wait between bytes

wait between bytes

[Tom]

Hi Everyone,

Does SPI framework have a mechanism to insert a delay between the bytes of a
multi-byte message (transmission or reception).
i.e to handle scenarios where

   1. the master is operating at a high frequency
   2. slave at a lesser frequency
   3. a gpio is used as a slave select
   4. and byte by byte transfer using multiple spi_write is not a choice.

Regards,
Tom
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Re: wait between bytes

[Grant Likely]

On Mon, Mar 14, 2011 at 09:54:50AM +0530, Tom wrote:
> Hi Everyone,
> 
> Does SPI framework have a mechanism to insert a delay between the bytes of a
> multi-byte message (transmission or reception).
> i.e to handle scenarios where
> 
>    1. the master is operating at a high frequency
>    2. slave at a lesser frequency
>    3. a gpio is used as a slave select
>    4. and byte by byte transfer using multiple spi_write is not a choice.

Yes.  See the delay_usec field in struct spi_transfer.

g.


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Re: wait between bytes

[Tom]

Hi,

I thought delay_usec is to create delay between transfers (i.e message
transfers ).
Can it be used to create delay between bytes of a single message transfer?

Regards,
Tom

On Tue, Mar 15, 2011 at 12:41 AM, Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>wrote:

> On Mon, Mar 14, 2011 at 09:54:50AM +0530, Tom wrote:
> > Hi Everyone,
> >
> > Does SPI framework have a mechanism to insert a delay between the bytes
> of a
> > multi-byte message (transmission or reception).
> > i.e to handle scenarios where
> >
> >    1. the master is operating at a high frequency
> >    2. slave at a lesser frequency
> >    3. a gpio is used as a slave select
> >    4. and byte by byte transfer using multiple spi_write is not a choice.
>
> Yes.  See the delay_usec field in struct spi_transfer.
>
> g.
>
>
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A question and answer guide to determining the best fit
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Re: wait between bytes

[Grant Likely]

On Mon, Mar 14, 2011 at 4:10 PM, Tom <tom.spi.devel-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> Hi,
> I thought delay_usec is to create delay between transfers (i.e message
> transfers ).

Between transfers; but a single spi message can contain multiple
transfers without twiddling the cs line.

> Can it be used to create delay between bytes of a single message transfer?

No, you'll have to construct a message of multiple single byte
transfers in that case.

g.

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