Accessing Pic SFRs as an array.

P

Pommie

Well-Known Member

Most Helpful Member

• May 11, 2022

• #1

I've been playing around with a pic again and needed to access the PPS SFRs located sequentially in memory at 0xF18. The first one is RB0PPS and to access them as an array you can do,
((unsigned char *)&RB0PPS)[7]=0x01;
This would write 1 to RB7PPS. This would enable the CLC1 output on RB7.

Well, I found it useful.

Mike.

 

Ian Rogers

User Extraordinaire

Forum Supporter

Most Helpful Member

• May 11, 2022

• #2

I tell you what.... I have just repositioned SPI 1, 2 and 3 on a pic24... The PPS is a bit of a mine field..

I have 31 RP pins trying to fathom them out is a task!! All done though...

 

P

Pommie

Well-Known Member

Most Helpful Member

• May 11, 2022

• #3

PPS is indeed a minefield. I tend to move just the bit I need (input or output) and the above was to move CCP1's output to RB0 through RB7.

Mike.

 

rjenkinsgb

Well-Known Member

Most Helpful Member

• May 11, 2022

• #4

Yet another reason I like the CCS compiler - just tell it what peripheral pin allocations you want & it sets the appropriate registers:

C:

#PIN_SELECT U1TX = PIN_B4
#PIN_SELECT U1RX = PIN_B15

 

Ian Rogers

User Extraordinaire

Forum Supporter

Most Helpful Member

• May 11, 2022

• #5

On the pic24 they have a locking mechanism for the PPS in the OSCCON reg... BUT!! they have a write enable sequence for the OSCCON register... AARRGGHH..

But I have it sussed

 

P

Pommie

Well-Known Member

Most Helpful Member

• May 11, 2022

• #6

rjenkinsgb said:

Yet another reason I like the CCS compiler - just tell it what peripheral pin allocations you want & it sets the appropriate registers:

C:

#PIN_SELECT U1TX = PIN_B4
#PIN_SELECT U1RX = PIN_B15

Click to expand...

Yes, the code configurator will do that but accessing them as an array is much more flexible.

Mike.