![]() ![]() In order to check if all is ok you can use the wiringpi library and in particular Or using the layer meta-raspberrypi you can set it via the RPI_EXTRA_CONFIG The simplest way (with a modern firmware) is to use the last option: in my case I canĪdd directly in the config.txt the following lines gpio=22-27=a4 create a device driver and move the pins using it.There are several options to go with to set the desired pins, each one needs (but the first one)Ī recent version of the firmware (you can see the version of your system using vcgencmd version) It directly to modify the registers is a pain in the ass. The chip of the raspberry pi has 54 pins configurable via 41 32-bit registers the startĪddress is different between board models, for a pi zero is 0x7e200000 but to use If you don't have already u-boot compiled you can use Yocto via these variables PREFERRED_PROVIDER_virtual / bootloader = "u-boot" KERNEL_IMAGETYPE = "zImage" KERNEL_BOOTCMD = "bootz"īoot.cmd that is obtained compiling boot.scr fdt addr $ GPIOsįor future use I want to set the pins needed to use JTAG with the board. Take in mind that some document uses fdt_addr_r instead of the mainline's fdt_addr. The address is passed as environment variable in u-boot. The complicated thing that happens with this device is that the start.elf prepareĪlready the fdt ( flat device tree) at a specific address and doesn't need to be loaded from the cmdline.txt instead contains the arguments for the kernel.Ĭmdline.txt dwc_otg.lpm_enable=0 console=serial0,115200 root=/dev/mmcblk0p2 rootfstype=ext4 rootwait console=tty0 ![]() This is achievable renaming accordingly the file or changing the right variable (named kernel) Kernel.img is usually the linux kernel, we want to substitute it with u-boot. stage 1: is the on-chip ROM, loads stage2 in the L2 cache.The raspberry pi, in particular the Broadcom chip, follows this Since I want to save the manual procedure for future use, what follows is theĮxplanation for the configuration, if you use the layer indicated above all this In order to use it with meta-raspberry you need only to set in nf ![]() (like RAM and flash) and to load the intended kernel with the correct parameters. a program that is used to setup the essential peripherals In the rest of the post I try to summarize how this is done. Layers in order to boot up a raspberry pi zero with U-Boot and configured to enable In my case I created a manifest with the minimal Of the repository with the specific revision and path that is needed to checkout in order a simple XML file) containing the description Way Android works: there is manifest (i.e. This way of configuring a project composed of multiple git repositories is inspired of the $ bitbake rpi-basic-image -c populate_sdk $ sudo dd if =tmp/deploy/images/raspberrypi0/rpi-basic-image-raspberrypi0.rpi-sdimg of =/dev/sdd $ source sources/oe-init-build-env build/ The following way $ mkdir rpi-yocto & cd rpi-yocto You can obtain an out-of-the-box configured Yocto tree using a manifest in This is a guide about building and configuring a Yocto build for a raspberry pi zero with u-boot.
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