DAC parameters for C5505

Tommy Hosman

I am wanting to attach a DAC to the C5505 chip and I just want to make sure I am getting things straight. If I was wanting to use SPI port for a 5MHz DAC with 12 bits, I would not be able to do so. This is because the SPI's clock runs its fastest at 25MHz which could handle 5 bits. Is this all correct?

over 15 years ago

0 Steve Tsang over 15 years ago

TI__Mastermind 23785 points

When running the DSP system clock at 100MHz, the SPI_CLK would be at 25MHz.. The character length can be set up to 32 bits via CLEN bits in SPICMD2 register.

0 Tommy Hosman over 15 years ago in reply to Steve Tsang

Intellectual 260 points

I just want to clarify that that is 32 bits per clock cycle of the spi? Thanks for the reply

0 Steve Tsang over 15 years ago in reply to Tommy Hosman

TI__Mastermind 23785 points

Tommy,

The 32 bits are not transmitted in one single clock cycle. If you refer to the figures on page 13 of the SPI User's Guide, SPRUF03, the bits are transmitted in serial. Hope this helps.

Steve

0 Tommy Hosman over 15 years ago in reply to Steve Tsang

Intellectual 260 points

Thank you for the help. This clarifies what I thought was true. Thanks again.

0 Steve Tsang over 15 years ago in reply to Tommy Hosman

TI__Mastermind 23785 points

Tommy,

Glad to help. If this close your question, could you help by closing it with setting the Verified Answer button?

Thanks,

Steve

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DAC parameters for C5505