BU21029GUL Datasheet, PDF (14/29 Pages) Rohm – 4-wire Resistive Touch Screen Controller

BU21029GUL
Datasheet
HOST
INT
Turn On
X+ and X-
Drivers
(CF=0x8)
SCAN X
(CF=0xC)
tConv1
BU21029
Detecting
touch
Waiting for Sample and Conversion
scan command
for X coordinate
Read
result of
SCAN X
Turn On
Y+ and Y-
Drivers
(CF=0x9)
SCAN Y
(CF=0xD)
tConv1
Detecting
touch
Waiting for Sample and Conversion
scan command
for Y coordinate
Figure 6. Touch Screen Scan Flow 1 (X and Y scan)
Read
result of
SCAN Y
Detecting
touch
HOST
INT
Turn On
X+ and Y-
Drivers
(CF=0xA)
BU21029
Detecting
touch
SCAN Z
(CF=0xE)
Waiting for
scan command
Read
result of
SCAN Z1
Read
result of
SCAN Z2
tConv2
tConv3
Sample and Conversion Sample and Conversion
for Z1 coordinate
for Z2 coordinate
Detecting
touch
Figure 7. Touch screen scan flow 2 (Z1 and Z2 scan)
tPON
= 710us
tDLY1
= 1.5us
tADC
= 18us
tDLY2
= 1.0us
tTIME_ST_ADC = register (addr.0x2)
tSMPL
= register (addr.0x1)
tConv1
tConv2
tConv3
= tPON + tDLY1 + (tTIME_ST_ADC + (tADC * tSMPL) * 2 + tDLY2)
= tPON + tDLY1 + tTIME_ST_ADC + (tADC * tSMPL) + tDLY2
= tDLY1 + (tADC * tSMPL) + tDLY2
(*1) Time is calculated with the oscillating frequency of the internal OSC at 8MHz.
(*2) In case PDM=1, tPON(s) is set to zero except for the first one.
(*3) The dashed part is required only when apply time set for a panel is more than TIME_ST_ADC.
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TSZ22111・15・001
14/26
TSZ02201-0Y1Y0F300120-1-2
11.Nov.2013 Rev.002