Need calrification about the voltage tolerence of LPC1788 GPIO

[mano_hw]

Dear Friends

We need some clarification about LPC1788 GPIO PIN input Voltage tolerance  ?

we already referred the data sheet that indicates the input voltage tolerance is 5v.

in Limiting values tables

5 V tolerant digital

V

DD(3V3)



2.4V

So please confirm I can give 5V input to the LPC1788 GPIO ?

Thanks and regards

Mano

[mano_hw]

Hi

What is the 2.4V means. Is that the controller input voltage or the reference voltage?

I have a ultrasonic sensor which will work on the input voltage of 5V. We have two pins(Trigger and Echo) . In these 2 pins the output voltage will be only 5V. Whether i can interface these pins with controller? Will it work?

[soledad]

On the LPC178x/7x, I/O pads are powered by VDD(3V3), this is the power supply voltage for I/O other than pins in the VBAT domain; while VDD(REG)(3V3) powers the on-chip voltage regulator which in turn provides power to the CPU and most of the peripherals.

The digital inputs are 5 V tolerant  (5 V tolerant if VDD(3V3) present; if VDD(3V3) not present, do not exceed 3.6 V) providing digital I/O functions with TTL levels and hysteresis.

For digital inputs you can handler 5v without issues, however for digital outputs the maximun output voltage is VDD(3V3).

Please consider that 3.3v is already a HIGH for TTL input pins, please check the below link you can find a conexion that you can use as reference:

Interfacing HC-SR04 Ultrasonic Distance Sensor with LPC2148 

Have a great day,
Sol
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[soledad]

Hi,

For general purpose digital input/output pins the input voltage tolerance is 5v only if VDD>=2.4v 

if VDD<2.4v then the input voltage tolerance is 3.6v.

I hope this clarifies.

Have a great day,
Sol
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[mano_hw]

Hi

What is the 2.4V means. Is that the controller input voltage or the reference voltage?

I have a ultrasonic sensor which will work on the input voltage of 5V. We have two pins(Trigger and Echo) . In these 2 pins the output voltage will be only 5V. Whether i can interface these pins with controller? Will it work?