at42qt1070 ATMEL Corporation, at42qt1070 Datasheet - Page 21

• Manufacturer Part Number: at42qt1070
• Description: Qtouch 7-channel Sensor Ic
• Manufacturer: ATMEL Corporation

5.8
5.9
5.10
9596A–AT42–10/10
Address 32 – 38: Negative Threshold (NTHR)
Address 39 – 45: Averaging Factor/Adjacent Key Suppression (AVE/AKS)
Address 46 – 52: Detection Integrator (DI)
Table 5-8.
Table 5-9.
Table 5-10.
NTHR Keys 0 – 6: these 8-bit values set the threshold value for each key to register a detection.
Default: 20 counts
Note:
AVE 0 – 5: The Averaging Factor (AVE) is the number of pulses which are added together and
averaged to get the final signal value for that channel.
For example, if AVE = 8 then 8 ADC samples are taken and added together. The result is
divided by the original number of pulses (8). If sixteen pulses are used then the result is divided
by sixteen.
This provides a better signal-to-noise ratio but requires longer acquire times. Values for AVE are
restricted internally to 1, 2, 4, 8, 16 or 32.
Default: 8 (In standalone mode key 0 is 16)
AKS 0 – 1: these bits control which keys are included in an AKS group. There can be up to three
groups, each containing any number of keys (up to the maximum allowed for the mode).
Each key can have a value between 0 and 3, which assigns it to an AKS group of that number. A
key may only go into detect when it has the largest signal change of any key in its group. A value
of 0 means the key is not in any AKS group.
Default: 0x01
DETECTION INTEGRATOR: addresses 46 – 52 allow the DI level to be set for each key. This
8-bit value controls the number of consecutive measurements that must be confirmed as having
passed the key threshold before that key is registered as being in detect. The minimum value for
the DI filter is 2. Settings of 0 and 1 for the DI also default to 2 because a minimum of two
consecutive measurements must be confirmed.
Default: 4
Address
Address
Address
32 – 38
39 – 45
46 – 52
Do not use a setting of 0 as this causes a key to go into detection when its signal is
equal to its reference.
NTHR
AVE/AKS
Detection Integrator
AVE5
b7
b7
b7
AVE4
b6
b6
b6
NEGATIVE THRESHOLD FOR KEYS 0 – 6
AVE3
b5
b5
b5
DETECTION INTEGRATOR
AVE2
b4
b4
b4
AVE1
b3
b3
b3
AVE0
b2
b2
b2
AT42QT1070
AKS1
b1
b1
b1
AKS0
b0
b0
b0
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