Uboot to display some text message to lcd.

[blprasad]

Hi all,

 

I am using Orange Pi 0, I am trying to show some initial booting message on LCD.

I am interfacing JHD204A which is a 20x4 charecter display.Which uses HD44780 controller.

Is there a way to access Pi 0 GPIOs from Uboot? So that I want to show some initial message on L

CD while Linux gets loaded. I appreciate any inputs, thanks in advance.

Edited July 26, 2018 by blprasad
Felt the meaning is inappropriate.

[blprasad]

It seems API like

   
    sunxi_gpio_set_cfgpin(pin,value);
    sunxi_gpio_output();

 

seems to be working in Uboot as well as these were working in Linux, there is a dirver already included in Uboot sources.

drivers/gpio/sunxi_gpio.c for accessing gpio.Need to experiment with Uboot.

[blprasad]

How do I boot Orange pi 0? , with Uboot only. I am trying to modify uboot.How can I test uboot prior to loading Linux.

I mean I would like to break the booting process at uboot.

Please help me.

[blprasad]

 I have not tried hit any key method to stop auto boot.I have just read about it in google.I will give it a try.

[martinayotte]

1 hour ago, blprasad said:

I have not tried hit any key method to stop auto boot

Use "spacebar" to stop u-boot...

 

[blprasad]

finally I am able to display text on LCD from Uboot.

sunxi_gpio_set_cfgpin(pin,value);
    sunxi_gpio_output();

are working from Uboot code, these calls are placed in pinmux.c in uboot.

   sunxi_gpio_input()  function is not present in pinmux.c so i copied it from gpio_lib.c and placed in pinmux.c 

 

thanks for inputs