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beaglebone prints CCC on the serial connection when powered on.
I'm trying to make gpioLEDblink.c work in SD card. I'm using MLO image in the binary/.../bootloader which is dated as Aug/6/2012. I compiled gpioLEDblink, then renamed it to 'app'. All these were done in Ubuntu guest in VirtualBox, then I copied both of them to the Windows host machine to use "TI_SDCard_boot_utility_v1_0.exe". It formats my SD card whenever I click the "Proceed" button. But, anyway, it seems to make the SD card partition bootable and copied MLO and app to the card.
Then I inserted the microSD to beaglebone, then connected USB cable to power on (I don't use adapter). I opend Putty to see messages from the serial connection. But it only prints "CCCCCCCCCC", which, I read somewhere, means UART booting sequence, waiting for boot image from the host.
I also tested my own boot_ti.bin image built in CCSv5 in ubuntu. I used Debug_MMCSD configuration for compilation. Then, I copied boot_ti.bin to Windows, renamed it to MLO then used the "TI_SDCard....." to load it with app to microSD card. No luck. I saw the same 'CCCCCCCCCCCCCCCCC' over and over again.
Could you give me some clue?
Hello sang gang,
the CCC clearly indicates that the AM335x is trying to boot via UART0 (see TRM chapter 22.214.171.124). In order to let the AM335x boot via SD-card, you have to change the boot configuration of the SYSBOOT[4:0] signals on your BeagleBone (see page 6 of the schematic). The large table 26-7 in the TRM outlines the choices. Perhaps 10111b (MMC0 first, then SPI0, then UART0 and USB0 as the last) is the required boot configuration for you.
Thanks for reply. But I don't understand what you mean. I read in the Starterware user guide that the TI evaluation board is configurable for boot mode using dip switch, but BeagleBone is hardwired for SD boot only. That's why I was very confused by the symptom. Or maybe I'm wrong. But, I couldn't find any information related to it. BTW, where can I get TRM? I have BeagleBone System Reference Manual, but I couldn't find TRM.
Update: Well I found the information. BeagleBone is configurable for boot mode using some headers. But that's strange. The default boot mode is SD card, then why does it show CCCCCC? And, if I use those header lines, I cannot use the board as I want. Anyway, I'll try testing.
The beaglebone has a hard wired boot order of mmc0 -> spi0 -> uart0 -> usb0. That means it tries mmc first. If no bootable image is found it tries spi. If no bootable image is found it tries uart (which is when you see the CCC) and finally usb. For some reason when you are trying to boot from mmc the boot rom doesn't think your image is bootable.
To get the TRM, you can go to www.ti.com and search for am335x. One of the links found will be to the TRM.
thank you for the clarification. If nobody has altered the boot configuration on sang gang's BeagleBone, does this mean his SD-card is not formatted correctly?
@sang gang: here is the TRM: http://www.ti.com/litv/pdf/spruh73f
It sounds like the card is not formatted correctly. I have not used that Windows utility to format a card so I'm not familiar with it.
Hi Steve, Ruediger,
Based on your input, I guessed that the TI_SDCard..... utility is not great on making the partition active boot. And that turned out to be the reason. I made it active boot partition, and it worked. I used fdisk in ubuntu.
Thanks a lot for your interest and concern,
Also see this thread
for useful information on this topic.
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