Superdat
Member
Hi
I've built a pcb as part of a bigger project which has 3 x Max7221 driving 3 banks of 7 segment LEDs x 8 digits
I.e. 8 digits per Max7221.
It is being driven with an Atmega328P on a development board using SPI.
I am using Oshonsoft AVR IDE and it's the latest version.
This is the 1st time I've tried cascading and after fixing the pcb problems and figuring out how to cascade, I've got it working.
However there is one problem, the LEDs on the 3rd bank flicker.
I noticed that the flicker is the difference between the character displayed in bank 1 and its equivalent digit in bank 3.
E.g. If bank 1 digit 1 is 7 and bank 3 digit 1 is 1, the top of the 7 (-) flickers in bank 3 digit 1
If I make bank 1 digit 1 blank, the flicker in bank 3 stops.
I thought it might be a timing problem and tried numerous variations but no success.
It's not the pcb hardware because I strung 3 ready made 8 digit 7 segment LEDs together and I get the same problem.
Any suggestions? Preferably based on some sort of logic
I've built a pcb as part of a bigger project which has 3 x Max7221 driving 3 banks of 7 segment LEDs x 8 digits
I.e. 8 digits per Max7221.
It is being driven with an Atmega328P on a development board using SPI.
I am using Oshonsoft AVR IDE and it's the latest version.
This is the 1st time I've tried cascading and after fixing the pcb problems and figuring out how to cascade, I've got it working.
However there is one problem, the LEDs on the 3rd bank flicker.
I noticed that the flicker is the difference between the character displayed in bank 1 and its equivalent digit in bank 3.
E.g. If bank 1 digit 1 is 7 and bank 3 digit 1 is 1, the top of the 7 (-) flickers in bank 3 digit 1
If I make bank 1 digit 1 blank, the flicker in bank 3 stops.
I thought it might be a timing problem and tried numerous variations but no success.
It's not the pcb hardware because I strung 3 ready made 8 digit 7 segment LEDs together and I get the same problem.
Any suggestions? Preferably based on some sort of logic
Last edited: