pic16f877a not working

[gzaloprgm]

connect pic16f877a to power in the circuit

Hi! I am having some weird problems with my pic16f877a.

First of all, the programmer (JDM2) does not recognise it, but I clearly remember that a few months ago it was recognised perfectly.

If I add +5V and GND from an external supply (connected to the ICSP connector) it works fine.

After that, I program it with WINPIC800 (data gets verified OK), but then the
problem comes:

When I put it in a simple led blinker circuit, it does nothing, every I/O pin has 0.2V but they dont disipate power (I think they are in Z state)

Already tried by changing the 20MHZ crystal to a 4 (XT), and 12, with no result.

I have a Reset pin pulled up to +V, tried with 1K, 10K, 0O, nothing helps.

My fuses are:
WRTff
LVPff
CPDff
CPff
DEBUGff
WDTENff
PWRTENff
BORENff

I am doing the circuit in a protoboard, with 1000µF capacitors and 1.2 pF to filter the power supply.

Can anyone help me?

Am I missing some thing?

Thanks!
Gzaloprgm

 

[similor]

to make sure pic16f877a not working

hi
First,u should ensure that the circuit must be low power when u programe online.Or u should connect the board power(+5v GND).
2.when u changed the xtal,u should change the xtal setting,like HS,XT,....etc.It's can be defined in the config words.

Try it.

 

[gzaloprgm]

pic16f877a + gnd

hi
First,u should ensure that the circuit must be low power when u programe online.Or u should connect the board power(+5v GND).
2.when u changed the xtal,u should change the xtal setting,like HS,XT,....etc.It's can be defined in the config words.

Try it.

1: When I put the Pic into the socket of the JDM programmer (no extra circuit), it does not get recognized. I need to add an external supply.

2: I already tried that (used HS in 12MHz and 20MHz, XT in 4MHz)

Added a .1uF disc capacitor between +V & GND (as near as possible to the IC), nothing changed.

Added two 22pF tantalum capacitors from the crystal to GND, nothing changed.

At test time, MCLR is 4.99V, OSC1 is 0.01V and OSC2 is 0.48V.

My code is this one:

 LIST P=16F877A
 INCLUDE <P16F877A.INC>

 ORG 0x00

 BCF STATUS,RP1 

 BSF STATUS,RP0
 CLRF TRISB

 BCF STATUS,RP0
 movlw 0xAA
 movwf PORTB
 goto $
 END

Thanks for your help,
Gzaloprgm

 

[blueroomelectronics]

pic16f877 not working

JDM programmers are notoriously unreliable on modern computers.

 

[gzaloprgm]

pic16f877 connecting xtal

OK, What other way do I have then to program the Pic16f877a to make a ICD2 clone?

 

[blueroomelectronics]

how to connect power to pic16f877a

That's one way, but you still need to program the programmers PIC. Of course a kit would come with a preprogrammed PIC and a nice PCB. They're not expensive.

 

[afghan77]

please when you write a c code, indicate the compiler you used

Added after 1 minutes:

if it is PIC you use all the time, then EASYPIC5 is the perfect solution to the problem, because it is dedicated to PIC.

 

[pranam77]

pic16f877a not work with 20mhz crystal

Get a Cute pic programmer for most of the popular pic devices from "www.united77.com" which works on the USB port. A complimentary programming board will be provided which after fitting it over the main board, with just 4 nuts and bolts, will look like the 2nd picture A complete PIC programmer which also supports ICSP. More details of supproted devices may be downloaded from **broken link removed**.