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Topic: Can't start to work with indicators on MAX7219 and 74HC595 (Read 185 times) previous topic - next topic

alexnecro

Hello everybody!

I've bought on aliexpress two indicators:
4-in-1 1088as dot matrix on MAX7219
and
6-digits 7-segments on 2x 74hc595

Both do not work. Samples I found for hc595 shows something meaningless, but it's just a half of sadness: MAX7219 seems to be short-circuited, because some leds are always on, and some leds are always off (look at photo). Tested LCDemoMartix from LedControl.
I've modified startup code from LCDemoMatrix:
Quote
lc.shutdown(0,false);  lc.setIntensity(0,0);
  lc.shutdown(1,false);  lc.setIntensity(1,4);
  lc.shutdown(2,false);  lc.setIntensity(2,8);
  lc.shutdown(3,false);  lc.setIntensity(3,15);

And, look at photo: intensity changes, but only on two rows, and two columns on each matrix are off.
So, please help me to understand 74HC595 indicator (how to make it turn ON particular segment?), and please, guide me how to test MAX7219 indicator, because it seems not to be OK.

Thanks in advance!

and please, forgive me my terrible English (

alexnecro

I've measured voltages on dot matrix pin (after just apply power to MAX7219):
(16)++-+ --++(9)
( 1)+--+  -+--(8)

but according to that article
Pinout
pins must be connected as
(16)++-+ -++-(9)
( 1)--++  -+--(8)

and, after I call lc.clearDisplay(0), nothing changes

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