerber files from github at:

https://github.com/lfantoniosi/WonderTANG/tree/b9e608418bb1917098046716af13b877def6737b/kicad/gerber

Or you can order V1.01c PCBs directly from:

[https: