Led blinking not working in breadboard

Thread Starter

PY01A0080

Joined Mar 7, 2013
42
here is the new image of the breadboard.
the Two capacitors of 33pF are connected to the crystal and the ground without resistor.
 

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LDC3

Joined Apr 27, 2013
924
There doesn't seem to be any incorrect wiring and the program look fine. Maybe the chip didn't take the programming. Did you program the chip more than once?
 

Thread Starter

PY01A0080

Joined Mar 7, 2013
42
yes i tried more than one to program the chip.
i can't explain why it's working with development board and with the breadboard.

I'm confused and stuck at this point.
 

DerStrom8

Joined Feb 20, 2011
2,390
The black wire is doing nothing. The buses on the breadboard are already connected internally.

Make sure your LED leads aren't shorting. They almost look like they are in the picture. also, make sure they're not backwards.

Also, do what kubeek suggested--write a simple program to just turn on the LEDs (not flash them) and see if it works. Also try putting the LEDs on other outputs. My guess is that either you're not programming the chip correctly, or you already fried it somehow.

What are you using for a power source?
 

absf

Joined Dec 29, 2010
1,968
Did you try adding the reset circuit to the RST pin of the 8051?



I think it is also a good idea to add a 0.1uF and a 10uF capacitors between the Vcc and Gnd of your breadboard.

Allen
 

Thread Starter

PY01A0080

Joined Mar 7, 2013
42
Thank you Absf,

you are right, i added the 10uF and the resistor 8.2K to the pin 9 and now it's working,
my leds are flashing.

Thank you all for your support, it was useful for me.
 

DerStrom8

Joined Feb 20, 2011
2,390
Thank you Absf,

you are right, i added the 10uF and the resistor 8.2K to the pin 9 and now it's working,
my leds are flashing.

Thank you all for your support, it was useful for me.
Didn't I tell you to connect your reset to ground through a resistor?

The cap probably isn't necessary, but it is definitely better to have it.
 

Thread Starter

PY01A0080

Joined Mar 7, 2013
42
yes you did, i remove the cap and it's working well.
i'm sure i made a mistake somewhere during connection the reset and the resistor before.
And the black wire is not necessary because the line is interconnected in the breadboard.
Thank you DerStrom8 to remind me.
i keep the diagram of Absf.
 
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