RC5 [Manchester] Decoding ....Does this Work ??

[chriss2000]

#include <16f876.h>
#Device ICD=TRUE
#use delay(clock=4000000)
#bit T0IF=0xB.2
#bit INTF=0xB.1
#use rs232(BAUD=9600, xmit=pin_c6, rcv=pin_c7)

int newbit=0,ready=0,offset=1,i=0;
long count=0,code=0,abtast=75;

void main()
{
set_tris_A(0xFF);
set_tris_B(0xFF);
set_tris_C(0x00);
enable_interrupts(global); enable_interrupts(int_ext); ext_int_edge(H_TO_L);
while(1) {
while(ready==1)
{
if(i<14)
{
count=get_timer0();
if(count>=abtast)
{
newbit=input(Pin_A0);
code=code|newbit;
code<<=code;
abtast=abtast+111;
printf("\%c",code);
}
i++;
ready=0;
}
}
}
}

#int_ext
isr() {
disable_interrupts(int_ext); setup_timer_0(RTCC_DIV_16|RTCC_Internal);
set_timer0(0);
ready=1;
}
___________________________
This message was ported from CCS's old forum
Original Post ID: 10682

[Hans Wedemeyer]

no...!
Not sure about your actual code, but these items are critical
You did not initialize Timer 0.
Do this BEFORE you release the global interrupt.

void main()
{
set_tris_A(0xFF);
set_tris_B(0xFF);
set_tris_C(0x00);

setup_timer_0(RTCC_DIV_16|RTCC_Internal);
ext_int_edge(H_TO_L);
enable_interrupts(int_ext);

enable_interrupts(global); // let it rip

while(1)
{
// your code here
}
}

No need to stop interrupts in int_ext just set timer0() and the flag
#int_ext
isr() {
{
set_timer0(0);
ready=1;
}
I'm not sure what your need is when setting Timer0 to zero,
I expect you are trying to measure something...If the external input is what's being measured then I don;t see how it will work !

If you Get_Timer0() before resetting it, you will be able to measure the time between the last interrupt and the current interrupt. Assuming Timer0 does not overflow. !

int DeltaTime=0; // some global var.

#int_ext
isr() {
{
DeltaTime = Get_Timer0(); / time since last event
set_timer0(0);// start measuring next event
ready=1;
}
___________________________
This message was ported from CCS's old forum
Original Post ID: 10685

[chriss2000]

#include <16f876.h>
#Device ICD=TRUE
#use delay(clock=4000000)
#bit T0IF=0xB.2
#bit INTF=0xB.1
#use rs232(BAUD=9600, xmit=pin_c6, rcv=pin_c7)

int newbit=0,flag=0,offset=1,i=0;
long count=0,code=0,abtast=75;

#int_ext //allow ext interrupt
isr() //Interrupt Service Routine
{
disable_interrupts(int_ext); //disable interrupt on Pin B0 [until the next signal
set_timer0(0); //Set Timer 0 to zero
flag=1; //Set Interruptflag to 1
}

void main()
{
set_tris_A(0xFF);
set_tris_B(0xFF);
set_tris_C(0x00);
setup_timer_0(RTCC_DIV_16|RTCC_Internal); //Timer 0 Setup, counts up with 62,5kHz
//Teilung: When the counter has the value 1, 16us have left

enable_interrupts(int_ext); //Allow ext Interrupt on Rb0
enable_interrupts(global); //Allow Global Interrupt
ext_int_edge(H_TO_L); //Wait for falling edge--> then jump to Interrupt Service Routine
while(1) //As long as True -->Make Main
{
while(flag=1)
{
if(i<14) //14 Bit Code-->scan 14 times
{
count=get_timer0(); //Get counter time
if(count>=abtast) //If counter time is greater than the value were i want to scan my signal-->scan the Pin A0
{
newbit=input(Pin_A0); //get the bit value of Pin A0
code=code|newbit;
code<<1; //Shift the input values in my integer
abtast=abtast+111; //count up my scan value

}
i++;
}

delay_ms(80); //80ms delay to wait for the beginning of the next signal
enable_interrupts(int_ext); //allow ext Interrupt on Pin B0
flag=0; //Set The Interrupt Flag to Zero to get out of the cycle
abtast=75; //The Timer Value 75 is the same as 1,2 ms and i need that time to scan my bit in the 3/4 bit size
i=0;
}
}
}
___________________________
This message was ported from CCS's old forum
Original Post ID: 10728