at42qt1481 ATMEL Corporation, at42qt1481 Datasheet - Page 54

• Manufacturer Part Number: at42qt1481
• Description: 48-key Qmatrix Ic
• Manufacturer: ATMEL Corporation

Table 5-4.
Byte
144
192
240
288
336
337
338
340
341
342
48
96
0
Neg threshold
Pos Threshold
Neg Drift Comp
Pos Drift Comp
Normal DI Limit
Fast DI Limit
Neg recal delay
Pos recal delay
Burst Length
AKS
Cal.Freq.Offset 1
Cal.Freq.Offset 2
Neg Hysteresis
Mains Sync
Sleep Drift Comp
Threshold Mult
Dwell Time
Serial rate
Lower Signal Limit
Restart Int. Burst
FMEA KGTT
STATUS Output
Awake Time
Drift Hold Time
Scope Sync
Parameter
Setups Block
NTHR
PTHR
NDRIFT
PDRIFT
NDIL
FDIL
NRD
PRD
BL
AKS
CFO_1
CFO_2
NHYST
MSYNC
SDC
THRM
DWELL
SR
LSL
RIB
KGTT
STS
AWAKE
DHT
SSYNC
Symbol
Bytes
48
48
48
48
48
48
48
1
1
2
1
1
1
NDRIFT = 0 – 15
PDRIFT = 0 – 15
DWELL = 0 – 15
NTHR = 0 – 15
NHYST = 0 – 3
LSL = 0 – 2047
PTHR = 0 – 15
KGTT = 0 – 15
Valid Range
MSYNC = 0, 1
NDIL = 0 – 15
FDIL = 0 – 15
THRM = 0 – 3
PRD = 0 – 15
SDC = 0 – 7
AKS = 0, 1
SR = 0 – 4
BL = 0 – 3
RIB = 0, 1
0 – 254
0 – 255
0 – 255
0 – 255
0 – 255
0 – 15
0 – 15
Bits
11
4
4
4
4
4
4
8
4
2
1
8
8
2
1
3
2
4
4
1
4
8
4
4
8
6 (X line)
Scope
device
device
Key
48
48
48
48
48
48
48
48
48
48
1
1
1
1
1
1
1
1
1
1
1
1
Default
Value Description
0x20
100
10
10
20
15
11
6
2
2
5
6
2
0
0
0
1
0
0
0
1
0
0
7
0
Lower nibble = Neg Threshold - take operand and add 4 to get value
Upper nibble = Pos Threshold - take operand and add 4 to get value
Lower nibble = Neg Drift comp - Via LUT
Upper nibble = Pos Drift comp - Via LUT
Lower nibble = Normal DI Limit, values same as operand (0 = disabled burst)
Upper nibble = Fast DI Limit, values same as operand (0 is invalid; do not
use)
Range is in 0.5 sec increments; 0 = infinite; default = 10s (operand = 20)
Range is {infinite, 0.5 – 127s}; 255 is illegal to use
Lower nibble = PRD, via LUT, default = 6 (1 second)
Bits 5, 4: = BL, via LUT, default = 48 (setting = 2)
Bit 6 = AKS, 1 - enabled
Value is the signal offset
Value is the signal offset
Bits 1,0 = Neg hysteresis, all keys; default = 12.5%
Bits 5 = Mains sync, negative edge, 1 = enabled; default = 0 (off)
Bits 4 – 2 = Sleep Drift Compensation, 0 = sleep disabled (default)
Bits 7, 6 = Threshold Multiplier; default = 0 (x1)
Lower nibble = Dwell time, 15 values via LUT, default = 1 (188 ns)
Upper nibble = serial rate via LUT - 9600, 19.2k, 38.4k, 57.6k, 115.2k
(UART)
Bits 10 – 0 = Lower limit of acceptable signal; below this value, QT1481
declares an error. The low order byte should be sent first.
Bit 11 = Restart Interrupted Burst, 1 = enabled
Bits 15 – 12 = KGTT Default = 7 (32 counts)
Defines the STATUS pin behavior; see
Lower nibble = Awake Time, default = 15 (25.4s)
Upper nibble = Drift Hold Time, default = 11 (9s)
Each bit enables the scope sync output for the burst one one X line.
Bit n: 1 = Scope sync enabled for burst on Xn.
Table 5-5 on page 55
Page
39
40
40
42
43
43
44
44
52
52
46
46
47
40
46
48
48
47
48
49
50
50
45