MAX11800_10 Datasheet, PDF (43/57 Pages) Maxim Integrated Products – Low-Power, Ultra-Small Resistive Touch-Screen Controllers with I2C/SPI Interface

Low-Power, Ultra-Small Resistive Touch-Screen
Controllers with I²C/SPI Interface
4) I²C Readback Registers: 52h to 58h
• Direct conversion mode only (MAX11801/
MAX11803)
• Allows reading measurement results when in DCM
5) Panel Setup Commands: 6Ah to 6Fh
• Sets up panel prior to making X, Y, Z1, or Z2 mea-
surements
6) Measurement Commands: 70h to 7Fh
• Performs specified measurement (X, Y, Z1, and/or
Z2)
The commands to read or write the user-accessible
registers are always the same. However, the data for-
mat varies based on whether using an SPI or I²C inter-
face. Tables 16 and 17 show the differences between
SPI and I²C protocols. For SPI, the R/W bit is embed-
ded in the 8-bit byte and always occupies the LSB
position. For I²C, the protocol is always 8-bit byte fol-
lowed by an acknowledge bit, for a total of 9 bits. The
MSB in I²C format is always 0. In write mode, for I²C,
the MSB is ignored internal to the MAX11800–
MAX11803, so setting it to 0 or 1 has no effect.
Status and Configuration Registers
The status and configuration registers are located in
block 0x00 to 0x0B. See Table 18. All user-configura-
tion register write mode operations are pairable within
the SPI/I²C interface. Multiple locations can be written
under a single instruction with a register byte followed
by a data. All user-configuration read-mode operations
support autoincrement. For example, if location 0x00 is
read back and more clock pulses are issued, readback
will proceed through location 0x01 and so forth. The
user should set all configuration registers to the desired
values before issuing direct conversion operations or
placing MAX11800/MAX11801 in autonomous mode.
Table 16. SPI Command and Data Format: 8 Bits
BIT 7
BIT 6
BIT 5
BYTE
BIT 4
BIT 3
R6
R5
R4
R3
R2
Command or Data
BIT 2
R1
BIT 1
R0
(CONT)
BIT 0
R/W
1/0
Table 17. I²C Command and Data Format: 8 Bits Plus ACK
BIT 7
0
BIT 6
R6
BIT 5
R5
BYTE
BIT 4
BIT 3
R4
R3
Command or Data
BIT 2
R2
BIT 1
R1
BIT 0
R0
(CONT)
ACK
BIT
1/0
1/0
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