MAX11800_10 Datasheet, PDF (27/57 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
Table 8. Panel Setup Command Summary
HEX R6 R5 R4 R3 R2 R1 R0 ACCESS
6xh
1
1
0
1
0
0 (1)
Write
6xh
1
1
0
1
0
1 (1)
Write
6xh
1
1
0
1
1
0 (1)
Write
6xh
1
1
0
1
1
1 (1)
Write
PAIRABLE
No
No
No
No
COMMAND
LENGTH
8
8
8
8
OPERATION
X = panel setup
Y = panel setup
Z1 = panel setup
Z2 = panel setup
Panel Setup Commands
Panel setup commands configure the touch panel prior to
a measurement. Panel setup commands allow the panel
to fully settle before performing a measurement. The
panel setup command summary is shown in Table 8. See
the register map in the Status and Configuration Registers
section for details on the panel setup timing options for X,
Y, Z1, and Z2 measurements.
The continuation bit (CONT) of the panel setup com-
mand programs the MAX11800–MAX11803 to maintain
the present panel setting at the end of the command
(CONT = 1). Panel setup commands assume a logical
progression to an appropriate measurement. For exam-
ple, when the MAX11800–MAX11803 are in the X panel
setup mode, the devices can proceed to an X measure-
ment mode only. The devices return to LPM when an
incompatible command follows a panel setup com-
mand. See Figure 11.
Panel Measurement Commands
A measurement command selects one of the four phys-
ical setup options: X, Y, Z1, or Z2. The panel measure-
ment command summary is shown in Table 8.
All panel measurement commands include timed inter-
vals to power up both the internal ADC and the panel
with programmable durations. The delayed conversion
time (t_{D_CV}, delayed conversion configuration register
(0x06)) governs the time that the panel and the ADC
need to settle prior to the initiations of conversions. The
minimum delayed conversion time is 10μs, which is the
time the internal ADC needs to power up. If more set-
tling time is required, increase the panel settling time
by delaying the conversion time or by adding an addi-
tional panel setup time (t_PSU) using the panel setup tim-
ing configuration register (0x05). The advantage of
using a dedicated panel setup time is that the ADC
does not consume power during this interval. The
required panel setup time is a function of the panel
end-to-end resistance, the capacitance of the panel,
and any board-level components.
LPM
N
X PSU CMD
Y
N
X MEAS CMD
Y
N
Y PSU CMD
Y
N
Y MEAS CMD
Y
N
Z1 PSU CMD
Y
N
Z1 MEAS CMD
Y
N
Z2 PSU CMD
Y
N
Z2 MEAS CMD
Y
Figure 11. Command and Measurement Flow (DCM)
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