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Connecting Logi Bone 2 and BBB

mhadamhada
in LOGI-Bone Discussion
Hi,

Is there any problem or extra care that should be taken when I connect factory programmed Logi Bone 2 and factory programmed BBB? What is expected in that case on Logi Bone 2.

Kindly help.

Comments

  • jpiatjpiat
    If the BBB is booting from the eMMC this can cause a conflict on the GPMC pins that will prevent the BBB from booting. If you boot from an SD card there is no problem at all. This boot problem comes from the fact that the LOGI-Bone eeprom declares the P8 pins as being controlled by the GPMC controller while Linux is accessing its filesystem and all through the eMMC. If you don't want the GPMC feature, you can still re-programm the eeprom to only declare the use of SPI and i2C or totally blank the eeprom so the LOGI-Bone is not auto-detected (can be done by booting on a sd card).
  • mhadamhada
    Hi, Thanks. Will come again once thought over it a little more...
  • mhadamhada
    Hi Jpiat,

    How are you? What if I keep the BOOT switch on permanently on the BBB so that I can boot my uC through JTAG directly and configure the FPGA on LB-2. In that case do I need to worry regarding the eMMC lines conflict with LB-2.

    Please tell.

    Regards
  • mhadamhada
    Hi jonathan, please reply as ou find time or tell me in case you find my question confusing...


  • jpiatjpiat
    Sorry but i'am notre sûre to understand. If you boot the BBB through JTAG and have your uc programming and to configure the FPGA, how is the eMMC involved ? If you don't use the GPMC bus in your FPGA design, there is no risk to interfer with the eMMC. If you want to use the GPMC, you 'll need to hold the eMMC in its reset state (the eMMC reset line is connected to the BBB processor).
  • mhadamhada
    Yes, this is what I wanted to make sure as to whether if still FPGA side had some issues.

    Again Jonathan, just to continue, what if I want to boot BBB using GPMC interface with a third card which has a NOR Flash and that NOR Flash holds the configuration file for FPGA of Logi Bone 2 [Configuration will be through I2C and SPI], can we boot through GPMC interface without removing or erasing eMMC? Can I power on BBB, rest the eMMC and then boot through GPMC is it possible?
  • jpiatjpiat
    Yes this should be possible because this how things are handlheld by the Kernel when the dvice tree configuration disable eMMC. On first version (without device tree) the eMMC was put in the reset state directly by the u-Boot bootloader with the line :

    mmcreset=mmc dev 1; mmc rstn 1; gpio set 52
    mhada
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