Microchip Technology AC164127-6 数据表
PIC24FJ256DA210 Development Board User’s Guide
DS51911A-page 42
2010 Microchip Technology Inc.
4.4.4.3
RESISTIVE TOUCH SCREEN INTERFACE
The development board supports display panels with a built-in 4-wire resistive touch
screen. The resistive touch screen interface (X-, Y-, X+ and Y+) is used to directly con-
nect to the touch screen signals. X+ and Y+ are both analog and digital signals, and
are connected to I/O ports that can function both as analog inputs and digital outputs.
X- and Y- are digital output signals only, and are connected to digital I/O ports. The X+
and Y- signals are multiplexed with the SPI based touch screen controller.
screen. The resistive touch screen interface (X-, Y-, X+ and Y+) is used to directly con-
nect to the touch screen signals. X+ and Y+ are both analog and digital signals, and
are connected to I/O ports that can function both as analog inputs and digital outputs.
X- and Y- are digital output signals only, and are connected to digital I/O ports. The X+
and Y- signals are multiplexed with the SPI based touch screen controller.
When using the 4-wire resistive touch screen interface, jumpers JP9 and JP10 must be
set to their default positions, bridging pins 1 and 2 (Figure 4-7, callout 1).
set to their default positions, bridging pins 1 and 2 (Figure 4-7, callout 1).
4.4.4.4
SPI TOUCH CONTROLLER INTERFACE
Two SPI channels (two Chip Select lines) are provided in Display Connector V1 to
support display panels equipped with the following:
support display panels equipped with the following:
• SPI-Based Timing Controller: Some displays requires programming of an
on-board Timing Controller (TCON) to initialize the settings of the display before it
is used. The TCON is used to synchronize the display glass timing with the dis-
play controller signal timing. This option is provided on the pins A27 (SPI_SCK),
A28 (SPI_MISO), B27 (DISP_SPI_CS) and B28 (SPI_MOSI) of display connector
V1.
is used. The TCON is used to synchronize the display glass timing with the dis-
play controller signal timing. This option is provided on the pins A27 (SPI_SCK),
A28 (SPI_MISO), B27 (DISP_SPI_CS) and B28 (SPI_MOSI) of display connector
V1.
• SPI-Based Touch Controller: In some cases, an SPI-based touch module is used
with the display. Every time a touch is detected, it sends an interrupt to the host
controller to inform the host that there is a fresh touch input and the information
must be forwarded from the touch module to the host controller through SPI com-
munications. The development board shares two of the pins of the 4-wire resistive
touch screen with the interrupt and chip select line of the SPI based touch control-
ler. The sharing is done this way since in any system, only one of the two types of
user interface will be used.
controller to inform the host that there is a fresh touch input and the information
must be forwarded from the touch module to the host controller through SPI com-
munications. The development board shares two of the pins of the 4-wire resistive
touch screen with the interrupt and chip select line of the SPI based touch control-
ler. The sharing is done this way since in any system, only one of the two types of
user interface will be used.
The SPI-based touch control features are configured by jumpers JP9 and JP10
(Figure 4-7, callout 1). To enable the use of an SPI-based touch controller, set jumpers
JP9 and JP10 to bridge positions 2-3.
(Figure 4-7, callout 1). To enable the use of an SPI-based touch controller, set jumpers
JP9 and JP10 to bridge positions 2-3.
FIGURE 4-7:
TOUCH CONTROLLER AND BACKLIGHT CONFIGURATION
Note:
As of this writing, none of the Microchip display boards support SPI-based
touch controllers.
touch controllers.
M
1
2