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Topic: Led matrix (Read 1 time) previous topic - next topic

JoeN

Do you have the two capacitors despiking the power line as recommended in the datasheet?  What is the resistor value for your single current limiting resistor?  Maybe that is off.  Hit it with a multimeter if you have one to be sure.

Code: [Select]
                LED Forward Voltage
           1.5V   2.0V   2.5V   3.0V   3.5V
For 40mA   12.2k? 11.8k? 11.0k? 10.6k? 9.69k?
For 30mA   17.8k? 17.1k? 15.8k? 15.0k? 14.0k?
For 20mA   29.8k? 28.0k? 25.9k? 24.5k? 22.6k?
For 10mA   66.7k? 63.7k? 59.3k? 55.4k? 51.2k?

I have only come here seeking knowledge. Things they would not teach me of in college.

siluk

Well I didn't put the capacitors, because it said it's not mandatory. I will buy the capacitors and try again. I attached the code of the book. I tried to modify the text in there and sometimes it runs well, depending on the text that's written. I guess there's something with the code, trying to figure out what...

JoeN


Well I didn't put the capacitors, because it said it's not mandatory. I will buy the capacitors and try again. I attached the code of the book. I tried to modify the text in there and sometimes it runs well, depending on the text that's written. I guess there's something with the code, trying to figure out what...


I was more worried about the resistor values.  Because what you said sounded like it started up and then stopped.  So I wonder if there is an overcurrent protection circuit or something that was kicking in because of a too-low resistor value allowing too much current to flow.  What is your resistor value?
I have only come here seeking knowledge. Things they would not teach me of in college.

siluk

My resistor value in the iset is 10K

Riva

If it works with come characters and not others it is probably over current try changing this line intensity(15); to intensity(1); the leds will be very dim but if it does work with all characters then you need to increase IREF value and/or improve power supply.

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