Sharp memory display generic shield
Overview
This is a generic shield for Sharp memory pixel LCD. It supports displays of LS0XX type. These displays have an SPI interface and few other pins. Note that the SCS is active high for this display.
The DISP pin controls whether to display memory
contents or show all white pixels, this can be connected
directly to VDD, to always display memory contents or connected
to a gpio. If devicetree contains disp-en-gpios then it will be set to
high during driver initialization. Display blanking apis can be used
to control it.
Sharp memory displays require toggling the VCOM signal periodically to prevent a DC bias occurring in the panel as mentioned in the appnote [1] and datasheet [2]. The DC bias can damage the LCD and reduce the life. This signal must be supplied from either serial input (sw) or an external signal on the EXTCOMIN pin.
Currently the driver only supports VCOM toggling using the EXTCOMIN pin
(EXTMODE pin is connected to VDD).
When extcomin-gpios is defined, driver starts a thread which will
toggle EXTCOMIN at extcomin-frequency frequency. Higher frequency
gives better contrast while lower frequency saves power.
To use a different method of toggling for example pwm, user may not
define extcomin-gpios and implement their preferred method in
application code.
Pins Assignment of the Generic Sharp memory Display Shield
Pin |
Function |
|---|---|
SCS |
Serial Slave Select |
SI |
Serial Data Input |
SCLK |
Serial Clock Input |
EXTCOMIN |
VCOM Inversion Polarity Input (VCOM can be controlled through SW) |
DISP |
Display ON/OFF switching signal (Can be connected directly to VDD) |
EXTMODE |
COM Inversion Selection |
Current supported displays
Following displays are supported but shield only exists for LS013B7DH03. Other shields can be added by using the LS013B7DH03 as a reference and changing the width, height, etc configurations.
LS012B7DD01 LS012B7DD06 LS013B7DH03 LS013B7DH05 LS013B7DH06 LS027B7DH01A LS032B7DD02 LS044Q7DH01
Display |
Shield Designation |
|---|---|
LS013B7DH03 |
ls013b7dh03 |
Requirements
This shield can only be used with a board that provides a configuration for Arduino connectors and defines node aliases for SPI and GPIO interfaces (see Shields for more details).
Programming
Set --shield ls013b7dh03 when you invoke west build. For example:
# From the root of the zephyr repository
west build -b nrf52840dk/nrf52840 --shield ls013b7dh03 samples/subsys/display/lvgl