Family Basic is an add-on for the Japanese Family Computer, or
Famicom
(Japanese version of the NES), consisting of an
attachable keyboard, and a cartridge containing the BASIC
programming language, developed by Nintendo in collaboration
with Sharp and Hudson (Family Basic identifies itself as
NS-HUBASIC at start-up).
Maybe having BASIC and a keyboard entitles the Famicom to its
name of
Family Computer
?
While language limitations, and very limited memory (2k or 4k, including program listing and data) make Famibe poorly suited for writing, say, a text adventure (as one might normally be inclined to do with a BASIC programming environment), it compensates with the ability to access the Famicom’s graphics hardware to edit and display tiled background graphics, and control animated sprites, which are moved in a separate process from program logic (if the program ends, the sprites can actually keep moving!). Playing sound, however, blocks program logic until it’s done playing (but supports up to three voices).
Instead of typing some unmemorable control-key combination, there is a dedicated STOP key, above the RETURN key, for terminating a running program.
If you want to re-run or enter a modification of a line you’ve already entered, you can simply use the cursor keys to return to that line, make whatever modifications, and hit the RETURN key again. You do not need to return the cursor to the end of the line first; simply press RETURN anywhere on the line to enter it.
Typing overwrites other characters that are present on the line.
To create new space to insert characters, use the
INS key. Note
that, like the Commodore 64, the INS key does not toggle between
an
insert
and an
overwrite
mode, but inserts a single space
on each keypress.
If, when you type, you’re seeing weird Japanese characters instead of normal ASCII characters, try hitting the KANA key. There’s no indicator, and the key doesn’t physically lock down, but the KANA key is a mode-locking key that toggles between ASCII and Japanese katakana characters. While in katakana mode, the GRPH key may also be used together with the top row of keys (only) to generate certain box-drawing characters that may be used in program listings to draw boxes out of characters. Aside from toggling the KANA key, you can also type CTR+W to enter ASCII mode (CTR+V enters kana mode).
If, on the other hand, the whole screen looks full of garbled images, try typing CTR+D, which restores the default character set for the screen, turns off sprite display, and restores the default color palette.
In general, if the screen seems to be in an abnormal state (garbled screen, weird colors, cursor not showing/not responding to input, character sprites displayed), try (1) pressing the STOP key, (2) typing CTR+D, and then (3) holding SHIFT while typing the CLR/HOME key.
When typing over existing on-screen text, CTR+E or CTR+Z may be useful: CTR+E erases from the cursor to end-of-line, CTR+Z erases to end-of-screen.
Integer BASIC. Family Basic is an integer BASIC - all numeric variables are calculated using 16-bit integer math. No floating point/decimal support, and any fractional portion of the result of a division, is discarded.
Two-char significance. As with many other implementations of BASIC for home computers, variable names in Famibe are only distinguished by the first two characters of their name. Additional characters may be used, but only the first two actually identify the variable.
NEXT only branches for the current innermost loop.
This is probably the most cumbersome point for porting BASIC
programs from other systems: the NEXT keyword does not
accept an optional index variable after it - only NEXT
by itself may be used, not (e.g.) NEXT J. It may therefore be
necessary in some cases to rewrite inner loops as explicit increment
& GOTO/IF combinations.
Strings limited to 31 chars! String values - whether in
literal form or created via concatenation, may not exceed 31
characters. The largest impact of this, especially when porting
other BASIC programs, is that some PRINT statements with a
single string argument may need to have that argument broken up
into multiple strings with a semicolon separator:
PRINT "HELLO "; "WORLD"
Hexadecimal support. Hexadecimal numeric values may be specified via the format &HXX.
THEN encompasses colon-separated statements. As with
Microsoft-based BASICs, but unlike, say, Woz’s Integer BASIC,
the THEN keyword will include all the rest of the line,
including colon-separated statements, as the
conditionally-executed body of the IF statement.
Bitwise/logical operators. Since some BASIC
implementations lack them, it’s useful to note that Famibe
supports bitwise/logical operators AND, OR,
NOT, and XOR.
Machine code calls. This BASIC is capable of exceeding
its own considerable limitations with a CALL command.
No lowercase characters.
Save/load programs. You can save a single program to an AA battery-backed memory (but be careful not to jostle the cartridge while flipping the backup switch!), or you can save the program listing as an audio signal to a mono cassette recorder.
Contrary to some people’s claims, a proprietary Nintendo Data
Recorder cassette deck is not required, and early versions of
the manual note that any monaural cassette deck (such as a
Sharp QT-10
) may be used for the purpose.
Also contrary to some claims, the Famicom Disk System may not be used to save or load programs with Family Basic. Both the Famicom Disk System and the Family Basic cartridge occupy the cartridge slot in order to function, and Famicom Disk System disks also lack a filesystem for storing multiple files, and lack random-access capabilities (because of the way the data is stored as a single spiral).
Save/load data from cartridges! A handful of games supported creating user levels and saving them to tape using the Family Basic interface to the cassette recorder. Excitebike, Wrecking Crew, and Loderunner are among the games to support this feature.