wonder9968

This is a proof of concept instantiation of the V9968 RTL by Takayuki Hara (HRA!) on the WonderTANG! boards by Luis Felipe Antoniosi.

Takayuki Hara has created a prototype cartridge for developing the V9968 VDP for the MSX2++ computer.

Shinobu Hashimoto has ported the RTL of the V9968 to his own tnCart board, which is very similar to the WonderTANG! board by Luis Felipe Antoniosi.

Finally, as a proof of concept, I (Albert Herranz) have ported Shinobu Hashimoto's own port of the V9968 to the widely available WonderTANG! to be able to have a quick glimpse of the V9968 capabilities as demonstrated in the DEVCON 14, without the need to build HRA!'s V9968 prototype board nor the tnCart.

Warning

This is just a proof of concept, use at your own risk.

This port is unsupported and it probably won't be updated, as the V9968 is still in development.

Note

Successfully tested on a Tides Rider MSX2+, Panasonic FS-A1WSX, Omega MSX2+, Philips VG-8235, Sony HB-501F and JFF TMSHAT.

Caution

Please, DO NOT use modified wonder9968 RTLs with ports 98h/99h on your MSX unless you first physically deactivate your MSX internal VDP (i.e remove it or force it to ignore IO reads/writes from/to 98h/99h if it must be kept connected).

Otherwise, you risk damaging your MSX and/or your WonderTANG! You've been warned!

Differences

The V9968 port to the WonderTANG! uses the native 27MHz of the Tang Nano 20K as a source clock to construct the rest of the cartridge clocks, including the base and sdram clock, and the DVI TX associated clocks. This improves the video quality, which experiences synchronization issues when using the cartridge clock as a source clock.

It also adapts the RTL to the pin mappings and the specific signal mux of the WonderTANG! board versions 1.01c, 1.02d and 2.0b.

This branch also modifies the state machine of the signal mux to align it with the behavior of the original tnCart RTL state machine, as the state machine of @buppu3 TangCartMSX for the tnCart board misses a state. With this change, the V9968 RTL on the WonterTANG! works too on other MSX machines that failed to run the original signal mux state machine code for the TangCartMSX on the tnCart board.

Flashing instructions

Note

You will need to use openFPGALoader >= v0.10.0.

WonderTANG 2.0b

• Flash the bitstream tangnano20k_vdp_cartridge_wt200b.fs into the Tang Nano 20k used in your WonderTANG board

  cd RTL/tangnano20k_vdp_cartridge_rev2_step1
  openFPGALoader -f -b tangnano20k --external-flash impl/pnr/tangnano20k_vdp_cartridge_wt200b.fs

WonderTANG 1.02d

• Flash the bitstream tangnano20k_vdp_cartridge_wt102d.fs into the Tang Nano 20k used in your WonderTANG board

  cd RTL/tangnano20k_vdp_cartridge_rev2_step1
  openFPGALoader -f -b tangnano20k --external-flash impl/pnr/tangnano20k_vdp_cartridge_wt102d.fs

WonderTANG 1.01c

• Flash the bitstream tangnano20k_vdp_cartridge_wt101c.fs into the Tang Nano 20k used in your WonderTANG board

  cd RTL/tangnano20k_vdp_cartridge_rev2_step1
  openFPGALoader -f -b tangnano20k --external-flash impl/pnr/tangnano20k_vdp_cartridge_wt101c.fs

How to run the DEVCON demo

Note

When the V9968 RTL is flashed to the WonderTANG! the cartridge acts just as a V9968 VDP without any other WonderTANG! original features enabled, so you cannot use the RAM mapper, SD card, MegaRAM SCC, FM or Sega VDP.

The video output of the V9968 VDP comes out of the HDMI connector of the Tang Nano 20K in the WonderTANG! cartridge, not the MSX video connector.

• Copy the following files to a Nextor bootable mass storage unit (floppy or cartridge) all on the same directory:

  • DEVCON.COM
  • BG.SC5
  • FONT.BIN
  • USA.SC5

• Boot your MSX with the Nextor bootable mass storage unit

• Launch DEVCON.COM

  A> DEVCON.COM
  

• Once the demo starts, use the Down Arrow key to cycle along the different phases of the demo.

  When reaching the end of the demo, the MSX will hang.