c5535 ezdsp : C5535 running at 12.288 MHz as well as FTDI

Nicolas Boulot

Hello,

I need to run the C5535 on the C5535 ezDSP board at 12.288 MHz using the CLKIn input. So I have 2 options :

1) replace the original 12 MHz oscillator with my 12.288 MHz source : the FT2232HL (XDS100-V2 INTERFACE) will run at 12.288 MHz rather than 12.000 MHz => is it a problem ?

2) keep the origianl 12 MHz oscillator for the FT2232HL (XDS100-V2 INTERFACE), and tie my external 12.288 MHz oscillator to C5535 CLKIN. In that case, both IC won't run at the same speed => is it a problem ?

Thanks for your comments

Nicolas

over 12 years ago

0 Mark M over 12 years ago

TI__Mastermind 30110 points

Hi Nicolas,

FT2232HL requires 12MHz ± 0.003% for its USB communication

See 6.3 Oscillator Configuration in http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT2232H.pdf

I would provide 12.288MHz to CLKIN, as described in #2 - remove R38 and wire the clock to R38 or R34.

Why do you need to do this? Are you using the C5535 as I2S Master?

Hope this helps,
Mark

0 Nicolas Boulot over 12 years ago in reply to Mark M

Intellectual 330 points

Hi Mark,

Thanks for the comment.

For a specific application, I need the C5535 running at 98.304 MHz (8x12.288 MHz).

Using a 12 MHz input clock, I can not achieve an exact 98.304 MHz CPU Clock.

Nicolas

Processors

Processors forum

c5535 ezdsp : C5535 running at 12.288 MHz as well as FTDI