MAX11800_1010 Datasheet, PDF (28/59 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 9. Panel Measurement Command Summary
HEX
0x70h
0x72h
0x74h
0x76h
0x78h
0x79h
0x7Ah
0x7Bh
0x7Ch
0x7Dh
0x7Eh
0x7Fh
ACCESS
Write
Write
Write
Write
Write
Write
Write
Write
Write
Write
Write
Write
PAIRABLE
No
No
No
No
No
No
No
No
No
No
No
No
COMMAND LENGTH
8
8
8
8
8
8
8
8
8
8
8
8
FUNCTION
X, Y = combined command measurement
X, Y, Z1 = combined command measurement
X, Y, Z1, Z2 = combined command measurement
AUX = conversion
X = measurement, CONT = 0
X = measurement, CONT = 1
Y = measurement, CONT = 0
Y = measurement, CONT = 1
Z1 = measurement, CONT = 0
Z1 = measurement, CONT = 1
Z2 = measurement, CONT = 0
Z2 = measurement, CONT = 1
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)
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.
When using a measurement command with CONT = 1 in
a direct conversion mode, the devices remain in the
requested setup mode in preparation for the succeeding
measurement. The panel does not return to TDM/LPM
and the interrupt status is not modified as a result of a
measurement command with CONT = 1 issued. See
Figure 12.
Combined Commands
In direct conversion modes, the panel returns to a TDM
at the conclusion of a combined command and all data
are tagged accordingly. The MAX11800–
MAX11803 then idle in a low-power mode determined
by the interrupt mode selected. See Figure 13.
Auxiliary Measurement Command
The MAX11800–MAX11803 support measurement of an
auxiliary input using the internal ADC in direct conver-
sion mode only. When programmed, the devices sam-
ple and quantize the voltage at AUX using V_DD as the
ADC reference. The MAX11800–MAX11803 store the
result in the same manner as X, Y, Z1, and Z2 measure-
ments, but do not add data tagging. The devices also
support averaging functions. Auxiliary measurements
do not require any panel setup procedure. There is no
28 ______________________________________________________________________________________