Pioneer ER-101
This page was last modified 17:03, 11 December 2018 by Rderooy. Based on work by Manuel and Gdx and others.



The ER-101 Expansion Processor unit allows you to connect a Laser Vision Video Disc player to a common MSX almost as if you had a Pioneer Palcom. It is aimed at the Japanese market.

The unit also provides the Pioneer P-BASIC extensions needed to control a laserdisc player from BASIC.


Pioneer Expansion Processor ER-101
Pioneer ER-101, Expansion Processor back connectors
Pioneer AWX-302 Slot Connector


The ER-101 has a TMS9928/A VDP with 16kB of VRAM, 2kB RAM and a 8kB ROM that contains P-BASIC. This expansion can only be used with MSX computers which have at least 32kB RAM. Note that the P-BASIC ROM, even when disabled, can be a source of incompatibility.

The included AWX-302 Slot Connector cartridge is just a buffered "cartridge slot to expansion bus" adapter. The unit can probably be directly connected on an MSX expansion bus (primary slot) if the cable is not too long.

I/O ports to access the external VDP are the same as usual: 0x98 and 0x99 (write only). See service manual page 16.

Bit 4 of the PPI (I/O port 0xAA) is called the MTON register (This is normally used for cassette motor control.). There is memory-mapped I/O on 7FFFh, called the VCON register. The sound control circuit does ON or OFF of muting against external stereo sound input. By writing the 7th bit of VCON register (refer to table 4-4 on p.19 of the service manual) and output of 4th bit of MTON register, it generates muting signal for L/R channel (LMUTE, RMUTE). On muting R channel, L->H operation against LMUTE is required because leading edge of LMUTE is used for latch.

Supported computers:
- Canon V-10, V-20
- Fujitsu FM-X
- Hitachi MB-H1
- Mitsubishi ML-F110, ML-F120, ML-F120D - National CF-2000
- Sanyo MPC-5, PHC-30
- Toshiba HX-10S/SA, HX-10D, HX-10DP, HX-10DPN
- Victor HC-5, HC-6
- Yamaha YIS-303, YIS-503, CX-5, CX-5F

Unsupported computers:
- General PCT-50
- Mitsubishi ML-8000
- National CF-3000
- Sanyo MPC-10, MPC-11
- Sony HB-55, HB-75


  • Composite input/output (RCA)
  • Analog stereo sound input/output (RCA)
  • Analog mono sound input (RCA)
  • RF Mod output (5 pin DIN, the optional RF converter PX-RF7 is required to connect to a TV)
  • 1 LD control output for the LD-7000 or compatible (8 pins DIN)
  • 1 LD control output for the LD-1000 (mini jack)
  • 1 cartridge slot
  • 50-pin IDC connector, to connect the unit to the Slot Connector cartridge.
  • AC 100V power plug (for the monitor)

Minimum System Requirements

  • Japanese MSX1 computer with 32kB RAM
  • One free cartridge slot (Primary slot) for the Slot Connector adapter, which connects to the front of the ER-101