MAX11800_1010 Datasheet, PDF (27/59 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
PANEL
TOUCH
BEGINNING OF TOUCH EVENT
END OF TOUCH EVENT
TIRQ
t_IRQ
INITIATED AND CONTROLLED BY
THE AP
TDM
LPM
LPM
TDM
DCM SCAN
DCM SCAN
DCM SCAN
ETAG = 00
ETAG = 01
ETAG = 10
t_AP
t_SD
READBACK OPERATIONS ARE NOT SHOWN, BUT ARE EXECUTED DURING TDM PERIODS.
TIRQ DURATION (t_IRQ) IS SPECIFIED BY THE GENERAL CONFIGURATION REGISTER (0x01).
SCAN INTERVAL (t_AP) IS CONTROLLED BY THE AP AND THE INITIATION OF DM SCAN EVENTS.
SCAN DURATION (t_SD) IS A FUNCTION OF THE SCAN TYPE AND CONFIGURATION SETTINGS.
DCM = DIRECT CONVERSION MODE
Figure 10. Edge Interrupt Mode (Direct Conversion Mode)—MAX11800–MAX11803
Table 8. Panel Setup Command Summary
HEX
0x69h
0x6Bh
0x6Dh
0x6Fh
ACCESS
Write
Write
Write
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. For most applications adequate
time for panel setup is available as an integral part of
the panel measurement commands; configured using
the panel setup timing configuration register, 0x05. The
dedicated panel setup commands are primarily provid-
ed to support applications where the AP needs to con-
trol panel setup directly or long panel setup time is
required.
Panel Measurement Commands
A measurement command selects one of the four phys-
ical setup options: X, Y, Z1, or Z2.
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
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