CCS C Software and Maintenance Offers
FAQFAQ   FAQForum Help   FAQOfficial CCS Support   SearchSearch  RegisterRegister 

ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

CCS does not monitor this forum on a regular basis.

Please do not post bug reports on this forum. Send them to support@ccsinfo.com
Brownout setting

 
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion
View previous topic :: View next topic  
Author Message
FRED_SUN



Joined: 28 Jul 2008
Posts: 7

View user's profile Send private message

Brownout setting
PostPosted: Mon Jul 28, 2008 2:38 pm     Reply with quote
Hi,
I need to set BROWNOUT in order to make sure it will work fine when I change battery. But in sleep mode, BROWNOUT cost about 40 uAmp, how can I set NOBROWNOUT before it go to sleep, and recover it after the sleep ?
Thanks
Fred
Ttelmah
Guest
PostPosted: Mon Jul 28, 2008 2:48 pm     Reply with quote
You probably can't.
Tell us what chip?.
On most, the brownout setting, is a fuse only setting, and cannot be changed, once the chip is running.
Turning brownout 'off' in sleep, rather spoils the point of it, since brownout failures are just as likely to happen when you are asleep...
Alternative is to attach an external brownout circuit to the MCLR pin, and have this switchable.

Best Wishes
FRED_SUN



Joined: 28 Jul 2008
Posts: 7

View user's profile Send private message

PostPosted: Mon Jul 28, 2008 4:55 pm     Reply with quote
Ttelmah wrote:
You probably can't.
Tell us what chip?.
On most, the brownout setting, is a fuse only setting, and cannot be changed, once the chip is running.
Turning brownout 'off' in sleep, rather spoils the point of it, since brownout failures are just as likely to happen when you are asleep...
Alternative is to attach an external brownout circuit to the MCLR pin, and have this switchable.

Best Wishes


Thanks,
The chip I am using is 18f2525, and if I attach an external brownout circuit to the MCLR pin, it also use current, in my application, I can not put in any switch.
Thanks.
Fred
libor



Joined: 14 Dec 2004
Posts: 288
Location: Hungary

View user's profile Send private message

PostPosted: Tue Jul 29, 2008 6:48 am     Reply with quote
You might want to check the new K-series chips (like 18F25K20) they have the brownout reset under software control with many options, like automatically disabling it when sleeping, etc.

...though it would not give a solution to your problem. Anyway the K-series are more optimized for the low-power operation.
Ttelmah
Guest
PostPosted: Tue Jul 29, 2008 9:55 am     Reply with quote
If you can switch off the internal brownout, you can switch off the external brownout. I am talking about a solid state switch (MOSFET), not some damn great mechanical thing!....

Best Wishes
FRED_SUN



Joined: 28 Jul 2008
Posts: 7

View user's profile Send private message

PostPosted: Tue Jul 29, 2008 10:46 am     Reply with quote
libor wrote:
You might want to check the new K-series chips (like 18F25K20) they have the brownout reset under software control with many options, like automatically disabling it when sleeping, etc.

...though it would not give a solution to your problem. Anyway the K-series are more optimized for the low-power operation.


Thanks!
I checked out 18f25k20, it use 3.3v power suply, but in my application, I need to drive 5v display.
I talked with microchip, they tell me I can change the CONFIGURATION REGISTER 23, low 2 (300002h).
Can I use "write_configuration_memory (dataptr, count) " to do it?
the function says it Erases all fuses and writes count bytes from the dataptr to the configuration memory. what is the meaning? Can I use it to change the brownout setting only or I need to redo all the Configuration?

Thanks!
Fred
Display posts from previous:   
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group