sx8675iwltrt Semtech Corporation, sx8675iwltrt Datasheet - Page 49

• Manufacturer Part Number: sx8675iwltrt
• Description: Haptics Enabled Multitouch 4/5-wire Resistive Touchscreen Controller With Proximity Sensing
• Manufacturer: Semtech Corporation

ADVANCED COMMUNICATIONS & SENSING
Bits
Bits
Rev 1 – 25
7:4
3:0
7:5
3:2
1:0
4
Variable
TOUCHRATE
POWDLY
Variable
Reserved
TSTYPE
RPNDT
FILT
th
July 2011
Default
Default
0000
0000
001
00
00
0
Table 13 : RegTouch0 (Addr 0x00)
Table 14 : RegTouch1 (Addr 0x01)
Description
Defines the touch coordinates acquisition rate:
0000 : OFF.
0001 : 10 cps
0010 : 20 cps
0011 : 40 cps
0100 : 60 cps
0101 : 80 cps
0110 : 100 cps
0111 : 200 cps
1000 : 300 cps
1001 : 400 cps
1010 : 500 cps
1011 : 1 kcps
1100 : 2 kcps
1101 : 3 kcps
1110 : 4 kcps
1111 : 5 kcps
Values above assume typical FOSCL, else vary accordingly.
Defines the bias settling time for each channel’s first conversion:
0000 : 0.5 us
0001 : 1.1 us
0010 : 2.2 us
0011 : 4.4 us
0100 : 8.9 us
0101 : 17.8 us
0110 : 35.5 us
0111 : 71.0 us
1000 : 142 us
1001 : 284 us
1010 : 768 us
1011 : 1.14 ms
1100 : 2.27 ms
1101 : 4.75 ms
1110 : 9.09 ms
1111 : 18.19 ms
Values above assume typical FOSCH, else vary accordingly.
Description
Defines the type of touchscreen:
0 : 4-wire
1 : 5-wire
Defines the pen detection circuit’s pull-up resistor value:
00 : 114 kOhms
01 : 228 kOhms
10 : 57 kOhms
11 : 28 kOhms
Defines the channel filtering algorithm:
00 : OFF (Nfilt = 1)
01 : 3 sample averaging (Nfilt = 3)
10 : 5 sample averaging (Nfilt = 5)
11 : 3 sample averaging after removal of extreme values (Nfilt = 7)
Resistive Touchscreen Controller with Proximity Sensing
49
SX8674/SX8675/SX8676
Haptics Enabled Multitouch 4/5-Wire
www.semtech.com