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Booting from a NOR Flash

Nikolay Solovyev
Prodigy 100 points

Hi!
I'm working on custom board based on C5515 DSP. From the data sheet (SPRS645E), the CLKIN can be one of these options: external 11.2896 MHz, 12.0 MHz, or 12.288 MHz or use the internal 32kHz.

I have a question, am i'll be right, if I say what cautious about CLKIN should be given only if boot from SPI, I2C or USB. And if I'll use external 10 MHz oscillator.  Will it successfully boot from NOR flash memory? I plan to use Spansion S29AL032D with access times as fast as 70 ns.

  • 0
    TI__Mastermind 23785 points

    Bootloader set the internal peripheral clock rate based on a known input clock rate. Thus the 3 mentioned rates are used. Any clock rate out of these clock range are not guaranteed.

    Based on these ranges, tjhe max rate is 12.288MHz to generate a >500kHz SPI peripheral clock; a >400kHz I2C peripheral clock and for USB when CLK_SEL = 1, it is multipled by 3.

    So you can pro-rate the SPI & I2C baased on 12.288MHz.

    As for NOR flash, the key requirement is the support of RESET command. Please refer to Bootloader appnote for a list of tested devices.

    Hope this help.

    Regards.