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

Implementing a PIC16F877A onto a circuit board

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



Joined: 18 Nov 2006
Posts: 4

View user's profile Send private message

Implementing a PIC16F877A onto a circuit board
PostPosted: Sat Nov 18, 2006 4:57 pm     Reply with quote

Hi,
I am currently using the PIC16F877A with the CCS Software Prototyping Board in one of my classes. I would like to use the PIC without the board but I am confused to which pins have to be wired.

I am using the following pins: RA0 to read in a swtich
RA1 to read in a sensor ouput
C1 digital ouput to an h-bridge
C2 digital output to an h-bridge

I was wondering do both of the VDD and Vss pins have to be wired, and I don't plan on having a reset option....do I still need to wire the MCLR pin?

Also the datasheet lists a maximum current into the VDD pin....I was wondering what is the minimum current that can go into the VDD pin.
Thanks
Randy
Mark



Joined: 07 Sep 2003
Posts: 2838
Location: Atlanta, GA

View user's profile Send private message Send e-mail

PostPosted: Sat Nov 18, 2006 7:03 pm     Reply with quote

Yes and Yes. The minimum current depends on many factors, speed, driving current, preipherals, ect...
Rando



Joined: 18 Nov 2006
Posts: 4

View user's profile Send private message

PostPosted: Sat Nov 18, 2006 7:19 pm     Reply with quote

Thanks for the reply Mark... Just to get this straight I'd need the 2 VDD pins, the 2 Vss pins, the 2 input pins, the 2 output pins and the MCLR pin.
Also to wire the MCLR pin just follow the recommended MCLR circuit in the datasheet? ( p.148 figure 14-5).

This might also seem like a dumb question but as I said I've only used the chip on the protoboard........ do u need an external Socketed Oscillator?...or is that only needed if you have a timer in your program.

Thanks,
Randy
jecottrell



Joined: 16 Jan 2005
Posts: 559
Location: Tucson, AZ

View user's profile Send private message

PostPosted: Sat Nov 18, 2006 9:58 pm     Reply with quote

Quote:
Just to get this straight I'd need the 2 VDD pins, the 2 Vss pins, the 2 input pins, the 2 output pins and the MCLR pin.


That is correct. MCLR can simply be pulled up to Vdd through a 47K resistor.

Quote:
do u need an external Socketed Oscillator?...or is that only needed if you have a timer in your program.


You need some form of oscillator. Your choices are listed in 14.2. A crystal with the associated capacitors is the simplest (see table 14-2.) The resistor usually isn't necessary.

You should also have a 0.1uF cap on each of the Vdd pins as close to the pin as you can get. This will save a lot of grief later on.

John
Rando



Joined: 18 Nov 2006
Posts: 4

View user's profile Send private message

PostPosted: Sat Nov 18, 2006 10:25 pm     Reply with quote

Thank you for the quick response. I will give that a try
jma_1



Joined: 08 Feb 2005
Posts: 147
Location: Wisconsin

View user's profile Send private message

PostPosted: Sun Nov 19, 2006 10:32 am     Reply with quote

Greetings,

If you do not want to use an external oscillator, pick a different microprocessor. Some of the 18 series chips can run with the internal oscillator as the clock source.

Cheers,
JMA
Rando



Joined: 18 Nov 2006
Posts: 4

View user's profile Send private message

PostPosted: Sun Nov 19, 2006 10:40 am     Reply with quote

Thanks I will keep that in mind for the future. However, the school supplies the PIC16F877A and I'm just getting used to it ....so I do not think I will change the PIC.
Randy
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