Help with serial communication

[PCM programmer]

I didn't look closely at your code, but I have these comments:

[Ttelmah]

And particularly, 'enable_interrupts(GLOBAL)', must _never_ be used inside a PIC interrupt handler. It is _lethal_ to the code, to do so.
The problem here is that the PIC does not support interrupts interrupting themselves. There is quite a bit more to the interrupt handler that happens after you return from the code you have written. As PCM programmer says, the PIC _hardware_ re-enables the interrupts when you actually return from the handling code. By enabling them earlier, you can cause interrupts to be acccepted before you return, which _will_ result in data being corrupted, killing the program.

Seperately though think how often characters may arrive, and how long your loop takes. Make your loop faster than the expected time between characters, and wait for one to arrive. Currently, the loop in your slave, takes 400mSec if 'T' has been seen, and 440mSec, if not. The 'master' is sending a character every 240mSec, so how can the slave expect to keep up?. This in fact makes the above problem _certain_ to cause problems, since two characters can be waiting in the hardware buffers, there will be a second interrupt when you enable the interrupts inside the handler, and a crash will result...

Best Wishes

[nuno12345]

Thank you both

Ok, I will remove those lines from my code.

PCM both pics share the same supply.

I fixed the problem in a simulator, I'm using 16F88 and 16F628A, I tested the transmitter code on both pics, in 16F88 it was working but it wasn't in 16F628A, I realized that if I changed the baud rate to half it was working, so I thought in the clock, I changed pic's 16F628A clock to 4M and it worked .

Now I got another problem, a bit off topic but, I don't know why but it seems some of my PIC's stop working randomly, they won't even start.

In 16F88 I can't even run the simplest code, the PIC won't start, but its as simple as leave it alone or sometimes reprogram it with the same code and it works :/.
Also another problem with this PIC is that the programmer only detects it once, but I cant program it, if I "ask" the programmer to identify the PIC again it says UNKNOWN

In 12F675 if I disconnect and reconnect the supply, sometimes it runs. Also it seems to run with different clocks even if its the same exact program, the test I did was just to make a LED flash and sometimes it flashes faster than others.

16F628A does not have any problem at all, it starts first time.

Fuses maybe?

[PCM programmer]

1. Enable the Brownout fuse.

2. Enable the Power-Up Timer fuse (PUT).

3. If you have MCLR enabled, make sure you have a pull-up resistor on it.
Use 10K for Microchip ICD2, or 47K for CCS ICD-U40.

4. Make sure you have a 100 nF ceramic capacitor between each Vdd pin
on the PIC and ground. Place the cap very close to the chip.

5. Make sure you have a clean, solid, correct Vdd voltage for the PIC.

6. If using a crystal, make sure you have the correct value of caps
installed in the crystal circuit. (22 pf will work for 4 MHz to 20 MHz).

[nuno12345]

Looks like the fuse PUT is doing something to the PIC.

my code:

[PCM programmer]

What's your Vdd voltage on the PIC ? What device is supplying it ?
Is it a bench power supply ? Or a voltage regulator I.C. ? Or a
debugger ?

I notice you still have the NOBROWNOUT fuse.

You should add BROWNOUT, and do everything on my list.

[nuno12345]

I did, I tested every single fuse, no difference.

Hmm, probably you wont like it :P my supply is the computer USB