Hello All,

I am having a prototype board with LPC2368 MCU on it. I try to follow the sequence of:

PCONP = 0x00;
PCON = 0x0e;

to disable all the peripherals and power down the MCU. But for some reason the current consumption on the device is still 15mA. As per the datasheet it should be in uA. I am not sure where the current goes.

By default I have all the gpio pins pulled up using PINMODE0-9 as 0x00000000 and the brown out circuit is power down too.

Please can anyone suggest what can cause the current consumption even if the MCU is powered down.

Thanks
Sincerely,

-Ajay Sharma Start a New Thread

Hi:

How are you measuring the VDD current? (shunt resistor, DMM, etc)?
Can you completely isolate the VDD that powers the MCU?

Does your measurement equipment has enough resolution to measure uA?

Are you sure that there is no other circuit connected to that VDD, like a voltage reference, LED, drivers, pull-down resistors, ADC reference, etc?

Is the RTC enabled during power down (to wake up the MCU)? With External Crystal (32KHz)?

Regards,

Alex Start a New Thread

It probably hasn't powered down. Is the main oscillator still running ?

Check earlier postings about USBneedclock, and power-down state of IO
port pibs.

Cheers,
Bruce Start a New Thread

dear,
i am using lpc2468 and pd current is 2.5mA.you should make PINMODE0-9 as 0xAAAAAAAAA INSTEAD 0X00,and also make pinsel as 0x00,CURRENT WILL DEFINATELY REDUCE........ Start a New Thread

To all who responded, Thank you.

I decided to write a piece of code which only enabled the external oscillator, executed a while loop for 10 seconds, then set PCON bit 0. The MCU drew 7.6 mA less when PCON was set. I was running at 12 MHz and no peripherals changed from their default.

Mark Crow | Senior Embedded Software Engineer
m...@ptm.com | www.ptm.com | Lat/Lon: 28.1853 N 82.5907 W Start a New Thread