What is the simple way to interface the I/O lines of LPC 2138 ARM?

Hai

Which is the simple way to interface the I/O lines of LPC 2138 ARM which works on 3.3Volts to circuits which works on 5Volts.

also will the control and data lines of LCD (HD4470) respond to 3.3 volt levels?

picstudent

Re: 3.3V to 5v levels?

One easy way of connecting 3.3V outputs to 5V inputs is to add a 1-10kΩ pullups ..
This technique is described in some details here:
**broken link removed**

The same "trick" you can try on the HD4470 ..

Regards,
IanP

3.3V to 5v levels?

picstudent there are ic that can inteface 3.3V with 5V.

but i think if the i/o lines not too many you can use transistor BJT.

Re: 3.3V to 5v levels?

Keep it simple use a Bus Switch

Re: 3.3V to 5v levels?

Hai

Got the details and thanks for the same.but some clarifications.

can you briefly explain the schematics how the 10k 1k arrangement or the possibility of using any buffer ics which we can connect 3.3 at input and drive it with 5 volts so that o/p woill be 5 v level.

Power drain is not much a criteria in my application. the 3.3V device should be safe.

I am trying to interface Keil MCB2130 board to LCD displays 7 segment displays and other 5 volt systems which I was using so far. The Keil board is a costly thing for me. So trying to be more cautious.That is all.

What is the meaning of "5 volt tollerent "pin of ARM? Will it with-stand a pull up from 5 volt in output mode? or only on input mode?

Which are the special chips for this purpose?
picstudent

Re: 3.3V to 5v levels?

"5V tolerant" means exactly this: you can have pullups connected to 5V Vcc ..

74LVX4245 is the "special" chip for this purpose ..
**broken link removed**

However, if you need to "translate" just one control line you can use 2 BJTs + pullups .. see attachement ..

Regards,
IanP