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C6745 Bootloader and SPI0 Connection confusion

jintao Liu
Prodigy 30 points

I plan to use C6745 DSP  chip for our project .   I find C6745 SPI0 port and parts of BOOTLoader terminal using the same Pins. 

If SPI flash memory  is connected to SPI0 , how to connect  bootloader terminals ? ( Directly connecting or use other conntrol method ?)

If both of  them is connected to the same pins, how  to ensure bootloader can work correctly ?

  • 0
    TI__Guru** 116170 points

    The ROM code is referred to as the Bootloader which provides the c6745 chip the capability to load application code from different boot media. SPI0 flash is one of the boot media from which it can boot the application code. For this the boot loader code  expects the SPI flash to be connected to CS0. If you select the SPI flash boot mode, the boot loader accesses the SPI flash after power on reset to read the boot image, setup the device and then load the application binary. If your boot image that does not require the entire SPI flash,you can use the remaining SPI flash for storing data or look tables, control status info, backup, etc and can access it from your application code after your application has booted from the offset location in the SPI flash. The bootloader and the application code never access the SPI flash at the same time so there is no conflict.

    If you want separate SPI flash for boot and for other usage, you also have the option to use two different flashes at SPI0 and SPI1 OR use a different CS for the flash you want to use with your application code.Hope this helps. Please let us know if there are any follow up questions.

    Regards,

    Rahul

  • 0 in reply to Rahul Prabhu
    Prodigy 30 points

    Thank you very  much for your quicky reply !

    Could you explain code boot sequece when power on for me ? Following is my understanding , is that right ?

    SPI flash which is connected to SPI0 port  store  my applacation code . And I set  pin BOOT[0][1][2][3][7] =10100 by  peripheral pull up/down ciruit .

    when power on , C6745 bootloader check pin voltage only one time and then boot pins are latched by  the bootloader when the device exits reset,  boot mode is alreadly  determined (expample: SPI mode).  And then  SPI0 port can be used for SPI flash , reading or writing flash chip doesn't effect bootloader logic .

    Is that right  or other situation?

  • 0 in reply to jintao Liu
    TI__Guru** 116170 points

    Your understanding is correct.