Rainbow Electronics MAX11042 User Manual
Page 13
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.
MAX11041/MAX11042
Wired Remote Controllers
___________________________________________________________________________________
13
Figure 9. Jack Insertion Detection
➂
➁
➀
➃
KEY TYPE
JACK
REMOVED
JACK
DETECTED
FALSE
KEYS
TIME
TIME
V
INT
1. JACK INSERTION DETECTED AND ENTERED IN FIFO.
2. JACK REMOVAL DETECTED AND ENTERED IN FIFO.
3. JACK INSERTION DETECTED AND ENTERED IN FIFO.
4. FIFO IS READ UNTIL EMPTY (
INT GOES HIGH).
THE LAST READ BEFORE THE EMPTY FIFO IS REACHED
IS THE FINAL STATE OF THE JACK DETECTION.