Resistor Differencces: 4.2 vs 4.3


 
W

WBegg

TVWBB Pro
Hey All,

So I'm finally getting around to putting together a 4.3 board, and noticed that the values for the LED current limiting resistors and the button select resistors differ from the 4.2 board.

As I don't have these values available, would it be a mistake to use the 4.2 values? I don't guess it would hurt for the LEDs, but I'm concerned about the button select resistors.

Thanks in advance.
 
If I remember correctly a voltage rail was removed from the LED board to simplify layout which changed the rail that the LEDs and buttons were connected to. For the LEDs the resistors are probably close enough, although will be brighter or dimmer than prior. The push buttons are sampled using an analog voltage that is dependent on the resistor values being correct. The buttons won't work correctly with the old values.
 
OK. Figured it out. The new board references 5v in the button circuit, and the old board references 3.3 volt.
 
Last edited:
You must log in or register to reply here.

 

Back
Top