Connecting the EXT3 to the Raspberry Pi Zero and B

Scope

This configuration has been tested successfully against
  • Raspberry Pi Zero for all the screens up to 12.2" included;
  • Raspberry Pi 3B for all the screens up to 12.2" included;
with two GPIO libraries:
  • RasPiArduino port for Arduino;
  • BCM2835 library for native applications;
  • MRAA library for native applications.

RasPiArduino port for Arduino

Software

On the main sketch, set the board to boardRaspberryPiZeroB_RasPiArduino, corresponding to the pins defined in the hV_Configuration.h file of the ePaper_EXT3_Basic_Library (link 1, link 2).

Notes

I am using the excellent RasPiArduino port of Arduino to the Raspberry Pi.

The executable needs to be run with sudo in order to have access to the I²C and SPI ports.

The I²C bus freezes occasionally with the RasPiArduino library.
Sketch.ino

    










	

    

        
hV_Configuration.h

    

    

        

    









					
									

		
	





Hardware





Picture









Picture







Native applications with BCM2835 library



Software




	

		
			

				
					
						


For applications running natively on the Raspberry Pi, I recommend the BCM2835 library with the corresponding connections, based on the GPIOs names. 

​On the main sketch, set the board to boardRaspberryPiZeroB_RasPiArduino, corresponding to the pins defined in the hV_Configuration.h file of the ePaper_EXT3_Basic_Library (link 1, link 2).



Notes



The executable needs to be run with sudo in order to have access to the I²C and SPI ports.

When used, the SPI pulls high GPIO8 CE0 pin 24 and GPIO7 CS1 pin 26. The connections are adapted accordingly.

The I²C bus doesn't freeze with the BCM2835 library.



					
										
					
						



	

    

        
Sketch.ino

    

    

        

    










	

    

        
hV_Configuration.h

    

    

        

    









					
									

		
	





Hardware





Picture







Native applications with MRAA library




	

		
			

				
					
						


For applications running natively on the Raspberry Pi, I also recommend the MRAA library with the corresponding connections based on the pins numbers (and not the GPIOs names). 

​On the main sketch, set the board to boardRaspberryPiZeroB_MRAA, corresponding to the pins defined in the hV_Configuration.h file of the ePaper_EXT3_Basic_Library (link 1, link 2).



Notes



The executable can be run with normal privileges.

The MRAA library also supports other single board computers like the BeagleBone.



					
										
					
						



	

    

        
Sketch.ino

    

    

        

    










	

    

        
hV_Configuration.h

    

    

        

    









					
									

		
	





Options




	

		
			

				
					
						


Large screens 9.7" and 12.2" require panelCSS to be defined and connected.

If the second memory is populated on the EXT3 board, flashCSS needs to be defined and connected. The library will keep flashCSS HIGH to avoid any interferences with the other devices connected to the SPI bus.



					
										
							

		
	






Posted: 28 Feb 2021
Updated: 24 May 2021, 24 Aug 2021, 15 Nov 2021, 30 May 2022