16X4 LCD with LPC2129

[narithota]

Hi
How to interface 16X4 LCD with LPC2129
LPC2129 well work with 3.3V & 1.8V, But LCD well work with 5v supply
How to interface 3.3V logical High signals (data bits) with LCD
Please provide me
1. How much source & sink current will provide the LPC GPIOs.
2. How to connect 5V peripherals with LPC2129.
3. What precautions I have to take while connecting LPC2129 with peripherals
Thank you

Regards
nari

 

[bobcat1]

Hi

The LPC2129 can tolerate 5V input signal and 2.9V out put signal "1" on I/O pin

to operate a 5V lcd you will need a boost - circuit see TPS61040/1 from TI but there are many LCD who can work with 3.3V - try to connect 3.3V insted of 5V and see whether it is operating

All the best

Bobi

 

[bobsanjose]

May be this one is already out of date but for what its worth. As Bobi said, The inputs of the LPC2129 can tolerate 5V. What you could do is to connect a pull-up to the port pin, connecting it with 5V. If you drive the pin low, the max 4mA of the port pin have to be strong enough to get to low-level.
If you want to have a high-level, you put the pin into input (high impedance) mode and the pullup will take over.
Your challenge is to make the pull-up strong enough to provide the current needed for your LCD but weak enough that you can overdrive to low level with the output driven low.

hth, Bob

More information related to the LPC2000 family
http://www.lpc2000.com