MAX11800_10 Datasheet, PDF (7/57 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 1. Terminology (continued)
TERM
DEFINITION
FIFO
First-In First-Out Memory: The MAX11800–MAX11803 contain a 1024-bit FIFO that is used to store conversion
results when operating in autonomous conversion mode. FIFO depth indicates the number of words (16-bit
quantity) in the FIFO.
Scan
Scan: Generally, a single sequence of operations performed in DCM or ACM. The operations could include a
panel setup operation, followed by a panel measurement operation, or a combined measurement operation.
Scan Block
Scan Block: Generally, a sequence of multiple operations performed in DCM or ACM. The operations could
include panel-setup operations, panel-measurement operations, or combined measurement operations.
Timed Scan
Timed Scan: A scan or scan block operation that uses the on-chip oscillator and timer. The timer is controlled
through the configuration registers and represents an array of fixed (time) quantities that are user selectable
(MAX11800/MAX11801).
Untimed Scan Untimed Scan: A scan or scan block operation that is controlled by the AP. This only applies to DCM.
TAG
Data Tag: Information appended to the end of an ADC conversion result. Tags indicate the type of measurement and
touch status associated with each panel observation. See the definitions for ETAG and MTAG (also in Table 1).
ETAG
MTAG
Event Tag: Data tags indicating the panel touch status observed during a measurement.
Measurement Tag: Data tag indicating the type of measurement read back by the AP (either X, Y, Z1, or Z2).
TIRQ
Touch Interrupt Request: Active-low interrupt, indicating that a touch is present (CINT) or has been initiated
(EINT) in DCM, or that new data is available in the FIFO in ACM.
EINT
Edge Interrupt Mode: Indicates, through TIRQ, that a touch has been initiated (EINT) in DCM. The duration that
TIRQ is low is user programmable.
CINT
Continuous Interrupt Mode: Indicates, through TIRQ, that a touch is present (CINT) in DCM. TIRQ goes low to
indicate the presence of a touch and stays low until the touch event ceases.
CORINT
Clear-on-Read Interrupt Mode: Used in ACM only. TIRQ goes low to indicate the presence of new FIFO data. The
interrupt is cleared when the data is read by the AP (MAX11800/MAX11801).
APER
CONT
Aperture Mode: Available in ACM only. Reduces data writes to the FIFO by spatially filtering measurement data.
Continuous Bit: An option in DCM to return the MAX11800–MAX11803 to a panel setup (wait) mode (PSU) after a
conversion, rather than a return to TDM (recommended only for applications with very long panel settling times and
request controlling their own averaging). The continuous bit resides in bit 0 (R0) of the PSU and PMC registers.
LPM
Low-Power Mode: An idle mode used in DCM/EINT or ACM modes, when a touch is detected at the conclusion of
the last measurement. This indicates a new measurement needs to be requested or scheduled (the touch-detect
pullup is not engaged to save power).
PUR
Pullup Rough: A fast pullup mode, which uses the main X+ switch in parallel with the on-chip resistive pullup
(50kΩ/100kΩ) to quickly slew the touch panel capacitances. R_PUR ≤ 10Ω typical.
PUF
SAR ADC
Pullup Fine: A slow (fine) pullup mode, which uses the on-chip resistive pullup to slew the touch-panel
capacitances to their final values (R_PUF = 50kΩ or 100kΩ) typical and is required for all applications.
Successive Approximation Register ADC: An analog-to-digital converter that converts a continuous analog
waveform into a discrete digital representation through a binary search through all possible quantization levels
before finally converging upon a digital output for each conversion.
Inter-Integrated Circuit: A multimaster serial computer bus that is used to attach low-speed peripherals to other
I²C
components using two bidirectional open-drain lines, serial data (SDA) and serial clock (SCL), pulled up with
resistors.
SPI
Serial Peripheral Interface: A serial interface in which a master device supplies clock pulses to exchange data
serially with a slave over two data wires (master-slave and slave-master).
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