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Discussion Groups | AT91SAM ARM | AT91SAM7 NRST PIN - external reset problem
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.
AT91SAM7 NRST PIN - external reset problem - rolprof - May 2 10:12:38 2008
Hi, is it possible to disable external reset on NRST?
When I try this
*AT91C_RSTC_RCR = AT91C_RSTC_RCR_KEY
| AT91C_RSTC_PROCRST /* (RSTC) Processor Reset */
| AT91C_RSTC_PERRST /* (RSTC) Peripheral Reset */
//| AT91C_RSTC_EXTRST /* (RSTC) External Reset */
I see still a signal drop on NRST.
Thanks in advance
Piotr
------------------------------------
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When I try this
*AT91C_RSTC_RCR = AT91C_RSTC_RCR_KEY
| AT91C_RSTC_PROCRST /* (RSTC) Processor Reset */
| AT91C_RSTC_PERRST /* (RSTC) Peripheral Reset */
//| AT91C_RSTC_EXTRST /* (RSTC) External Reset */
I see still a signal drop on NRST.
Thanks in advance
Piotr
------------------------------------
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
Re: AT91SAM7 NRST PIN - external reset problem - Bernd Walter - May 2 10:56:04 2008
On Wed, Apr 30, 2008 at 11:33:57AM -0000, rolprof wrote:
> Hi, is it possible to disable external reset on NRST?
>
> When I try this
> *AT91C_RSTC_RCR = AT91C_RSTC_RCR_KEY
> | AT91C_RSTC_PROCRST /* (RSTC) Processor Reset */
> | AT91C_RSTC_PERRST /* (RSTC) Peripheral Reset */
> //| AT91C_RSTC_EXTRST /* (RSTC) External Reset */
>
> I see still a signal drop on NRST.
This is to generate a reset to external components if NRST is connected
to a system wide reset.
You want to set URSTEN in AT91C_RSTC_MR to 0 to have the core ignore
NRST pin.
The NRST line is bidirectional, so you can hard reset external
peripherie from software, or the whole system if URSTEN is 1.
--
B.Walter http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.
------------------------------------
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
> Hi, is it possible to disable external reset on NRST?
>
> When I try this
> *AT91C_RSTC_RCR = AT91C_RSTC_RCR_KEY
> | AT91C_RSTC_PROCRST /* (RSTC) Processor Reset */
> | AT91C_RSTC_PERRST /* (RSTC) Peripheral Reset */
> //| AT91C_RSTC_EXTRST /* (RSTC) External Reset */
>
> I see still a signal drop on NRST.
This is to generate a reset to external components if NRST is connected
to a system wide reset.
You want to set URSTEN in AT91C_RSTC_MR to 0 to have the core ignore
NRST pin.
The NRST line is bidirectional, so you can hard reset external
peripherie from software, or the whole system if URSTEN is 1.
--
B.Walter
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.
------------------------------------
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
Re: AT91SAM7 NRST PIN - external reset problem - Bernd Walter - May 2 11:05:31 2008
On Fri, May 02, 2008 at 04:55:50PM +0200, Bernd Walter wrote:
> On Wed, Apr 30, 2008 at 11:33:57AM -0000, rolprof wrote:
> > Hi, is it possible to disable external reset on NRST?
> >
> > When I try this
> > *AT91C_RSTC_RCR = AT91C_RSTC_RCR_KEY
> > | AT91C_RSTC_PROCRST /* (RSTC) Processor Reset */
> > | AT91C_RSTC_PERRST /* (RSTC) Peripheral Reset */
> > //| AT91C_RSTC_EXTRST /* (RSTC) External Reset */
> >
> > I see still a signal drop on NRST.
>
> This is to generate a reset to external components if NRST is connected
> to a system wide reset.
> You want to set URSTEN in AT91C_RSTC_MR to 0 to have the core ignore
> NRST pin.
> The NRST line is bidirectional, so you can hard reset external
> peripherie from software, or the whole system if URSTEN is 1.
Ups - it seems I read yor mail too fast.
You obviously wanted to reset just the integrated components.
Never done that, but from the datasheet (X256) I would expect that
your code should work - no clue why it didn't
Maybe you should read the errata of your specific device.
--
B.Walter http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.
------------------------------------
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
> On Wed, Apr 30, 2008 at 11:33:57AM -0000, rolprof wrote:
> > Hi, is it possible to disable external reset on NRST?
> >
> > When I try this
> > *AT91C_RSTC_RCR = AT91C_RSTC_RCR_KEY
> > | AT91C_RSTC_PROCRST /* (RSTC) Processor Reset */
> > | AT91C_RSTC_PERRST /* (RSTC) Peripheral Reset */
> > //| AT91C_RSTC_EXTRST /* (RSTC) External Reset */
> >
> > I see still a signal drop on NRST.
>
> This is to generate a reset to external components if NRST is connected
> to a system wide reset.
> You want to set URSTEN in AT91C_RSTC_MR to 0 to have the core ignore
> NRST pin.
> The NRST line is bidirectional, so you can hard reset external
> peripherie from software, or the whole system if URSTEN is 1.
Ups - it seems I read yor mail too fast.
You obviously wanted to reset just the integrated components.
Never done that, but from the datasheet (X256) I would expect that
your code should work - no clue why it didn't
Maybe you should read the errata of your specific device.
--
B.Walter
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.
------------------------------------
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )