UR7HCTS2-S840 Datasheet, PDF (7/16 Pages) Semtech Corporation – High-Performance, Low Power Touch Screen Controller/Digitizer

SERIAL PERIPHERAL INTERFACE (SPI) AND ASYNCHRONOUS SERIAL INTERFACE (SERIAL)
The ScreenCoder^TM SPI/Serial
supports either Serial Peripheral
Interface (SPI) or Asynchronous
Serial Interface (Serial)
communication based on the
power-up setting of the ISEL/SCLK
pin. To select the Asynchronous
Serial Interface, connect
ISCL/SCLK to VSS. For SPI
interface, SCLK must idle high.
Data Packet Format for
ScreenCoder^TM SPI/Serial
The ScreenCoder^TM SPI/Serial has
two different types of mouse
packages. One type is for absolute
position data from the touch screen
sensor and one is for relative data
from the external PS/2 device.
For both the Relative and Absolute
mode package format, each
packet contains 4 bytes. The 7th
bit of each byte is used for
synchronization. The 7th bit for the
first byte is 1 and for the other
bytes is 0. The resolution for
absolute position is 10 bits
(approximately 1000 points in X
and Y directions.) The relative
mouse data format supports
operations with WheelMouse and
5-button mice.
ABSOLUTE MODE PACKAGE FORMAT
Byte # 7
1
1
2
0
3
0
4
0
6
0
Mouse
Y9
X6
Y6
Bit Number
5
4
3
2
1
0
0
0
0
0
0
0
Absolute 1 penup 1 penup 1 penup 1 penup 1 penup
Y8
Y7
X*
X9
X8
X7
X5
X4
X3
X2
X1
X0
Y5
Y4
Y3
Y2
Y1
Y0
RELATIVE MODE PACKAGE FORMAT
Byte # 7
1
1
2
0
3
0
4
0
Bit Number
6
5
4
3
2
0
1
Ysign Xsign M
Mouse Relative
X6
X5
X4
X3
X2
Y6
Y5
Y4
Y3
Y2
X*
B5
B4
Z3
Z2
1
0
R
L
X1
X0
Y1
Y0
Z1
Z0
Note 2: The bits that are marked with X* are reserved for future use. Now the value given is
zero.
Note 3: The X / Y data from external mouse is 9 bits. In our report, we truncate it to 8 bits.
The reduction is based on the fact that X / Y increments are seldom beyond the range of
+127/-128. For mouse data that exceeds this range, the ScreenCoder^TM SPI/Serial will give
+127/-128.V8-V0: Revision
Hex 40 (Current Revision here)
IDENTIFICATION AND REVISION REPORT PACKAGE FORMAT
Bit Number
Byte # 7
6
5
4
3
2
1
0
1
1
0
0
0
0
0
0
1
2
0
F4
V8
V7
C3
C2
C1
C0
3
0
P2
P1
P0
F3
F2
F1
F0
4
0
V6
V5
V4
V3
V2
V1
V0
(See Note 4 below)
Identification and Revision for
ScreenCoder^TM SPI/Serial
The UR7HCTS2-S840 offers a
special identification and revision
package. This package uses the
absolute mode format, but will not
appear in the normal absolute
mode. For normal absolute mode,
the first byte will be 80 Hex or 9F
Hex. This special 4-byte package
is identified by the first byte, 81
Hex. This data package is sent
upon power-up.
Note 4:
C3-C0: Class ID
F4-F0: Family ID
P2-P0: Sub Product Family
V8-V0: Revision
Hex 7
Hex A
Hex 1
Hex 40
UR7HC
TS2
S840
(Current Revision here)
Copyright Semtech 2000-2001
7
DOC7-TS2-S840-DS-102
www.semtech.com