On Sat, 3 Oct 2015 09:23:35 +0530 Rock Slate <rockslat...@gmail.com> wrote:
> Hi, > > In general I know the x86 architecture BIOS will refuse to boot if valid > ram space is not found. On linux I can use the BadRam kernel patches to > ignore bad areas of memory. However just out of curiosity, I am wondering > whether using the internal cache would be sufficient to run small programs > to access GPIOS. Right now I am not talking about booting Linux. I want to > know if I can run some really small RTOS on A13 without RAM? Hi, The A13 SoC has 48KiB of SRAM, which is used to run the initial part of the bootloader. The DRAM is even not initialized at this step. This initial part of the bootloader is loaded by the BROM from the SD card, NAND or other standard locations. But it needs to have a special magic signature and a valid checksum. Also there is a size limitation for it (something between 24KiB and 32KiB). You can check the http://linux-sunxi.org/BROM page for a brief description of the boot sequence. And also the A13 user manual for the rest of the information. For bare-metal programming experiments, you can also try to use FEL mode and upload & execute snippets of code over USB. So that you don't need inserting and removing SD cards all the time. Regarding the use of the L2 cache (256KiB) for additional data storage, this may be an interesting research topic. I can't say offhand whether it can be really configured this way and used safely. Are you planning to design an A13 board without DDR3, tailored for some special purpose? -- Best regards, Siarhei Siamashka -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to linux-sunxi+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
