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TMS320C6657: Need more information on ROM code at address 0x20b00000

Bhaskar Kolakr
Prodigy 90 points
Part Number: TMS320C6657

Hi,

I want to boot a custom c6652 board from Direct SPI NOR boot.

I am able to boot EVM in direct spi nor boot. On reset i notice that the processor is at  0x20b00000 and executs some ROM code before loading the NOR code using SPI.

Can need more inforamtion on the above ROM coded and how i can use this on custom c6652 board.

Thanks

Bhaskar 

  • 0
    TI__Guru** 114410 points

    Bhaskar,

    The region 0x20b00000 is the base address of L2 ROM region on the chip where TI has programmed the primary boot loader also referred to as Boot ROM. This is fixed and can`t be modified. The ROM code reads the boot switches BOOTMODE[12:0], PCIEMODEx and PCIESSEN pin on the device and determines how to initialize the device and configure the boot mode and copy the image from the boot media.

    Even if you are using a custom board using C6652, the ROM code will remain the same the only difference will be external memory components like SPI NOR flash etc. the ROM code configures SPI in 4 pin mode and uses standard SPI NOR read command 0x3 to read from SPI so it should work with all NOR flash devices. The description of configuring boot on C665x is described in the following two documents.

    https://training.ti.com/system/files/docs/keystone-DSP-bootloader-user-guide.pdf

    http://www.ti.com/lit/ds/symlink/tms320c6652.pdf (Section 6.23 to section 6.29)

    Additional FAQ and resources have been shared on the KeystoneI Bootloader Resources and FAQ

    If you want to access the ROM code for reference, you can get them from the following link:

    http://software-dl.ti.com/sdoemb/sdoemb_public_sw/rbl/1_0_C6657/index_FDS.html 

    Regards,

  • 0 in reply to Rahul Prabhu
    Prodigy 90 points

    Thanks  for quick response. 

    -Bhaskar

  • 0 in reply to Bhaskar Kolakr
    Prodigy 90 points

    Hi,

    We are planning to use the C6652 for a safety critical system. We cant have a firmware (ROM boot code at 0x20b00000) running on power up, that is not verified and non-programmable.

    please let me know the way to boot from system reset and all the program is built by us.

    We need to run our program from reset vector. we dont want to use the pre-built ROM loader.

    Thanks

    Bhaskar     

  • 0 in reply to Bhaskar Kolakr
    TI__Guru** 114410 points

    Bhaskar,

    C6657 are not natively safety certified parts and always have the bootROM executing on the DSP when reset is asserted. EMIF NOR is the boot mode in which the device does least amount of setup and branches to code in the base of the EMIF CS0 address range. BootROM is required to setup device clocks and the boot media interface from where user application can be loaded for execution. 

    Our understanding of safety systems is that there is a initial state when safety function is not initialized and installed when the device doesn`t have to enforce functional safety goals. The system is considered to be functionally safe only when the safety function is initialized and is monitoring device for error stats using periodic diagnostics. Please correct us if this is not how your safety critical system needs to be designed. C6652 is off the shelf DSP processor which like most processors from TI needs to execute ROM function which can`t be modified to load the application.

    Regards,

    Rahul