STMPE321 ST Microelectronics, STMPE321 Datasheet - Page 29

• Manufacturer Part Number: STMPE321
• Description: 3-channel capacitive touch key controller
• Manufacturer: ST Microelectronics

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STMPE321
FILTER_PERIOD
Address:
Type:
Reset:
Description:
FILTER_THRESHOLD
Address:
Type:
Reset:
Description:
REFERENCE_DELAY
Address:
Type:
Reset:
Description:
RESERVED
7
7
7
[7:0] FILTER_COUNT:
[7:0] FILTER_THRESHOLD:
[6:0] REFERENCE_DELAY:
[7] RESERVED
6
6
6
0x28
R/W
0x00
Filter period.
Additional filter to stabilize touch output in AFS mode.
AFS touch output is monitored for Filter Count [7:0] times every integration time. For each time
a "touch status" is detected, an internal "Filter Counter" is incremented once. This counter
value is then compared with Filter Threshold (register 0x3E)
0x29
R/W
0x00
Filter threshold.
An internal "Filter Counter" is compared with Filter Threshold [7:0] to determine if a valid touch
has occurred.
0x2A
R/W
0x00
Shifting of capacitive sensor dynamic range. The capacitance value set into this
register is in effect, equivalent to capacitor connected to the A_Ref pin.
Valid range = 0-127
Each step represents capacitance value of 0.05 pF
Warm reset is required after this value is updated
5
5
5
4
4
4
Doc ID 15791 Rev 1
FILTER_THRESHOLD
FILTER_COUNT
3
3
3
REFERENCE_DELAY
2
2
2
Capacitive touch module registers
1
1
1
Reference delay
Filter threshold
Filter period
0
0
0
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