Bare metal programming (Using GPIO-L directly)

scallozzo

Hello there,

Iam working on a simple bare metal project for the orange-pi zero. My program boots directly from sdcard (without uboot intervention). So, until now I got the uart0 and timer modules working properly, however Iam not able to use any of the R_xxxx registers, (R_UART, R_GPIO etc.).
I know that these modules are reserved for the CPUS however I sow a few bare metal examples that use the GPIO-L directly from the core0 with the only diference that they booted after uboot. My problem began when I tried to blink the power-led. It was not possible to change the port settings. I was able to readout the configuration but not to change the value over Port-L.
I guess there is something undocumented on the H3 datasheet.  
Any idea?

Thanks in advance.

Sebastián.-









        

dmx512

Hi Sebastián,
Had you any luck in solving your issue?
I can change the power led status in my bare metal code (soon to be posted here -> https://github.com/vanvught/rpidmx512), and yes, I boot from uBoot.
I am interested in your bootloader. Do you have it public?r