PIC: Dumb question re banksel

Status
Not open for further replies.
A

augustinetez

Active Member
The dumb question using a 16F628 as an example:-

OPTION is in banks 1 & 3 and TMR0 is in banks 0 & 2.

When using banksel for things like OPTION_REG or TMR0 and considering that these exist in two different sets of banks, which bank does it select?

I've been using banksel for these registers for a little while and not knowingly come across a problem doing it - just curious as to possible problems, if any.
 
Sort by date Sort by votes
When I programmed in Asm I kept away from banksel as it always produces two instructions when one or even none are needed. I now realise that it's irrelevant as the processor is so fast (fast enough to use C).
I know you can do it either way but why not use the option instruction (now deprecated) to set the option register?

Mike.
 
Upvote 0 Downvote
A quick simulation (MPLAB SIM) with this code:

Showed RP1 and RP0 bits of STATUS for TMR0 as 00 ( Bank 0) and for OPTION_REG was as 01 (Bank 1). I don't usually use the banksel directive, as I track what bank I am in to minimize switching when practical.
 
Upvote 0 Downvote
Mike, at some stage, I forget if it was an older PIC or a newer enhanced one, I kept getting an error message when trying to use the 'option' instruction, hence I've used option_reg ever since.

JP, thanks for that, answers the question.

I also do my best to group as much code as possible to minimise switching banks.
 
Upvote 0 Downvote
augustinetez said:
Mike, at some stage, I forget if it was an older PIC or a newer enhanced one, I kept getting an error message when trying to use the 'option' instruction, hence I've used option_reg ever since.
Click to expand...
Are you saying that the option instruction no longer works? It was deprecated but I thought it had a few years before being removed.

Mike.
 
Upvote 0 Downvote
Pommie said:
Are you saying that the option instruction no longer works? It was deprecated but I thought it had a few years before being removed.

Mike.
Click to expand...
I thought it had been removed many years ago? - but I can't say I've ever tried it recently?. As far as I'm aware it was 'depreciated' last century?.
 
Upvote 0 Downvote
The 16F628 datasheet mentions it was left in to be compatible with 16C5X chips and should not be used for newer chips.

As to when it actually stopped working I don't know, I'm incapacitated at the moment, so might compile for a few different PICs tomorrow and see where it stops.
 
Upvote 0 Downvote
Status
Not open for further replies.

Similar threads

S
  • Question
Communicating question
Replies
2
Views
2K
Nigel Goodwin
  • Question
Had a PIC fail
Replies
3
Views
2K
schmitt trigger
S
S
  • Question
Pic basic finger print scanner AS608
Replies
7
Views
1K
Nigel Goodwin
  • Question
programming a pic using pickit2/3
2
Replies
39
Views
7K
be80be
G
  • Question
Which PIC programmer to be used?
Replies
1
Views
3K
Nigel Goodwin
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…