User manual

MCP401X/2X Evaluation Board User’s Guide
DS51546B-page 13 © 2005 Microchip Technology Inc.
TABLE 2-1: DIGITAL POTENTIOMETER EVALUATION BOARD FIRMWARE INCREMENT/DECREMENT COMMANDS
Command Button Sequence
#
Increment/Decrement -
(Low Voltage/High Voltage)
# of
Steps
Saves Wiper
Value in EEPROM
High Voltage on
CS
and U/D pins?
After
Command
Wiper is
Works when
Wiper is “locked”
MCP401x will
INCR/DECR
#1
(Depress)
(5)
#2
(Depress)
(5)
#3
(Release)
#4
(Release)
“locked”
“unlocked”
1 INCR - (Low Voltage) 1
(1)
Yes No — — No Yes INCR (for < 2 sec)— ——
2 INCR - (High Voltage)
(6)
1
(1)
Yes Yes — Yes Yes Yes INCR (for < 2 sec) DECREMENT
(for < 2 sec)
INCR DECR
3 INCR - (High Voltage)
(6)
1
(1)
Yes Yes Yes — Yes Yes INCR (for < 2 sec) DECREMENT
(for < 2 sec)
DECR INCR
4 INCR - (Low Voltage) 64
(2)
Yes No — — No Yes INCR (for > 2 sec) — — —
5 INCR - (High Voltage)
(6)
64
(2)
Yes Yes — Yes Yes Yes INCR (for < 2 sec) DECREMENT
(for > 2 sec)
INCR DECR
6 DECR - (Low Voltage) 1
(3)
Yes No — — No Yes DECR (for < 2 sec) — — —
7 DECR - (High Voltage)
(6)
1
(3)
Yes Yes — Yes Yes Yes DECR (for < 2 sec) INCR (for < 2 sec) DECR INCR
8 DECR - (High Voltage)
(6)
1
(3)
Yes Yes Yes — Yes Yes DECR (for < 2 sec) INCR (for < 2 sec) INCR DECR
9 DECR - (Low Voltage) 64
(4)
Yes No — — No Yes DECR (for > 2 sec)— — —
10 DECR - (High Voltage)
(6)
64
(4)
Yes Yes — Yes Yes Yes DECR (for < 2 sec) INCR (for > 2 sec) DECR INCR
Note 1: Move wiper W towards node A (Increment wiper 1 step).
2: Move wiper W to node A (Increment wiper 64 steps). Forces the wiper setting to “full-scale” (wiper W = node A). 3: Move wiper W towards node B (Decrement wiper 1 step). 4: Move wiper W to node B (Decrement wiper 64 steps). Forces the wiper setting to “zero scale” (wiper W = node B). 5: If there is more than one sequence, the button sequence #1 must continue to be held down while progressing to sequence #2. Example: Command # 2.
requires the INCR button to be depressed. Then, before 2 seconds elapses, the DECR button must be depressed. Next, before 2 seconds elapses, the INCR button must be released. The DECR button can then be released.
6: High-voltage commands require a system voltage (V
DD
) greater than 5.0V to allow the simple charge pump to generate the V
IHH MIN
voltage for the CS pin.