Reading pins on port b to a variable.

[Paul H]

Hi I have a rotary encoder connected to pins b2, b3 on
a f873 pic.

I define the pins as follows...

#define Encoder pin_b2, Pin_b3
//< global variables >
int old;
int new;
int count;

In main I set up my direction register so that pins
b2, b3 are inputs

void main(Void)
{
set_tris_b(0b00001111);

???? How do I place the value of "Encoder" into the variable old.

Also is my method of defining the pins b2, b3 valid or should
it be done some other way.

I tried using input(encoder), old)); and varients of same
but cant seem to get it to work.

Thanks....Paul.




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This message was ported from CCS's old forum
Original Post ID: 1521

[ajt]

Hi Paul

I recently did a test program just like this. The following may not be the most elegant way but it works (I'm new and learning this stuff as well)

This is not a full program but just the salient points. Phase A of the encoder is on B0 and phase B is on B4. LEDs are on the C0 and C1 pins.

#INCLUDE <16F877.H>
... etc.
signed int16 count;

#INT_EXT
void isr() {
output_high(PIN_C1);
output_bit(PIN_C0, input(PIN_B4));
if (input(PIN_B4) == 1)
++count;
else --count;
printf("Count = \%04ld \r",count);
output_low(PIN_C1);
}

main() {
count = 0;
set_tris_b(0xFF);
ext_int_edge(0,L_TO_H);
enable_interrupts(INT_EXT);
enable_interrupts(GLOBAL);
... etc.


:=Hi I have a rotary encoder connected to pins b2, b3 on
:=a f873 pic.
:=
:=I define the pins as follows...
:=
:=#define Encoder pin_b2, Pin_b3
:=//< global variables >
:=int old;
:=int new;
:=int count;
:=
:=In main I set up my direction register so that pins
:=b2, b3 are inputs
:=
:=void main(Void)
:={
:=set_tris_b(0b00001111);
:=
:=???? How do I place the value of "Encoder" into the variable old.
:=
:=Also is my method of defining the pins b2, b3 valid or should
:=it be done some other way.
:=
:=I tried using input(encoder), old)); and varients of same
:=but cant seem to get it to work.
:=
:=Thanks....Paul.
:=
:=
:=
:=
___________________________
This message was ported from CCS's old forum
Original Post ID: 1523
_________________
Al Testani

[Tomi]

:=???? How do I place the value of "Encoder" into the variable old.
:=Also is my method of defining the pins b2, b3 valid or should
:=it be done some other way.
An example for correct usage of #define:
#define Encoder ((*0x06 >> 2) & 0x03) // shift b2-b3 to b0-b1 and mask it
......
char a;
a = Encoder; // possible values: 0,1,2,3
oldval = Encoder;
___________________________
This message was ported from CCS's old forum
Original Post ID: 1524

[Paul H]

Hi tomi & ajt..These little rotary encoders are a neat
device but a pain to implement "well for a newbe like myself"

I found a good link to a appnote that shows how to implement
them, check it out below. The appnote is for the pic, but the
code is in asm.

Thanks for the help.. When I get something that works I will
post the source as it might help other members of the group.
I will try and implement tmro 0 as a method of checking the
encoder.

Thanks guys...Paul.
___________________________
This message was ported from CCS's old forum
Original Post ID: 1534