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 CCS Technical Support
level shifting between 3.3V and 3.6V

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



Joined: 15 Sep 2003
Posts: 36

View user's profile Send private message

level shifting between 3.3V and 3.6V
PostPosted: Wed Aug 17, 2005 10:50 am     Reply with quote
Hello All,

I would like your help on the following:

I have to connect a 3.6V device to a PIC(PIC18F252) at 3.3V, the manual for the 3.6V device says I can use a diode/resistor level shifting for this.

There is an image that shows a schematic circuit with a 4.7K resistor and a shotky diode, what would be the value for this diode? any shotky diode will do?

Thank you in advance
Peter
eaton2
Guest
PostPosted: Wed Aug 17, 2005 11:25 am     Reply with quote
Without seeing the circuit i can't tell you any particulars but the voltage drop across a schottky is nominally .3V. I would imagine the 4.7K is used as a current limiter
asmallri



Joined: 12 Aug 2004
Posts: 1635
Location: Perth, Australia

View user's profile Send private message Send e-mail Visit poster's website

Re: level shifting between 3.3V and 3.6V
PostPosted: Fri Aug 19, 2005 1:44 am     Reply with quote
runtime wrote:
Hello All,

I would like your help on the following:

I have to connect a 3.6V device to a PIC(PIC18F252) at 3.3V, the manual for the 3.6V device says I can use a diode/resistor level shifting for this.

There is an image that shows a schematic circuit with a 4.7K resistor and a shotky diode, what would be the value for this diode? any shotky diode will do?

Thank you in advance
Peter


I assume you mean you are using a PIC18LF252 not a PIC18F252. The easiest way to solve this would be to run the PIC at 3.6volts. If for some reason you cannot then there are a couple of simple ways you can go about this.

Method one (diode forward volt drop):
Device output to PIC input
Cathode of Shottky diode to PIC
Anode of Shottky diode to Device
4K7 resistor from Cathode to ground

PIC output to device input - directly connected.

Method two (voltage divider method)
Device output to PIC input
390R resistor from Device output to PIC input
4K7 resistor from PIC input to ground

PIC output to device input - directly connected.
_________________
Regards, Andrew

http://www.brushelectronics.com/software
Home of Ethernet, SD card and Encrypted Serial Bootloaders for PICs!!
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