MPR121QR2 Freescale Semiconductor, MPR121QR2 Datasheet - Page 18

• Manufacturer Part Number: MPR121QR2
• Description: IC CTLR TOUCH SENSOR 20-QFN
• Manufacturer: Freescale Semiconductor
• Type: Capacitive, Proximity Sensorr

Specifications of MPR121QR2

• Number Of Inputs/keys: 12 Key
• Data Interface: I²C, Serial
• Voltage - Supply: 1.71 V ~ 3.6 V
• Current - Supply: 29µA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-UQFN, 20-µQFN
• Output Type: Logic
• Interface: I²C
• Input Type: Logic
• Supply Voltage: 2.5 V to 3.6 V
• Dimensions: 3 mm L x 3 mm W x 0.65 mm H
• Temperature Range: - 40 C to + 85 C
• Termination Style: SMD/SMT
• Supply Current: 29µA
• Ic Interface Type: I2C
• Supply Voltage Range: 1.71V To 3.6V
• Sensor Case Style: QFN
• No. Of Pins: 20
• Operating Temperature Range: -40°C To +85°C
• Interface Type: I2C
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: MPR121QR2; MPR121QR2TR

MPR121
18
AUTO-CONFIG LSL REGISTER
The last setting required to set up the auto-configuration system is the AUTO e Register.
AUTO-CONFIG CONTROL REGISTER
This register represents the target level for the auto-configuration. The value can be calculated by:
For a 1.8 V system, this value is 140 or 0x8C.
This register represents the lower limit for the auto-configuration. The value can be calculated by:
For a 1.8 V system, this value is 101 or 0x65.
Table 16. AUTO-CONFIG LSL Register Field Descriptions
Table 15. AUTO-CONFIG Target Level Register Field Descriptions
Field
LSL
Reset:
Reset:
7:0
Field
7:0
TL
W
W
R
R
7
0
7
0
T
AFES
Lower Limit – The Lower Limit for the auto-configuration baseline search is set to this value.
00000000 – Lower Limit set to 0
00000001 – Lower Limit set to 1
~
11111111 – Lower Limit set to 255
T
arg
arg
= Unimplemented
= Unimplemented
Target Level – The Target Level for the auto-configuration baseline search is set to
this value.
00000000 – Target Level set to 0
00000001 – Target Level set to 1
~
11111111 – Target Level set to 255
et
et
=
6
0
6
0
Figure 15. AUTO-CONFIG Control Register
=
Figure 14. AUTO-CONFIG LSL Register
V
------------------------- - 256 0.65
V DD 0.7
------------------------- - 256 0.9
DD
V
V
DD
DD
–
–
0.7
5
0
5
0
⋅
RETRY
⋅
⋅
⋅
4
0
4
0
LSL
Description
Description
3
0
3
0
BVA
90% of USL
65% of USL
2
0
2
0
ARE
1
0
1
0
Freescale Semiconductor
ACE
0
0
0
0
Sensors