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Discussion Groups | AT91SAM ARM | Re: 24 bit spi?
For users of the Atmel AT91SAM7 and AT91SAM9 ARM CPU chips. Atmel has taken a new direction by combining on chip flash and ram with the ARM CPU on a single die. This provides low cost devices for small systems using the ARM CPU. This group is to exchange information to help users get started and learn how to use the devices.
Re: 24 bit spi? - Caglar Akyuz - Mar 13 8:57:59 2008
gamerz267 wrote:
> hi,
>
Hi,
> im not really experienced in using a microcontroller and would like to
> know how to used this microcontroller to send 24 bit at a time through
> spi.
> I have set csaat=1 so i can send 3*8bit spi with out the cs line going
> high but i would like to know how to make it high afer the three 8bit
> transfers. Im using PDC to transfer the data.
>
You don't need to use csaat. Just adjust your length to 3, configure in
8 bits and PDC will send 24-bit without toggling CS. You can give delay
after transfer to further force CS at low for an additional period.
After all, if you still need more time for CS staying low then you
should consider csaat.
If you decide using csaat, you should also use lastxfer bit to toggle it
after transfers.
Regards,
Caglar
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
> hi,
>
Hi,
> im not really experienced in using a microcontroller and would like to
> know how to used this microcontroller to send 24 bit at a time through
> spi.
> I have set csaat=1 so i can send 3*8bit spi with out the cs line going
> high but i would like to know how to make it high afer the three 8bit
> transfers. Im using PDC to transfer the data.
>
You don't need to use csaat. Just adjust your length to 3, configure in
8 bits and PDC will send 24-bit without toggling CS. You can give delay
after transfer to further force CS at low for an additional period.
After all, if you still need more time for CS staying low then you
should consider csaat.
If you decide using csaat, you should also use lastxfer bit to toggle it
after transfers.
Regards,
Caglar
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
Re: 24 bit spi? - gamerz267 - Mar 13 18:31:37 2008
--- In A...@yahoogroups.com, Caglar Akyuz wrote:
>
> gamerz267 wrote:
> >
> >
> > hi,
> > Hi,
>
> > im not really experienced in using a microcontroller and would like to
> > know how to used this microcontroller to send 24 bit at a time through
> > spi.
> > I have set csaat=1 so i can send 3*8bit spi with out the cs line going
> > high but i would like to know how to make it high afer the three 8bit
> > transfers. Im using PDC to transfer the data.
> > You don't need to use csaat. Just adjust your length to 3, configure in
> 8 bits and PDC will send 24-bit without toggling CS. You can give delay
> after transfer to further force CS at low for an additional period.
> After all, if you still need more time for CS staying low then you
> should consider csaat.
>
> If you decide using csaat, you should also use lastxfer bit to toggle it
> after transfers.
>
> Regards,
> Caglar
>
Hi i am confused as to what you mean my adjusting the length to be 3.
Is there a register to set for doing that?
------------------------------------
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
>
> gamerz267 wrote:
> >
> >
> > hi,
> > Hi,
>
> > im not really experienced in using a microcontroller and would like to
> > know how to used this microcontroller to send 24 bit at a time through
> > spi.
> > I have set csaat=1 so i can send 3*8bit spi with out the cs line going
> > high but i would like to know how to make it high afer the three 8bit
> > transfers. Im using PDC to transfer the data.
> > You don't need to use csaat. Just adjust your length to 3, configure in
> 8 bits and PDC will send 24-bit without toggling CS. You can give delay
> after transfer to further force CS at low for an additional period.
> After all, if you still need more time for CS staying low then you
> should consider csaat.
>
> If you decide using csaat, you should also use lastxfer bit to toggle it
> after transfers.
>
> Regards,
> Caglar
>
Hi i am confused as to what you mean my adjusting the length to be 3.
Is there a register to set for doing that?
------------------------------------
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
Re: Re: 24 bit spi? - Caglar Akyuz - Mar 14 10:30:42 2008
gamerz267 wrote:
> Hi i am confused as to what you mean my adjusting the length to be 3.
> Is there a register to set for doing that?
>
Hi,
It is the length parameter that you pass to AT91F_SPI_SendFrame and
AT91F_SPI_ReceiveFrame functions. You said you were using PDC, weren't you?
Regards,
Caglar
------------------------------------
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
> Hi i am confused as to what you mean my adjusting the length to be 3.
> Is there a register to set for doing that?
>
Hi,
It is the length parameter that you pass to AT91F_SPI_SendFrame and
AT91F_SPI_ReceiveFrame functions. You said you were using PDC, weren't you?
Regards,
Caglar
------------------------------------
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
Re: 24 bit spi? - gamerz267 - Mar 14 12:23:11 2008
hi,
Yes im using PDC. Thx i'll try that and see if it works
--- In A...@yahoogroups.com, Caglar Akyuz wrote:
>
> gamerz267 wrote:
> > Hi i am confused as to what you mean my adjusting the length to be 3.
> > Is there a register to set for doing that?
> > Hi,
>
> It is the length parameter that you pass to AT91F_SPI_SendFrame and
> AT91F_SPI_ReceiveFrame functions. You said you were using PDC,
weren't you?
>
> Regards,
> Caglar
>
------------------------------------
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
Yes im using PDC. Thx i'll try that and see if it works
--- In A...@yahoogroups.com, Caglar Akyuz
>
> gamerz267 wrote:
> > Hi i am confused as to what you mean my adjusting the length to be 3.
> > Is there a register to set for doing that?
> > Hi,
>
> It is the length parameter that you pass to AT91F_SPI_SendFrame and
> AT91F_SPI_ReceiveFrame functions. You said you were using PDC,
weren't you?
>
> Regards,
> Caglar
>
------------------------------------
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )