SparkFun Top pHAT Hookup Guide

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2.4" TFT Display (Archived)

Archived Instructions: The following instructions are only valid for Raspberry Pi OS (or Raspbian) distributions, prior to the Linux 5.4 update. This has been reported to have occurred with the Aug 2020 release (2020-08-20).

There are two steps for the modules required for the 2.4" TFT Screen; adding the driver modules and then a module configuration.

Add Driver Modules

Use your preferred text editor to add the required modules to /etc/modules. The example below uses nano with the following command: sudo nano /etc/modules.

Add the following lines in the file:

spi-bcm2835
fbtft_device

Add modules
Adding modules for the screen. (Click to enlarge)

Module Configuration

Again, use your preferred text editor to add the required modules to /etc/modprobe.d/fbtft.conf.

Add the following text to the file:

options fbtft_device name=fb_ili9341 gpios=reset:23,dc:24 speed=16000000 bgr=1 rotate=180 custom=1

Configure module
Configuration for fbtft module. (Click to enlarge)

Once these changes have been made, reboot the Raspberry Pi with the sudo reboot command for the changes to take effect.

Note: Users with the touch screen (from the initial release) should, instead, add the following text to configure the screen properly:

options fbtft_device name=fb_ili9341 gpios=reset:23,dc:24 speed=16000000 bgr=1 rotate=180 custom=1 init=\
-1,0x28,-2,20,-1,0x21,-1,0xCF,0x00,0x83,0x30,-1,0xED,0x64,0x03,0x12,0x81,-1,0xE8,0x85,0x01,0x79,\
-1,0xCB,0x39,0x2c,0x00,0x34,0x02,-1,0xF7,0x20,-1,0xEA,0x00,0x00,-1,0xC0,0x26,-1,0xC1,0x11,\
-1,0xC5,0x35,0x3E,-1,0xC7,0xBE,-1,0xB1,0x00,0x1B,-1,0xB6,0x0a,0x82,0x27,0x00,-1,0xB7,0x07,\
-1,0x3A,0x55,-1,0x36,0x38,-1,0x11,-2,120,-1,0x29,-2,20,-3

For users, unsure about the production model they have, the Top pHAT has separate SKUs. However, the most apparent differences are the screen's colors appear inverted when using the wrong setting; or the chip on the screen's ribbon cable that is utilized for the touch capability.

DEV-16301


Initial product release with touch screen. The additional chip for the touch capability can be seen on the right, attached to the ribbon cable.

DEV-16653

Updated product release without the touch capability; no chip is attached to the ribbon cable. The touch screen was initially used due to supply shortages.

Screen Operation

To utilize the screen, users will call the con2fbmap command. The command is followed by two inputs; the terminal to be displayed and the frame buffer, in that order.

List Frame Buffer

Get the input for the frame buffer, use the cat /proc/fb, it will list what the fb numbers are.

Show frame buffers
Listing frame buffers. (Click to enlarge)

List Users and their Terminals

To list the active users and their terminals, the who command can be used.

List user terminals
Listing active user terminals. (Click to enlarge)

Note: Users cannot display a hardware terminal like the serial console on the screen.

Examples

Below is are some examples for using the screen. (*Don't forget to reboot the Raspberry Pi for the previous configurations to take effect.)

  • Display terminal on the TFT using the con2fbmap 1 1 command in the terminal or CLI. Then exit to the virtual terminal using Ctrl + Alt + F1.
  • To swap between the display and the HDMI output, use the startx command in the terminal or CLI initiate the PIXEL desktop through the HDMI output. To revert back to the display, click on Raspberry Pi icon -> Shutdown -> Exit to Commandline.
  • In order to utilize the display on startup, users can modify the /etc/rc.local file using the sudo nano /etc/rc.local command in the terminal or CLI. Users will need to add the con2fbmap 1 1 command just above the exit 0 entry.

Screen operational
Screen operating from boot. (Click to enlarge)

Note: The HDMI can be hot plugged into a Raspberry Pi 3 only. On the Pi 4, an HDMI cable must be plugged in before booting.