How to reconfigure of GPIO pins of UP board?

DDupboard

1) I want to know and learn how to reconfigure GPIO pins?
2) I want to set gpio pins as DPI parallel RGB888 output?

ccalde

Hi @DDupboard ,

Here you can find the pinout for the UP board:
https://wiki.up-community.org/Pinout

In the "Linux GPIO"column you will find the pin number to control via Linux command line.

Then, just control your GPIO exporting and configuring its parameters:
echo 26 > /sys/class/gpio/export
cat /sys/class/gpio/gpio26/direction
echo out > /sys/class/gpio/gpio26/direction
cat /sys/class/gpio/gpio26/value
echo 1 > /sys/class/gpio/gpio26/value

DDupboard

Is there possible to reconfigure GPIO pins as a DPI in Up-board?

ccalde

Hi @DDupboard ,

Yes, you must to reconfigure your GPIO pins to enable your DPI.
Check the pinout for a DPI on RPI:
https://pinout.xyz/pinout/dpi

The upboard pinout is equal to the RPI:
https://wiki.up-community.org/Pinout

DDupboard

Okay great,

After some process, neither I installed GPIO package to board nor reconfigure GPIO pins with command you gave!

With command : echo 26 > /sys/class/gpio/export
Message display in normal mode : bash: /sys/class/gpio/export: Permission denied
Message in root mode : -bash: echo: write error: Invalid argument

What will the next steps any suggestions?

ccalde

Hi @DDupboard ,

You have to work as root user.
First at all, type: sudo -i
Then, type your command again, please.

DDupboard

Okay, I tried in root mode mode also but still not allow to access file!

Same issues: Permission Denied

ccalde

Hi @DDupboard ,

Something is wrong in your side because I just tested it and it looks fine as normal.

ccalde

First, confirm to me you have the supported Ubuntu software installed: Ubuntu 16.04 and kernel 4.15 for UP board:
https://wiki.up-community.org/Ubuntu

ccalde

Then, follow the steps to access to your GPIO as normal:
upboard@upboard-UP-CHT01:~$ sudo -i
[sudo] password for upboard:
root@upboard-UP-CHT01:~#
root@upboard-UP-CHT01:~# echo 26 > /sys/class/gpio/export
root@upboard-UP-CHT01:~# cat /sys/class/gpio/gpio26/direction
in
root@upboard-UP-CHT01:~# echo out > /sys/class/gpio/gpio26/direction
root@upboard-UP-CHT01:~# cat /sys/class/gpio/gpio26/value
0
root@upboard-UP-CHT01:~# echo 1 > /sys/class/gpio/gpio26/value
root@upboard-UP-CHT01:~# cat /sys/class/gpio/gpio26/value
1

DDupboard

Here I use ubuntu 16.04 version
but still face same problem

ccalde

Hi @DDupboard ,

You are using a generic kernel 4.15.0-29.
Please, follow again the instructions to get Ubuntu 16.04 and kernel 4.15 supported for UP family:

https://wiki.up-community.org/Ubuntu#Install_Ubuntu_kernel_4.15.0_for_UP_from_PPA

Install and reboot your machine, and try again.

DDupboard

ERROR GOT WHEN FOLLOW STEP ON LINK

FACE STILL SAME PROBLEM

ccalde

Hi @DDupboard ,

Please, again, follow the full steps to get the kernel 4.15.0-37 in your Ubuntu 16.04.

After downloading the kernel using the sudo apt-get install linux-image-generic-hwe-16.04-upboard, you must reboot your machine.

DDupboard

hello,

I check the gpio setup and change its direction but not success to get parallel RGB output!

Can you help/guide me to change UP board GPIO to DPI format for 24bit Parallel RGB display format output?

Cause I set all gpio as out direction but confuse for how to set LCD_HSYNC, LCD_VSYNC. CLK, DE pins ?

ccalde

Hi @DDupboard ,

You must follow the next pinout tables for UP board and the DPI:
https://wiki.up-community.org/Pinout#Pinout_Table
https://www.raspberrypi.org/forums/viewtopic.php?t=133157

LCD_VSYNC = I2C1_SDA - pin 3
LCD_HSYNC = I2C1_SCL - pin 5
CLK = ID_SD - pin 27
DEN = ID_SC - pin 28

Notice physical pins and Linux GPIO pins have different number codification.

DDupboard

Hello,

Thank you for your valuable answer!

But, I have on doubt in gpio reconfigure like we can change either its direction (low and high) or values(0 and 1).
Then , How can I change pin 3 status - from I2C1_SDA to LCD_VSYNC ?

Hope for positive response!

Thanks.

ccalde

Hi @DDupboard ,

What do you mean??
The LCD_VSYNC is the DPI pin who should be connected to the I2C1_SDA UP board pin. They are pins from each board, end to end.

DDupboard

Thank you for answer.

Here, I2C1_SDA also work as LCD_VSYNC but when I prefer Intel Atom z8000 processor datasheet(UP board also use this processor) and see it GPIO function where I cannot find DPI mode!

And according to you I2C1_SDA work as LCD_VSYNC and I also try this pin as dpi mode and connect according it but not get any result.

Guide for further way!

ccalde

Hi @DDupboard ,

Unfortunately, UP board has never been validated for that kind of DPI interfaces.

I2C1_SDA doesn't work as LCD_VSYNC. I told you must connect the I2C1_SDA pin from your UP board to the LCD_VSYNC pin from the LCD display and in the same way for the rest of the pins.

You should be able to access to your display via I2C communication as it is suggested in that forum:
https://www.raspberrypi.org/forums/viewtopic.php?t=133157

aivision

Hi @DDupboard,

I am on a similar project and I need to implement DPI in the UP Board. I would like to know if you finally make it work. Thank you!