Category:Toshiba HX-21
This page was last modified 15:58, 18 January 2021 by Mars2000you.

Contents

Description

The HX-21 is an improved version of the HX-20 computer as it comes with a RGB output connector. It is an intermediate machine between the HX-20 and the HX-22.

The following models exist:

Product Region Keyboard Video and audio out Other
HX-21 JP QWERTY/JIS RF, composite video and stereo audio, RGB RP13A Optional RS-232C module
HX-21F FR QWERTY with accent key only RGB SCART


Although it's a MSX1 computer, the Japanese model can use a part of the MSX memory to create a Memory Disk (feature generally reserved for MSX2 and higher computers).

As option, a RS-232C interface with switch can be added on the Japanese machine. It is not possible on the version released in France.

Brand Toshiba
Type HX-21 / HX-21F
Year 1984-10-16 (Japan)
1985 (France)
Region HX-21: Japan
HX-21F: France
Original price JP: ¥79,800
RAM 64kB in slot 3-0 (HX-21) or probably split between slots 0 and 3-0 (HX-21F)
VRAM 16kB
Media MSX cartridges
Video Texas Instruments TMS9928A
Audio PSG (AY-3-8910A)
Chipset Toshiba TCX-1010 in HX-21, Toshiba TCX-1012 in HX-21F
Keyboard layout QWERTY/JIS
Extras firmware (Japanese Word Processor - Kanji-Kun v.2.0 or English Word Processor), (only Japanese version)MemoryDisk BASIC, Printer BASIC, stereo PSG sound, (optional) RS-232C interface + switch + RS-232C BASIC
Emulation ROMs dumped and emulated for the HX-21 version. ROM dumps needed for the HX-21F version. See this thread for details

Pictures

Check also the pages about the different models!

Toshiba HX-21
Toshiba HX-21 back
Toshiba HX-21 right side
Toshiba HX-21F
Toshiba HX-21 inside
Toshiba HX-21F inside
Toshiba HX-21F back
Toshiba HX-21F right side

Specifications

The HX-21 is a MSX1 with 2 cartridge slots (one at the top, one at the back) and a a Z80A from Sharp (LH-0080A).

The 2 joystick ports are located on the right side of the computer, as well as the data recorder connector.

In the HX-21F, the 64kB RAM is probably split in half between the slots 0 and 3-0, a configuration that can cause poorly written software to crash. Also, with this layout, the POKE-1,(15-PEEK(-1)\16)*17 trick to workaround buggy software that does not handle subslots properly will not work on this machine.

Slot Map on HX-21

Slot 0 Slot 1 Slot 2 Slot 3-0 Slot 3-1 Slot 3-2 Slot 3-3
Page C000h~FFFFh Cartridge
Slot 1
Cartridge
Slot 2
64kB
RAM
Mirror
Page 8000h~BFFFh Firmware
Page 4000h~7FFFh Main-ROM
Page 0000h~3FFFh Mirror
  • The Firmware ROM is a 32kB ROM - 4000h-BFFFh, which is mirrored (4000h-7FFFh is mirrored to C000h-FFFFh and 8000h-BFFFh is mirrored to 0000h-3FFFh)

Slot Map on HX-21F

Help needed
The below slot-map is an assumption, it needs to be checked on a real machine.
Slot 0 Slot 1 Slot 2 Slot 3-0 Slot 3-1 Slot 3-2 Slot 3-3
Page C000h~FFFFh Upper
32kB RAM
Cartridge
Slot 1
Cartridge
Slot 2
Mirror
Page 8000h~BFFFh Firmware
Page 4000h~7FFFh Main-ROM Lower
32kB RAM
Page 0000h~3FFFh Mirror
  • The Firmware ROM is a 32kB ROM - 4000h-BFFFh, which is mirrored (4000h-7FFFh is mirrored to C000h-FFFFh and 8000h-BFFFh is mirrored to 0000h-3FFFh)

Connections

Pages in category "Toshiba HX-21"

The following 2 pages are in this category, out of 2 total.

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