SX8650 Datasheet, PDF (36/56 Pages) Semtech Corporation – World’s Lowest Power & Smallest Footprint 4-wire Resistive Touchscreen Controller with 15kV ESD

SX8650
World’s Lowest Power & Smallest Footprint 4-wire
Resistive Touchscreen Controller with 15kV ESD
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
4.8. Host Control Writing
The host control writing allows the host to change SX8650 settings. The control data goes from the host towards the
SX8650 and may be read back for verification.
register
I2CRegCtrl0
I2CRegCtrl1
bits default
description
Set rate in coordinates per sec (cps) (± 20%)
If RATE equals zero then Manual mode.
if RATE is larger than zero then Automatic mode
7:4 0000 RATE
0000: Timer disabled -Manual mode 1000: 300 cps
0001: 10 cps
1001: 400 cps
0010: 20 cps
1010: 500 cps
0011: 40 cps
1011: 1k cps
0100: 60 cps
1100: 2k cps
0101: 80 cps
1101: 3k cps
0110: 100 cps
1110: 4k cps
0111: 200 cps
1111: 5k cps
Settling time (± 10%): The channel will be biased for a time of POWDLY
before each channel conversion
3:0 0000 POWDLY
0000: Immediate (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: 0.14 ms
1001: 0.28 ms
1010: 0.57 ms
1011: 1.14 ms
1100: 2.27 ms
1101: 4.55 ms
1110: 9.09 ms
1111: 18.19 ms
7:6
00 AUXAQC
00: AUX is used as an analog input
01: On rising AUX edge, wait
POWDLY and start acquisition
10: On falling AUX edge, wait
POWDLY and start acquisition
11: On rising and falling AUX
edges, wait POWDLY and start
acquisition
The AUX trigger requires the manual mode.
Enable conditional interrupts
5
1 CONDIRQ
0: interrupt always generated at end of conversion cycle. If no pen is
detected the data is set to ‘invalid qualified’.
1: interrupt generated when pen detect is successful
4
0 reserved
3:2
00 RPDNT
Select the Pen Detect Resistor
00: 100 KOhm
01: 200 KOhm
10: 50 KOhm
11: 25 KOhm
1:0
00 FILT
Digital filter control
00: Disable
01: 3 sample averaging
10: 5 sample averaging
11: 7 sample acquisition, sort, average 3 middle samples
Table 9. I2C registers
ACS Revision V2.15/October 2009
©2009 Semtech Corp.
Page 35
www.semtech.com