Pull up register

[Kengo]

Hi everybody..

we are connected pull up register before voltage (2.3v)
we are connected pull up register(1.5K ohm) in between STM32f429 controller and DP83848 device. after that voltage is same (2.3v) , But supply voltage of pull up 3.3v.....MY QUESTION IS

Why signal voltages are not increases after the pull up applied?

Signal voltage 2.3v
Pull up supply voltage is 3.3v
Required signal; voltage is 3.3v
But,Getting signal voltage 2.3v

 

[(*steve*)]

I think you mean "pull up resistor"

Depending on the nature of the output, the pull up resistor may so nothing. It could be a PWM or pull output with the voltage varying between 0V and 3.3V and a duty cycle such that the average value is 2.3V.