Difference between revisions of "Unit HyperPixel"

Revision as of 04:15, 29 November 2021

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Description

Pimoroni HyperPixel TFT Display Driver unit

The HyperPixel is a TFT display produced by Pimoroni for use with the Raspberry Pi. It uses the DPI (Display Parallel Interface) which is directly supported by the VideoCore GPU and means that unlike other TFT displays using SPI or similar interfaces it supports hardware accelerated graphics in the same way as HDMI or DSI displays.

The HyperPixel is available in several versions including a 4.0 inch rectangular, a 4.0 inch square and 2.1 inch round. Each version requires a slightly different set of instructions to initialize it and this unit provides the correct sequence for each of these displays.

To use this unit simply include it in your application and then call the function HyperPixelInitialize() as early as possible passing the appropriate model as the only parameter to the function. Once initialized successfully the HyperPixel display will be available via the standard framebuffer functions and also via the VC4 accelerated graphics options such as OpenVG, OpenGLES, OpenMAX and MMAL.

It is important to remember that no other devices should be enabled while using the HyperPixel display as it consumes almost all of the available GPIO pins. So it is not possible to use UART, I2C, SPI, PWM etc when the HyperPixel is installed.

The touch screen controller varies between models and this unit creates and initializes the appropriate one for the model selected. All touch screen devices are I2C based however as it is not possible to utilize the hardware I2C controller (see note above) a software I2C host is created to provide access to the touch screen.

The touch events generated from the device can be read from the normal touch or mouse API functions in much the same way as any other touch or mouse device.

In order to enable the HyperPixel display you need to add the appropriate settings to your config.txt file as follows:

For HyperPixel 4.0 Rectangular (800 x 480)

enable_dpi_lcd=1
dpi_group=2
dpi_mode=87
dpi_output_format=0x7f216
dpi_timings=480 0 10 16 59 800 0 15 113 15 0 0 0 60 0 32000000 6

For HyperPixel 4.0 Square (720 x 720)

enable_dpi_lcd=1
dpi_group=2
dpi_mode=87
dpi_output_format=0x7f226
dpi_timings=720 0 15 15 15 720 0 10 10 10 0 0 0 60 0 35113500 6

For HyperPixel 4.0 Square (2021 or later) (720 x 720)

enable_dpi_lcd=1
dpi_group=2
dpi_mode=87
dpi_output_format=0x5f026
dpi_timings=720 0 20 20 40 720 0 15 15 15 0 0 0 60 0 36720000 4

For HyperPixel 2.1 Round (480 x 480)

enable_dpi_lcd=1
dpi_group=2
dpi_mode=87
dpi_output_format=0x7f216
dpi_timings=480 0 10 16 55 480 0 15 60 15 0 0 0 60 0 19200000 6

The display can be rotated to the desired position by adding the display_lcd_rotate setting to the config.txt file as below, please see the official documentation at https://www.raspberrypi.com/documentation/computers/config_txt.html for more details.

No Rotation

display_lcd_rotate=0

Rotate 90 degrees clockwise

display_lcd_rotate=1

Rotate 180 degrees clockwise

display_lcd_rotate=2

Rotate 270 degrees clockwise

display_lcd_rotate=3

Horizontal flip

display_lcd_rotate=0x10000

Vertical flip

display_lcd_rotate=0x20000

Constants

To be documented

Type definitions

HyperPixel specific types

Public variables

To be documented

Function declarations

To be documented

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