Using 'SOP / SSOP to DIP Adapter board', MAX7219 chipset and THIS scheme, I connected 14 LEDs in my project. I used a 20k resistor between 18 and 19 pin, and a 1k pull-down resistor. In the configurator I used the "Add LED Matrix, Max7219" function.
The LEDs can be switched on, but only one at a time. After switching on more than one at the same time, the LEDs turn off immediately. To restart it I need to use the "Hardware reconnect" function. What did I do wrong?