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Reduce power consumption with MCU running

PostPosted: Mon Feb 22, 2016 7:09 pm
by Roman1991
Hello,

I have used this simple code to turn on my esp201:
http://img.banggood.com/images/2014/xie ... 863201603C

Code: Select all#include <ESP8266WiFi.h>

void setup()
{
  WiFi.mode(WIFI_OFF);
  WiFi.forceSleepBegin();
  delay(10);
}
void loop()
{
}


with the WIFI module off. after disconnecting the red power led I am at 14.5mA.

The documantation states that the ESP has an ultra-low power MCU.

My question is, if the Wifi module is off, what caueses that high consumption and is there a way to reduce it?
Can it come from the firmware EEPROM?


Edit:
If i'm not mistaken the eeprom type is 25Q40.
Attached is the dc characteristics.
Which of the consumptions in the table is relevant normal operation? (What frequency does the eps use to read the eeprom)

Thank you,
Roman

Re: Reduce power consumption with MCU running

PostPosted: Tue Feb 23, 2016 5:21 am
by schufti
Hi,

as you can see from this table the 15mA are lowest consumption with the cpu running. Only if one suspends cpu, lowering power consumption is possible.

Re: Reduce power consumption with MCU running

PostPosted: Tue Feb 23, 2016 5:34 am
by Roman1991
Thank you for the response.

The 15mA consumption consumption is for the whole board (including eps8266,eeprom,leds,resistors etc)

I am designing a circuit with the esp8266 and investigating which components should I place to reduce the 15mA consumption.
From the attached table you can see that the eeproms' consumption is ~10mA that means that the eps8266 itself consumes ~5mA.

So the question is if my assumtion correct?

Can i lower the clock speed that the esp reads the EEPROM to reduce the cosumption even lower?

Re: Reduce power consumption with MCU running

PostPosted: Tue Feb 23, 2016 5:48 am
by schufti
no, as you can see from the table, the esp8266 chip draws 15mA.
The flash is (no spiff used) only read once during boot and the "sketch" transfered into program memory in esp8266 for execution. The henceforth dormant flash consumes only µA if not powered up by direct access from sketch (eeprom, spiff, etc)