ESP8266 Community Forum

- Thu May 28, 2015 2:36 am #18702 I have this all running ,connecting to a modem and posting data to Sparkfun .

What I don't understand is when powered through my USB port of my computer and FTDI cable giving 3.3 V the blue LED shows no light until it posts .

When I use a power supply like a battery or a wall wart through an Adafruit breadboard power supply kit giving 3.3 V the blue LED is often slightly lit and flashes when posting as usual .

It still seems to be doing what its supposed to do but I can't fathom the difference . What would cause that?

Last edited by tytower on Thu May 28, 2015 4:33 pm, edited 1 time in total.

Get you modules here:

https://www.banggood.com/custlink/KvGGhGF4wG

- Thu May 28, 2015 4:08 am #18707 I watched it some more in the dark . After a reset when it starts it comes on for a couple of seconds and after the deepsleep() reset it lights dimly for about 2 minutes of the sleep time and then goes out for the last minute of the deepsleep() which is 3 minutes in total.

I thought it might be the capacitor I have on the XPD----||----RST line which was pretty big but I changed that to a very small value with no effect on the LED.

Yes, the Blue LED is connected to the UART TX ...

So it must be transmitting something during deepSleep() ?

Get you modules here:

https://www.banggood.com/custlink/KvGGhGF4wG

- Wed Jun 03, 2015 11:08 pm #19415 Thinking a bit more about this . The device puts out a serial communication after each reset I think and I wonder if its trying to send this serial data for a predetermined time because the TX and RX lines are not connected in my application.

EDIT I found that what i thought was a 3.3V FTDI cable was a 5V giving out 4.76 V .so thoght that perhaps this was related in some way but the esp showing the blue light was doing so on a 3.3V adafruit power supply so I doubt its the excess power.

Last edited by tytower on Tue Jun 16, 2015 12:28 am, edited 1 time in total.

Get you modules here:

https://www.banggood.com/custlink/KvGGhGF4wG

- Mon Jun 15, 2015 9:29 pm #20545 On my ESP07 blue LED is connected to GPIO1 (which is also UART TX line). So, if you don't plan on using serial comm, or use UART2 (Serial2) this LED can be driven low to turn it on.

Code: Select all#define DIGITAL_PIN   1
#define LED_ON   digitalWrite(DIGITAL_PIN, 0)
#define LED_OFF   digitalWrite(DIGITAL_PIN, 1)

pinMode(DIGITAL_PIN, OUTPUT);