How do the keyboards on Subor Famiclones work?

Started by Omarinco, November 20, 2020, 04:13:33 pm

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Omarinco

Title says it all. Does it work in the same way as Family BASIC or...?
I'm quite curious as to these specific Famiclones.
I'm also curious as to Family BASIC's keyboard.
Sorry if this is too much of a newbie question, I'm just very curious. Thanks.

fcgamer

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What do you want to know? If you can understand it, there are good descriptions of it on the Nesdev wiki. It's read serially by the game using four pins (for 4 rows of the key layout). It's called multiplexing, and makes it possible to go around the fact that there are not one pin for every key. It basically works like this: The Famicom game sends a signal to the keyboard that it want to know all keys that are pressed in a specific row, and the keyboard sends this data for each key on the row, one by one, in the corresponding pin.
Famicom controllers also uses multiplexing (unlike Sega controllers), but uses only one pin for all 8 buttons (microphone data not included, it's a separate device), and sends them all every time the game requests them.

I think there are like two or three different types of Famiclone keyboards, none of which works like the Family Keyboard, and are thus incompatible with Family BASIC.