Lpc2000

Thank you very much!
I was not shure about the address lines A23-A2, now I am OK.
About the second question - yes, I figure it out.



--- In lpc2000@yahoogroups.com, "Kerem Or" <k.or@s...> wrote:
> 1) You can use external memory interface pins as GPIO.
> 2) You can check max input current of a pin under "absolute 
maximum ratings" 
> in the datasheet. Use a series resistor to limit the input 
current. The 
> resistor should be low enough not to degrade switching 
characteristics 
> because of the I/O capacitances/inductances and high enough to 
limit the 
> input current when 5V or whatever the voltage is applied to the 
input. 
> Usually the max input current is between 5-10 mA. For instance, a 
2K series 
> resistor would limit the input current to 2.5mA when 5V is 
applied. Assuming 
> this is protect the input from a transient condition, you should 
be fine. 
> But if the switching speed is high then 2K resistor will 
drastically affect 
> rise and fall times and will add propagation delay.
> It is totaly up to your application. But the idea is it is not the 
voltage 
> that destroys the input but the current.
> 
> Kerem
> 
> 
> 
> 
> ----- Original Message ----- 
> From: "Zdravko" <bodhisatva@m...>
> To: <lpc2000@yahoogroups.com>
> Sent: Tuesday, December 21, 2004 11:41 AM
> Subject: [lpc2000] LPC2214 questions
> 
> 
> >
> >
> > Hello,
> > I am going to use LPC2214.
> > I have some questions which are not clear for me in the User 
Manual.
> >
> >
> > 1) Can I use the not used external memory bus address lines as 
GPIO
> > (A0 and A1 are directly mentioned in the UM but the others not)?
> > 3) What are the limiting values of the voltage on the pins when 
the
> > 3.3V for the external rail is not present(The 1.8V for the core 
will
> > be on all the time)?
> >
> > Thank you very much and Happy Holidays.
> >
> > Regards
> > Zdravko
> >
> >
> >
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >