according to the diagram below. See chapter 4 for more info on potentiometers
usage.
The key contacts must use one common buss
bar (with GND), or logic IC may control BBSP
inputs. 0V at an input means “key pressed”,
+5V at input or left open means “key
released”. Keyboard should be connected to
two 16-pin headers according to the diagram
below.
Works best with 2 IDC plugs and 16-wire ribbon cable, ordered separately.
Each black connector holds 16 inputs for keyboard
switches. The pin numbering within one connector is
shown here. Notice orientation of the keying slot. This
pinout is valid for every 16-pin connector in every board.
7.4
BBS-1K common ground keyboard scanner
This board is mainly used as a scanner of 5-octave keyboard. It has 64 contact
inputs, and daisy-chain input, so you can use 2 such boards connected to 1 MBBS
input. All 4 connectors for ribbon cable and the pinout are the same as used in
BBSP - see above. Each black connector covers 16 keys. BBS-1K must be connected
towards the MBBS with 4-way connector indicated "OUT". The connector marked
"IN" is for the purpose of adding
next optional scanner. There can be
only 2 keys scanners (BBS-1K, BBSP,
DMS-2K, PDS, LITSW) in one chain.
If third keyboard scanner is chained,
it will work like paralleled inputs of
2nd keyboard in the chain.
7.5
BBS24 little scanner for contacts & pots
This one is especially suited for the bass/chord part of MIDI accordions. It works
with 24 switches, and 3 analog sources like pots, or voltages e.g. from pressure
sensor. If split is set in the middle (chapter 5.5.) 12 inputs can be assigned to
basses, and 12 to chord contacts in accordion and play in different channels. The
board is small enough to put it inside bass/chord part of an accordion. Unlike other
22
