DSPRelated.com
Forums

CLKS pin and McBSP (C5402)

Started by thtraupe May 4, 2005
Hi,
my question is possibly a very simple one:

Where does the CLKS pin get its clock from?

In "Sample Rate Register 2" bit 13 i can choose
to derive the sample rate generator clock from
CPU clock or from CLKS pin. Where CLKS is an
external clock. But where exactly is this external
clock from?
In "Reference Set Volume 5 Enhanced Peripherals"
there is a schematic about clock and frame generaton.
There CLKS pin is an input to the sample rate
generator. Without any hint where it comes from.

Thanks,
Thorsten


hi,

Suppose you want to run the mcbsp/sample rate
generator from a clock other than the CPU clock, you
can feed an external clock at this CLKS pin.
basically, this gives the designer more options.
please see your device data sheet whether the device
you are using has this pin or not. i think some c54x
devices does not have this pin.

regards,
Dileepan.
--- thtraupe <traupe@trau...> wrote:

> Hi,
> my question is possibly a very simple one:
>
> Where does the CLKS pin get its clock from?
>
> In "Sample Rate Register 2" bit 13 i can choose
> to derive the sample rate generator clock from
> CPU clock or from CLKS pin. Where CLKS is an
> external clock. But where exactly is this external
> clock from?
> In "Reference Set Volume 5 Enhanced Peripherals"
> there is a schematic about clock and frame
> generaton.
> There CLKS pin is an input to the sample rate
> generator. Without any hint where it comes from.
>
> Thanks,
> Thorsten >
> c54x-unsubscribe@c54x...


__________________________________________________




Hi Thorsten,

I am not sure this is true for C54x also, but in case of C55x, if the CLKS is configured in external mode, it will be connected to CLKX (external PIN used to feed external CLOCK signal may be 4Mhz or 2Mhz) if you configuring for Tx mode. And it will be connected to CLKR (external PIN, used to feed external CLOCK signal may be 4 or 2Mhz. for 2MB stream) if you are configuring for RX mode.

The CLKS pin is internal to DSP not external.

This is what I understand.

Regards
Prakash Kamliya.