Data about oscillator in internal 4 MHz mode on PIC16F628

Status
Not open for further replies.
G

GrandAlf

Advanced Member level 2
Joined
Mar 9, 2002
Messages
520
Helped
47
Reputation
92
Reaction score
6
Trophy points
1,298
Location
UK
Activity points
4,730
pic16f628 int osc

I would like to migrate from 16F84 to 16C628 for the extra pins available, but am not able to find any data of Osc accuracy or stabilty in internal 4 mhz mode. I tend to use serial comms up to 2400, and am a bit concerned about long term performance. Any experiences most welcome.
 

Re: PIC16F628 Int Osc

I use tons of 628 and if you have a good VCC source and temperature variation is not excessive, internal 4mhz is good for rs232.
 

Re: PIC16F628 Int Osc

Thanks for that, must say it looks pretty good at 5v and room temp. Rather suprising really!, appears that it may be ok even for 9600.
 

Re: PIC16F628 Int Osc

My experience is that you should be very careful with internal RC and RS232 because RS232 normally only tolerates 3% frequency offset especially if you have to receive or transmit longer continuous strings of data.

Short strings (max 6 to 8 characters) were always OK in my applications but whenever I have to deal with RS232 I use a crystal now (they are quite inexpensive today) only a pity if you need absolutely all available pins for other tasks ...

hope this helps
 

Ahh what conflicting opinions, I am of course grateful for both sides of the argument. Looking at the graph, it seems like it is well within 3%. Its always nice to have additional pins, I usually only Tx a max of 16 chars, and could restrict myself to 1200 baud, it looks like it could be ok. Guess its worth a try anyway.
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…