dipswitches keys and charsets - cayce-msx/msxpp-quick-ref GitHub Wiki

• SX1 & related: LEDs are in reverse order of DIP switches. There's one extra (8 vs. 9) to show clock speed (3 states).
• SX2 & related: there is only one LED ("main LED") which flashes on disk access ("LED 1" below). On the SX2, it's visible through the transparent pane, located left of the "SX|2" logo.

Bold = standard setting

All but RAM mapper size & microSD can be changed at runtime using keyboard.

Note: dipswitch 7 is shared; EP-BIOS 1 always selects 2048kB RAM and EP-BIOS 2 always selects 4096kB RAM. This can be overridden by holding right-CTRL during boot; that will enable 4096kB RAM even when dipswitch 7 is OFF (thus EPBIOS 1 is loaded).

On SX1 & related, LEDs 2-9 show new volume briefly after changes, as a volume bar. Note: the volume bar goes right to left (volume 2 lights LEDs 8&9, etc).

*) pressing Shift-Scroll Lock, to flip through slot-2 modes on my USB keyboard (with Adder USB-to-PS/2 converter) actually enables the Scroll Lock LED! This is a bit awkward, because MSX++ signals "CMT mode", i.e., tape input enabled, with that LED. So in this case, the LED is on, but CMT mode is off. Not sure if this works the same on all keyboards.

**) On OCM-PLD 3.9.0 and higher, to force loading of EPBIOS even though there is an SDBIOS on the inserted μSD card: first hard reset the machine by holding the reset button longer than a second. Then wait until the MicroSD slot R/W indicator (SX1: leftmost, SX2: main LED) starts flashing, and click the reset button again. (A regular short click will do.) The required timing is pretty precise, but it does work.

A few keys can be held at startup. This will reconfigure the MSX++. Note: this is supported since version 3.9.2.

These two settings can not be combined; Extra-Mapper is located in Slot0-1.

So, you thought because you can tailor the OCM-PLD firmware to a few keyboard types (BR, ES, FR, IT, US, JP), the MSX keyboard would synchronise with that? Well, at least I did ;)

(With 'synchronising' I mean: BIOS address &H002C would flip from 0 to 1 through 6, and the key matrix would be interpreted as, e.g., International or Spanish / Argentinian.)

Alas, no, the firmware keyboard type only has an effect on how the PS/2 key presses are interpreted. With SETSMART -15 (Set Japanese Keyboard Layout) / SETSMART -16 (Set Non-Japanese Keyboard Layout - which is the default) - or more conveniently with KEYBOARD.COM /J respectively KEYBOARD.COM /N - you can switch between key press translation modes:

• Japanese: make it appear like you're typing on a Japanese keyboard
  • For example, when (on my US-International Ansi104 keyboard) typing shift-2, the keyboard symbol says "@" but a " appears. I press symbol ] and [ appears, etc.
  • this mode is the default (enabled at boot) when flashing a OCM-PLD firmware with JP keyboard
• Non-Japanese Keyboard: use the layout as hardcoded into your OCM-PLD firmware - which can be BR, ES, FR, IT or US

Note that the above is true only when using a Yen or Backslash MainROM BIOS. See Western charset how that changes with the third MainROM type.

More details: see OCM-PLD Pack at

• esemsx3/src/peripheral/eseps2_spec/eseps2_spec_english.txt
• esemsx3/src/peripheral/keymap_work/scan_codes_us_jp.htm
• esemsx3/src/peripheral/keymap_work/scan_codes_set_2.htm

The "Yen" charset is the same as any Japanese MSX contains.

The "Backslash" charset is the same as Yen, but then ¥ replaced by . It helps for more familiar DOS path names - for those that are more accustomed to .

This charset is the default when creating an SDBIOS with make-sdb.bat/make-sdbios.sh, and is part of the standard EPBIOS.

The YENSLASH.COM tool from OCM-PLD msxtools can be used to change Yen to backslash and vice versa, at runtime.

When you load an SD-BIOS with a 'Western' MainROM, these are the characters that can be shown on screen. They are the same as, e.g., the NMS8250.

Taken from openMSX:

<2 rows with characters that could not be copy-pasted>
 !"#$%&'()*+,-./
0123456789:;<=>?
@ABCDEFGHIJKLMNO
PQRSTUVWXYZ[\]^_
`abcdefghijklmno
pqrstuvwxyz{|}~
ÇüéâäàåçêëèïîìÄÅ
ÉæÆôöòûùÿÖÜ¢£¥□□
áíóúñѪº¿□¬□□¡«»
Ãã□□Õõ□□□□□□□□¶§
<4 rows with characters that could not be copy-pasted>

A full screenshot:

Recommended setup:

• KEYBOARD.COM /J: Japanese-106
  • might feel counterintuitive, but works!
• Physical keyboard: ISO105
  • When using a (Dutch) Ansi104 keyboard, you'll not be able to enter the | and \ characters! PS/2 set 2 scancode 61h will be missing.
• OCM-PLD 3.9.1

The results resemble the keymap published by KdL. That keymap is actually an unedited hires scan from the NMS8280 user manual.

I've adapted that keymap for ISO105 keyboards to convey the following information:

• it's only valid in Japanese keyboard mode (KEYBOARD.COM /J)
  • only if you flash the Japanese OCM-PLD firmware build, then that mode will be enabled at boot
  • the US firmware, however (which comes pre-installed with 8bits4ever device), sets the KEYBOARD /N layout at boot
• the `~-key maps to MSX 'SELECT' (which MSX++ also maps from F8)
  • fun fact: SELECT (and thus ` in this mode, with or without SHIFT) clears the command line in COMMAND2.COM v2.4x. (COMMAND-2.44-TNI/history.txt mentions a few line editing key combos, but not this one)
• ` and ~ (and the four symbols as shown on the keymap topleft) must instead be entered using the rightmost \|-key (which is missing on KdLs keymap)
• the leftmost \|-key is the (only) way to enter characters \ and | (and the two symbols as shown on the keymap bottomleft)
  • ⚠️ my SX1 with OCM-PLD 3.9.0 fails on this. It triggers unmapped MSX key r15b7 ("N/A"), not r1b4. I can't find a bugfix description for 3.9.1, so I'm not sure what causes this.
• as you'd expect with Western layout, CODE (F7) is not a lock like caps lock, but rather a modifier like shift and graph (left-alt/F6)
• some of these symbols appear only in BASIC, not in DOS (yes, I made that mistake). Probably related to DOS itself; not the hardware, firmware or configuration.

Note that this setup does not map the DEAD/accents key (r2b5)! A true JP-106 keyboard is required for this (or any other keyboard that generates PS/2 set 2 scancode 51h). So you'll need to use (or memorise) the keymap linked above to enter characters like é and î.

At boot, the non-Japanese keyboard mode is set by default. With a Western MainROM that mode will actually remap keys very awkwardly.

Also, ')' cannot be entered.

Fun fact: the DEAD/accents key is partially mapped in this mode:

• SHIFT+'-' followed by 'a' displays á
• SHIFT+F7+'-' followed by 'a' displays ä
• etc.

So of the full set of accents `´^¨ only ´¨ can be entered (type éë but not èê).

Photo of all key combos. Note that not all 253 characters from the charset are present.

Note that you can 'look up' the special characters: find the wanted character in the 'International key matrix', then type the corresponding key found in the 'Japanese key matrix'. For instance, for '^' that is row 0, bit 6 in the INT matrix (plus SHIFT). The JP matrix row 0, bit 6 reads '&' so that is what you need to type (using SHIFT+7) to get ^ on screen.