Anybody used a 16f877a pic

[6666]

Have you ever got a 16f877a to work
did you have to use an external crystal ?
thanks

[Altra]

Hi 6666

I did many years ago. What kind of problem are you having? Those chips only used external crystals or oscillators. No internal oscillator.

[Qiaozhi]

Have you ever got a 16f877a to work
did you have to use an external crystal ?
thanks

Yes, I've used the PIC16F877A successfully.
There are several oscillator options available, and a set of configuration bits is used to select various options.
Search for: "REGISTER 14-1:CONFIGURATION WORD (ADDRESS 2007h)" in the datasheet.
Bits 0 and 1 are used to set the oscillator type:
00 = low-power crystal
01 = crystal/resonator
10 = high-speed crystal/resonator
11 = resistor/capacitor

The resistor/capacitor is the low-cost option for timing insensitive applications.

[waltr]

I also have used these PICs years ago.
As Altra said, no internal oscillator so must use external XTAL, resonator or oscillator.

There are newer PICs that are pin compatible with internal oscillates.

[Qiaozhi]

Those chips only used external crystals or oscillators. No internal oscillator.

As Altra said, no internal oscillator so must use external XTAL, resonator or oscillator.

Neither of the above statements is true.
I have used a PIC16F877A in a timing insensitive application using the RC mode (does not require a crystal). I used R=3K3 and C=22pF.
The allowed range is 3k <= R <=100k, and C > 20pF.

[6666]

Thanks guys for your help, late last night I was working on a example code that lead me to believe the PIC16F877A had an internal INTOSC block, but it doesn't, and i thought my pic was faulty, however it can be configured as RC or crystal/resonator only . The example article made no mention that external parts (xtal) were required and i got a bit confused reading the data sheet late at night. Always something to learn.

[waltr]

Neither of the above statements is true.
I have used a PIC16F877A in a timing insensitive application using the RC mode (does not require a crystal). I used R=3K3 and C=22pF.
The allowed range is 3k <= R <=100k, and C > 20pF.

Yes, you are correct. A XTAL is not needed just an RC to get an oscillator.
Fine for Non critical timing.