User's Manual

T-0000-0004-V2.1: Using Mozart II
T-0000-0004-V2.1: Using Mozart II Page: 11 / 24
19; SELECT DIG O Signal to control an audio
switch when external analog
devices are required
28; EXT_C DIG O Extender Clock
30; EXT_S DIG O Extender Strobe
12; KP_RET DIG I Keyboard Keypress Return
40; KP_W0 DIG I Rotary Encoder Signal 0
39; KP_W1 DIG I Rotary Encoder Signal 1
39; MMI_IR DIG I Infrared Demodulated data
input
7 Dealing with Keypad and Rotary
7.1 HARDWARE CONSIDERATIONS
The module features support for a matrix keyboard and a rotary encoder. The matrix is 16x1 and does
not support simultaneous presses; however both long and short presses can be detected when a
matrix configuration is used. All switches used in the matrix must be electrically independent – this is
important if a rotary encoder with integrated pushbutton is to be used, since some models have
common pins between the rotary encoder itself and the pushbutton. The integrated pushbutton is just
treated as part of the general button matrix.
The rotary encoders supported by the module have two switches with a common connection. The two
switches should provide signals in quadrature, the order of the rising edges provide the rotation
direction and the number of edges the number of “turning steps”. The signals look like this:
A typical application schematic would be as follows. Note that the RC values might need fine-tuning
according to the type of encoder used: