ST EVALSPEAr320HMI, User Manual, Page: 12 / 36

Block descriptions and configurations EVALSPEAr320HMI
12/36 Doc ID 18410 Rev 3
4.3.2 Connecting a touch screen
See also: STMPE811 touch screen connectors (CN600 & TS_CN600) on page 20
The expansion board provides two ways to use the SPEAr320 touch screen interface.
●
The first is based on the SPEAr320 internal Touch IP block, and can be used by means
of the TS_xxx block (in the schematics) and the TS_CN600 interface connector.
● The second uses the standalone external touch screen controller, STMPE811 (U600).
STMPE811 is interfaced by means of the I2C bus and interrupt output pin.
The STMPE811 has:
– A 4-wire touch screen controller (CN600)
– A multiplexed general purpose input/output (GPIO) port expander, or an 8-input,
12-bit ADC (the default configuration).
– Temperature sensor
The STMPE811 (U600) internal temperature sensor can be used for informative
temperature measurements, such as a reference for compensation of the touch
screen parameters.
Temperature measurement is optimized for temperatures from 0 to 85
o
C.
– User potentiometer
A 10 K
Ω
potentiometer is available on the board, connected to the analog input
AIN0 of the STMPE811 (U600).
– User buttons
The remaining pins of the STMPE811 (U600) touch screen controller are used to
service two user buttons (B600, B601) that are connected to the GPIO pins IO2
and IO3.
All temperature measurements, potentiometer voltage measurements, and button
status information is available by means of the I2C bus.
Any of these tracked parameters can trigger a preconfigured interrupt event that is
subsequently signaled to the SPEAr320 MPU by means of the STMPE811 Interrupt
line.
SB606, SB607 :
Green LSB setting
Green LSB bit connected to the green MSB bit
SB606: open
SB607: closed
Intensity bit connected to the green LSB bit
SB606: closed
SB607: open
SB608, SB609 :
Red LSB setting
Red LSB bit connected to the red MSB bit
SB608: open
SB609: closed
Intensity bit connected to the red LSB bit
SB608: closed
SB609: open
Table 4. J601 configuration options (unified interface displays) (continued)
Jumper Description Configuration
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