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c6745 SPI boot

Anulal SS53
Prodigy 195 points
Other Parts Discussed in Thread: TMS320C6747

Hi,

My processor clock is external 40MHz. Is there any problem to boot my processor in SPI Flash mode? Is there any specific frequency requirement for SPI boot?

Anulal

  • 0
    TI__Expert 5390 points

    Hi Anulal,

    Refer to these documents.

    1. TMS320C674x/OMAP-L1x Processor Serial Peripheral Interface (SPI) User's Guide

    http://focus.ti.com/lit/ug/sprufm4i/sprufm4i.pdf

     

    2. Using the TMS320C6747/45/43 Bootloader

    Page 24; Boot Requirements, Constraints and Default Settings

    http://focus.ti.com/lit/an/sprabb1b/sprabb1b.pdf

     

    Hope this helps.

     

    Best Regards,

    Ankit Agrawal

  • 0 in reply to Ankit Agrawal
    Prodigy 195 points

    HI ankit,

    Thank you for your help.

    I've went through sprabb1b.pdf (Bootloader application note). In Table 4. "Default Clock Configurations for Various Boot Modes" SPI clock frequency for 24MHz input and 25MHz is given. Does it mean that the input clock should be either 24/25 MHz? For other boot modes possible values of clocks are given. 

    Anulal

  • 0 in reply to Anulal SS53
    TI__Genius 17355 points

    Anulal,

    The default clock frequency was intended to be around 1 MHz for SPI memory devices.  Most SPI flash or EEPROM can run much faster than this, but this lower frequency is intended to offer broad compatibility, and users can update the clock settings during the boot, via some AIS commands, to get the clock to run faster.  When using an input clock of 40MHz, the default frequency will scale to be ~1.54 MHz (0.962 *40/25).  That should be fine, but you should double check with your SPI memory datasheet to verify.  If you scale the clock during the boot, make sure you scale using appropriate multipliers and dividers to account for using a 40 MHz input.

    Regards, Daniel