MAX1233_05 Datasheet, PDF (21/45 Pages) Maxim Integrated Products – ±15kV ESD-Protected Touch-Screen Controllers Include DAC and Keypad Controller

±15kV ESD-Protected Touch-Screen
Controllers Include DAC and Keypad Controller
Bits 14-15: Pen Interrupt Status and
ADC Status Bits
These bits are used to control or monitor ADC scans.
Bits 10-13: ADC Scan Select
These bits control which input to convert and which con-
verter mode is used. The bits are identical regardless of a
read or write. See Table 7 for details about using these bits.
Bits 8-9: ADC Resolution Control
These bits specify the ADC resolution and are identical
regardless of read or write. Table 8 shows how to use
these bits to set the resolution.
Bits 6-7: Converter Averaging Control
These bits specify the number of data averages the
converter performs. Table 9 shows how to program for
the desired number of averages. When averaging is
used, ADSTS and BUSY indicate the converter is busy
until all conversions needed for the averaging finish.
These bits are identical, regardless of read or write.
Bits 4-5: ADC Conversion Rate Control
These bits specify the internal conversion rate, which
the ADC uses to perform a single conversion, as shown
in Table 10. Lowering the conversion rate also reduces
power consumption. These bits are identical, regard-
less of read or write.
Table 5. ADC Control Register Bit Descriptions
BIT
15 (MSB)
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0 (LSB)
NAME
PENSTS
ADSTS
A/D3
A/D2
A/D1
A/D0
RES1
RES0
AVG1
AVG0
CNR1
CNR0
ST2
ST1
ST0
RFV
DESCRIPTION
Read: pen interrupt status; Write: sets interrupt initiated touch-screen scans
Read: ADC status; Write: stops ADC
Selects ADC scan functions
Selects ADC scan functions
Selects ADC scan functions
Selects ADC scan functions
Controls ADC resolution
Controls ADC resolution
Controls ADC result averaging
Controls ADC result averaging
Controls ADC conversion rate
Controls ADC conversion rate
Controls touch-screen settling wait time
Controls touch-screen settling wait time
Controls touch-screen settling wait time
Chooses 1.0V or 2.5V reference
Table 6. ADSTS Bit Operation
PENSTS
0
ADSTS
0
READ FUNCTION
WRITE FUNCTION
No screen touch detected;
scan or conversion in progress
Performs one scan and waits to detect a screen touch. Upon
detection, issues an interrupt and waits until told to scan by the
host controller.
1
0
Screen touch detected;
Stops any ongoing scan and waits to detect a screen touch. Upon
scan or conversion in progress detection, issues an interrupt and performs a scan.
0
1
No screen touch detected;
data available
Stops any ongoing scan and waits to detect a screen touch. Upon
detection, issues an interrupt and waits until told to scan by the
host controller.
1
1
Screen touch detected;
Stops any ongoing scan and powers down the screen touch
data available
detection circuit. No screen touches are detected in this mode.
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