[General] The matrix does not work

[kalinga]

The attached circuit diagram and hex file I received from my friend. It works well with the Proteus. But when practically created, it does not work. Anyone can guess what is the reason for it. I have only the circuit and the hex file.

 

[KlausST]

Hi,

"it does not work" is no usuful discription for us to find an error.
Give an error description: What happens exactly?

Possible issues:
* what power supply current do you consider? Is your power supply able to generate this? Is the wiring able to carry the current with respect to the voltage drop?
* Usually you need current limiting resistors for the LEDs.
* maybe you overdrive the GND_pin_current limit of the microcontroller.
* use a bulk capacitor for the power supply
* use a ceramics capacitor as close as possible to the power supply pins of the microcontroller.
* maybe you need to drive the RESET pin with correct level.

Klaus

 

[kalinga]

I used 8x8 ready made LED Matrix and The circuit was assembled on the Breadboard. My power supply current is 2A. When the circuit is connected to the power supply, all LEDs are lit simultaneously. Sometimes few LEDs or all LEDs are half dimmed.

 

[KlausST]

Hi,

If you want to use any IC you need to read its datasheet. (Even we professionals need to do this - sadly)

it says:

Under steady state (non-transient) conditions, I_OL must be externally limited as follows:
Maximum I_OL per port pin: 10 mA
Maximum I_OL per 8-bit port:
* Port 0: 26 mA
* Ports 1, 2, 3: 15 mA
Maximum total I_OL for all output pins: 71 mA
If I_OL exceeds the test condition, V_OL may exceed the related specification.
Pins are not guaranteed to sink current greater than the listed test conditions.

I assume you overdrive these specified limits by far.

Klaus