Control a Radio PLL with a PIC

[RayL113]

Yes, var= variable
bit is one of the placeholders in the larger variable, example
say you want a variable to hold a value as a flag for an event, you could make a bit variable, called . . . FLAGBIT this way FLAGBIT VAR BIT
or you might need several flag bits and do it this way
FLAGBIT VAR BYTE which gives you an 8 bit byte full of FLAGBITS as follows
FLAGBIT.0 lowest bit in the byte
FLAGBIT.1 second bit in the byte
FLAGBIT.2 third " " " "
FLAGBIT.3 . . .
FLAGBIT.4 . . . all the way to FLAGBIT.7 , FLAGBIT.7 being the highest order bit in the byte variable
which is to say you can address every bit of your variable individually.
Byte = %00000000 will hold 0 to 255 in decimal
word = %00000000 00000000 will hold 0 to 65535 in decimal
LONG = %00000000 00000000 00000000 00000000 which is 4294967295 but I think (I am not sure of this) only allows 1/2 that much on each side of zero -2147483647 0 2147483647

Notice the way I have written the binary expression %00000000 this is the appropriate syntax for P Basic Pro, other compilers may use different "punctuation" and you will see "BIG ENDIAN" and LITTLE ENDIAN" usage and all that means is which end of the group of zeros is the least significant bit, the Left or the Right.

You will see different ways of displaying hex as well, in PBP we use $00 whereas in C you might see something like 0h00

Thanks that helps alot. Yes I had noticed the % in front of what looked like binary expressions but hadn't noticed the $ in front of hex expressions. Can you still use the "b and h" in PCB? In case I forget and use the asm expression?

[mackrackit]

Can you still use the "b and h" in PCB?

Nope.
From the manual.
4.8. Numeric Constants

PBP allows numeric constants to be defined in the three bases: decimal, binary and hexadecimal. Binary values are defined using the prefix '%' and hexadecimal values using the prefix '$'. Decimal values are the default and require no prefix.

100 ' Decimal value 100
%100 ' Binary value for decimal 4
$100 ' Hexadecimal value for decimal 256

[RayL113]

What if I want to use a cb channel switch instead of an encoder? The first four pins have a logical progression of 0000 to 1111. Couldn't I use this like a Gray code encoder? Count increase would equal up and count decrease would equal down. What do you think?

[cncmachineguy]

You can use that, you can use the thing you already have, its up to you. They both CAN work. With the CB switch you will only get 16 changes per full revolution. If this is enough then use it. It will prolly still have noisey output so de-bouncing will still be neccessary. Now if you can get this, I have used many, they work really well.

Let us know how you are getting along on this project. Have you blinked a LED on port A yet?

[Archangel]

Search here . . .

http://www.mouser.com/Electromechani...ers/_/N-39xfc/

Seriously Cheap !

[RayL113]

You can use that, you can use the thing you already have, its up to you. They both CAN work. With the CB switch you will only get 16 changes per full revolution. If this is enough then use it. It will prolly still have noisey output so de-bouncing will still be neccessary. Now if you can get this, I have used many, they work really well.

Let us know how you are getting along on this project. Have you blinked a LED on port A yet?

I think I'm going to try to use the channel selector approach. Using RE1 thru RE4 as the inputs. I read in the manual that there is a command that will sample the designated pins and store the result in a register of my chosing. The problem I am having trouble sorting out in my head is what should I do when the count goes back to 0000 after 1111 and vice versa. And still have the count continue up or down. Is there some way to like have a loop restart when this limit is reached?
Just messing with it as time allows. So not much progress. Still learnig the PBP commands and uses. And yes, got LED's blinking like crazy using machine code, but haven't tried it wih PBP yet.
Thanks for the helps Guys!

[cncmachineguy]

well let me say I think its the more complicated way, but hey that makes it more fun. I would guess you will have to read the count on the selector, compare it to the last count, If it is higher, add 1 to the freq, if its less subtract. To cross the zero, you will have 2 choices when at 0 of at $F. from o you will go to 1 or $F, and from $F you will go to 0 or $E. So just check for that when you get to those counts.

I would think you will have to really spin the selector VERY fast to miss any counts, so I would start with that scheme and see how it works. Don't forget you may need to de-bounce the inputs.

[RayL113]

Thanks Bert. Should I use the IF...THEN string? Something like this;
Start
PEEK CHSEL CHSELVAR
IF CHSEL = 0000 THEN CHECK0
IF CHSEL = 1111 THEN CHECK1
ELSE LOOP

LOOP
PEEK CHSEL CHSELVAR
If CHSEL > CHSELVAR Then UP
Else
PEEK CHSEL CHSELVAR
IF CHSEL < CHSELVAR Then DOWN
Else
GOTO Start

UP
PLLDATA = PLLDATA +1
MOVLF PLLDATA PLLDATAOUT
GOTO Start

DOWN
PLLDATA = PLLDATA -1
MOVLF PLLDATA PLLDATAOUT
GOTO Start

CHECK0
IF CHVAR = 0001 THEN UP
IF CHVAR = 1111 THEN DOWN
ELSE LOOP

CHECK1
IF CHVAR = 0000 THEN UP
IF CHVAR = 1110 THEN DOWN
ELSE LOOP

Of course I didn't include all the defines. Am I on the right track?