Crystal Oscillator

[tyyang]

Hi, i have some problems with the crystal oscillator. After i programmed my PIC16F877A, i found that there are problem with my output. At the 1st test, i trisB and set output B to be 0xff to light up all my LEDs at portB. Then i switch on Sk40C, the LEDs did not work until i touch the crystal oscillator then only portB can be functioning. At first i thought that i din't connect well the crystal oscillator(original) and so i retest it but still the same thing happend that i need to touch the oscillator to get the portB function.

And so, i also tried load with different programme. i tris, set all output to 0xFF and i also set LEDs at port B to blink repeatedly from 0xAA to 0x55. What i got from the result was i still need to touch on the crystal oscillator to get the LEDs blink. And when touch with an insulator material, nothing happen to the LEDs.

Thus i went to buy a new crystal oscillator and a new resonator. After testing with both new crystal oscillator and a new resonator, i still need to touch them in order to get the port to work.

Is there any thing or procedure that i have miss out? Please let me know, thanks.

[ober]

Maybe you can try solder the crystal to the connector on SK40C, sometime the bad connection will cause this error, but it seldom happen.