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Discussion Groups | Rabbit-Semi | Why Shadow register used instead of SFR
This is a group for folks designing and programming embedded systems using the Rabbit Semiconductor C-programmable microcontroller. Rabbit Semi is a spin-off from Z-World who makes a variety of embedded modules and tools. This group is not affiliated with either Rabbit or Z-World, but is a user forum for sharing ideas, asking questions, flaunting knowledge, and other typical user group stuff. The Rabbit is a powerful uC, supported by a full-featured C-compiler.
Why Shadow register used instead of SFR - kapil_chittewan - Jul 16 4:51:29 2008
Hi Folks,
Can anyone tell me why shadow registers are used for SFRs. If I am not
wrong, It been used for debug purpose only.
Thanks
Kaps
------------------------------------
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Can anyone tell me why shadow registers are used for SFRs. If I am not
wrong, It been used for debug purpose only.
Thanks
Kaps
------------------------------------
(You need to be a member of rabbit-semi -- send a blank email to rabbit-semi-subscribe@yahoogroups.com )
Re: Why Shadow register used instead of SFR - Scott Henion - Jul 16 5:58:27 2008
kapil_chittewan wrote:
> Hi Folks,
>
> Can anyone tell me why shadow registers are used for SFRs. If I am not
> wrong, It been used for debug purpose only.
>
>
Most of the registers are write-only. So you can not read them back if
you need to change bits. That is why the shadow regsa re eneeded.
--
------------------------------------------
| Scott G. Henion| s...@shdesigns.org |
| Consultant | Stone Mountain, GA |
| SHDesigns http://www.shdesigns.org |
------------------------------------------
Rabbit libs: http://www.shdesigns.org/rabbit/
today's fortune
You have read that Muad'Dib had no playmates his own age on Caladan. The
dangers were too great. But Muad'Dib did have wonderful companion-teachers.
There was Gurney Halleck, the troubadour-warrior. You will sing some of
Gurney's songs, as you read along in this book. There was Thufir Hawat, the old
Mentat Master of Assassins, who struck fear even into the heart of the Padishah
Emperor. There were Duncan Idaho, the Swordmaster of the Ginaz; Dr. Wellington
Yueh, a name black in treachery but bright in knowledge; the Lady Jessica, who
guided her son in the Bene Gesserit Way, and -- of course -- the Duke Leto,
whose qualities as a father have long been overlooked.
-- from "A Child's History of Muad'Dib" by the Princess Irulan
------------------------------------
(You need to be a member of rabbit-semi -- send a blank email to rabbit-semi-subscribe@yahoogroups.com )
> Hi Folks,
>
> Can anyone tell me why shadow registers are used for SFRs. If I am not
> wrong, It been used for debug purpose only.
>
>
Most of the registers are write-only. So you can not read them back if
you need to change bits. That is why the shadow regsa re eneeded.
--
------------------------------------------
| Scott G. Henion| s...@shdesigns.org |
| Consultant | Stone Mountain, GA |
| SHDesigns http://www.shdesigns.org |
------------------------------------------
Rabbit libs: http://www.shdesigns.org/rabbit/
today's fortune
You have read that Muad'Dib had no playmates his own age on Caladan. The
dangers were too great. But Muad'Dib did have wonderful companion-teachers.
There was Gurney Halleck, the troubadour-warrior. You will sing some of
Gurney's songs, as you read along in this book. There was Thufir Hawat, the old
Mentat Master of Assassins, who struck fear even into the heart of the Padishah
Emperor. There were Duncan Idaho, the Swordmaster of the Ginaz; Dr. Wellington
Yueh, a name black in treachery but bright in knowledge; the Lady Jessica, who
guided her son in the Bene Gesserit Way, and -- of course -- the Duke Leto,
whose qualities as a father have long been overlooked.
-- from "A Child's History of Muad'Dib" by the Princess Irulan
------------------------------------
(You need to be a member of rabbit-semi -- send a blank email to rabbit-semi-subscribe@yahoogroups.com )