MAX11041_10 Datasheet, PDF (13/17 Pages) Maxim Integrated Products – Wired Remote Controller

Wired Remote Controller
Simultaneous Keypress Detection
Certain applications require the detection of
simultaneous keypresses, such as <SHIFT+KEY> and
<FUNCTION+KEY> combinations. This is done in
software. For instance, the µP detects the SHIFT key is
being pressed. When the µP detects an additional key-
press instead of a key release, it knows the corre-
sponding code is a result of two resistors
in parallel.
Order of Keypress Detection
Some applications require detection of the specific
sequence of keys in software by looking for unique key
presses within 32 ticks (1s). If the duration between
keypresses exceeds the allowed time, assume the key-
press is in error and return to the previous known state.
Power-Up Jack Detect and Keypress
Example
Figure 10 illustrates the FIFO entries during a typical
sequence of events.
Layout, Grounding, and Bypassing
Position R_SENSE and C_SENSE as close to the device as
possible. Bypass V_DD with a 0.1µF capacitor to GND as
close to the device as possible. Connect GND to a
quiet analog ground plane. Route digital lines away
from SENSE and FORCE.
FORCE
WIRED REMOTE CONTROLLER
R_SW0
R_SW1
R_SW30
HOLD SWITCH
R_JACK
Figure 10. Software Implemented Hold-Switch Configuration
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