Weak pull-up in MCU

Helf

Hearding of the I/O ports of some MCU(eg.w925E240) with internal weak pull-up,so,how about the value of the weak pull-up resistor?

aquasnake

<P> usually we choose 10K for pull-up Res value when Vdd=2.8v(3.0v);</P><P>4.7K for IIC pull-up Res</P><P>10K for storage falsh card Data\Cmd pin pull-up</P>[br]<p align=right><font color=red>+5 RD币</font></p>

Helf

I mean the internal pull-up Res,and I also heard 5.1K for ⅡC pull-up Res,is it OK ? Or the pull-up Res for ⅡC has an allowable values in some scope .

aquasnake

<P>5.1K for 5v system IIC, tipical application by Philips</P><P>4.7K for 3v(2.8~3.3v) system IIC</P><P>its my choice</P>[br]<p align=right><font color=red>+3 RD币</font></p>

debowe

agree with aquasnake.

flyman135

great !

cwyoung

<P>The internal weak pull-up is non-linear.  if you pull-down the pin, the internal pull-up resister will be shut off automaticly.</P>[br]<p align=right><font color=red>+1 RD币</font></p>

swboy

<P>very good!TKS</P>