manchester decode

[temtronic]

sigh, I've been so focused on the 'data' aspect, I forgot about the 'sync' requirement.
Of course it'll never,ever work..

It needs a total rewrite, back to the beginning, literally.....

[bulut_01]

God damn it, I'm running out of hope on this issue. If you could help me, I'd be grateful.

[PrinceNai]

I believe that is the reason for that lonely zero at the beginning, which is not part of the actual dala sent out.

[temtronic]

OK, start fresh.

Create a program that SEES the 'preamble or sync or whatever you want to call that series of 8 pulses that are 2.5 ms wide.
My idea is to measure a pulse, if 2.5ms wide, increment a counter,loop looking for more.....
When you have 8, delay for say 1ms(?), then flash an LED,
Your logic analyzer should show the 'remote ' data as well as the LED status.

You need to do this before trying to read/decode the buttons.
there are 1,000s of hit for 'measuring pulse width with PIC', check code library here,could be something close to what you need.

[bulut_01]

Thank you masters, I will do what you said and publish it here

[bulut_01]

As you said, I did the preamble reading part and tested it. The preamble decode part works. 7 bytes of preamble data are taken, then the header part is taken, then the Manchester decode part is started, but in this way the Manchester decode part does not work.

[temtronic]

OK had a quick look...
and I think the program needs to do the following..

main()
loop starts here
enable CCP3 interrupt
now..... CCP3 ISR waits for 7 pulses ,sets flag 'sync found'
disable CCP3 interrupt //could be 2nd last line in CCP3 ISR
might need a delay(1ms) here....//a pause between sync ...and ... data
enable timer0 interrupt// could be last line in CCP3 ISR
now... timer 0 captures ' 7 bytes of data'
disable timer0 interrupt // could be last line in Timer0 ISR
parse buffer B[] to get key pressed
send information to PC terminal program

loop ends here


The data in B[] should look like the actual bytes in the logic analyzer

You have to disable the CCP3 interrupt when 'sync' is found , otherwise real 'data' will cause CCP3 interrupts.Same for the Timer0 ISR. 'clearing' an interrupt only 'resets' the flag that an interrupt occoured. 'disable' prevents all incoming pulses on the input pin from doing 'anything'.

curious why the 1600 baud rate for the RS232 to PC ?

You're making great progress !! It's best to learn by doing, that way you'll understand WHAT is happening better.

[bulut_01]

[bulut_01]

I am sure about the 4 settings here why the code is not working

[temtronic]

here's the logic I'm thinking you need..

while(true){
///////////////////////////////////////////////////////////////////////////////
enable_interrupts( INT_CCP3); // this aloows PIC to 'see' the sync'
if(works==1) { //got 'sync' !!
disable_interrupts(INT_CCP3); //stop 'data' from triggering the 'sync' ISR
enable_interrupt( Timer0); // now get 'data' bits
}
if(ready==1) { //got 'data' !!
disable_interrupts(Timer0);
ready_(); //display 'data' buffer B[] contents
}
if(XTMR < 512){
XTMR=0;
}
//
init_receiver();
delay_ms(50); //just a small main loop delay.
}


in main()
1st you setup registers and stuff but do NOT enable the interrupts
in a loop.....
you enable the CCP3 ISR and it gets 'sync'
then disable CCP3 interrupt ,
then enable the timer0 ISR ,and collect the 'data'
then disable Timer0 interrupt.
then send 'data' to PC screen
than small delay
then go back to top of loop

It does compile but I can't test. it was also very hard for me to see the screen, old age,light fonts, sigh.

Think of the program 'flow' like a 'high security' building double door entrance

you unlock the 1st door ( enable the 'sync' interrupt' )
open and enter ( 'sync' bytes found ! )
lock the 1st door (prevent following bytes in )
unlock 2nd door( enable timer0 interrupt
open and enter house ('data' bytes found ! )
lock 2nd door ( disable timer0 )
show data ( send 'data' to PC )

I may not have it exact , hope you can understand the 'flow' of operations...
You're really close though !!!

[bulut_01]

[temtronic]

Sorry, I can't help you with any PROTEUS projects, as it's well known that it does not actually work properly. One glaring error in the picture, have a look at D1, the red LED.

[bulut_01]

[temtronic]

query.
Are you using real hardware or is this a Proteus Simulation ?

[bulut_01]

I am using real hardware. I see real circuit values ​​by putting putc in some places. Whatever I see in Proteus, I see the same value in the real circuit. This timer0 overflow decode needs to have a 72 ms cycle, is that correct?