Re: ESP8266 blue LED does not light up, no response
Posted: Tue Jan 10, 2017 7:43 pm
jclmdt wrote:May I know what is bootloader mode? Why do I need to connect the GPIO to GND? I thought it is connected to gnd only when you want to flash firmware in?
The program you want to load is the firmware. It overwrites whatever program was there before. For example, if you had the code that responded to AT commands initially, this would get overwritten with your newly loaded program. Your new program is the only application that is present until you go through the same process on the next code change.
When a reset happens, and the GPIO lines are set to start with the boot loader, the blue led will give a brief flash. About 1/10 of a second and only once. After that it is waiting for the new code to be sent.