blprasad Posted July 15, 2018 Share Posted July 15, 2018 (edited) 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. Link to comment Share on other sites More sharing options...
blprasad Posted July 19, 2018 Author Share Posted July 19, 2018 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. Link to comment Share on other sites More sharing options...
blprasad Posted July 26, 2018 Author Share Posted July 26, 2018 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. Link to comment Share on other sites More sharing options...
blprasad Posted July 26, 2018 Author Share Posted July 26, 2018 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. Link to comment Share on other sites More sharing options...
martinayotte Posted July 26, 2018 Share Posted July 26, 2018 1 hour ago, blprasad said: I have not tried hit any key method to stop auto boot Use "spacebar" to stop u-boot... Link to comment Share on other sites More sharing options...
blprasad Posted September 5, 2018 Author Share Posted September 5, 2018 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 Link to comment Share on other sites More sharing options...
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