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Re: Cycle of Keyboard?

sicklittlemonkey wrote:

Heh. Language is a funny thing.
Wish my Japanese was half as good as your Englisch. ;-)

Anyway, I checked up on the ][  and ][+ keyboard repeats.
Both are wired with 555 timers independent from the system clock.
The ][ repeat rate is 10Hz; the ][+ is 15Hz.

It's interesting how different they are! Fixed-width font table:

Machine          ][        ][+     //e
Keybounce Mask   8 ms(?)   7 ms    ~10 ms
Strobe Duration  10-20 us  ~45 us  20 us(?)
Repeat Delay     0-100?    ?       534-801 ms* (PAL=?)
Repeat Rate      10 Hz     15 Hz   15 Hz* (PAL=12.5?)

* = depends on video timing

Several values remain uncertain:
? = unstated
(?) = implied, but unstated


I suggest that the differences between the ][ and ][+
are not actually characteristic of those particular
models, but just an evolutionary change from early
to later ][/][+ machines.

I say this because the only difference between the
][ and ][+ was the ROMs and the "badge" on the cover.

-michael

Music synthesis for 8-bit Apple II's!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
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