I want to make a PIC 16F877 comunicate with a serial PC port

[Pedro Duarte]

Hi !

I would like to make a PIC 16F877 comunicate with a serial PC port.

I read that some precision oscilator is required for this task : the
internal and RC oscilation PIC modes are not suitable.

So, could you recommend me any crystal / ressonator which is cheap an
do the trick ? I don't want very fast baud rates ...

Is it simple to interface the oscillator with the PIC ?

Thanks

 

[Ron]

For a realy cheap crystal, a 3.58Mhz color TV crystal with two 22pF cap.

You can interface (almost) directly the PIC with a PC. Most PC serial
interface accepts 0 to 5V signals, no need for negative supply or a MAX232.
The PIC output is connected through a 100 ohm resistor to the PC. The PIC
input through a 2K2 to 10K resistor and two clipping diodes right at the PIC
input, preferably two Schottky like 1N5817 or BAT85.

Ron

"Pedro Duarte" <paraasnews@yahoo.com> a écrit dans le message de
news:fj5nsvs9v0qbp9b8hfln22up01f660outd@4ax.com...

Hi !

I would like to make a PIC 16F877 comunicate with a serial PC port.

I read that some precision oscilator is required for this task : the
internal and RC oscilation PIC modes are not suitable.

So, could you recommend me any crystal / ressonator which is cheap an
do the trick ? I don't want very fast baud rates ...

Is it simple to interface the oscillator with the PIC ?

Thanks

 

[Pedro Duarte]

On Mon, 1 Dec 2003 17:43:51 -0500, "Ron" <none@none.net> wrote:

Thanks, Ron !

For a realy cheap crystal, a 3.58Mhz color TV crystal with two 22pF cap.

You can interface (almost) directly the PIC with a PC. Most PC serial
interface accepts 0 to 5V signals, no need for negative supply or a MAX232.
The PIC output is connected through a 100 ohm resistor to the PC. The PIC
input through a 2K2 to 10K resistor and two clipping diodes right at the PIC
input, preferably two Schottky like 1N5817 or BAT85.

Ron