Unable to pull GPIO0 down

[jdkanani]

I am not sure what causing this issue. But, flashing with native SDK firmware works well. First time I used arduino compiled binary (using esptool-ck to flash via raspberrypi) causes this issue:

esptool-ck/esptool -vv -cd none -cb 115200 -cp /dev/ttyAMA0 -ca 0x00000 -cf main.ino.generic.bin

I am using board none - not sure if it has anything to do with that. More info about this problem: https://github.com/esp8266/Arduino/issues/1474

@igrr any idea?

[igrr]

I think esptool doesn't (shouldn't) care what kind of binary (compiled with Arduino of IoT SDK) it flashes. If you are using -cd none, it will not manipulate DTR and RTS pins. If you are connecting DTR/RTS pins to GPIO0, and want GPIO0 to be pulled low automatically, please use -cd ck or -cd nodemcu. It would be cool if you could list the steps to reproduce the issue for me, so that I may be able to help you.

[jdkanani]

Here is the code I used to export binary from Esp8266 Arduino:

//
// main.ino
//
void setup() {
  pinMode(12, OUTPUT); 
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(12, LOW); 
  delay(1000); 
  digitalWrite(12, HIGH);
  delay(2000);
}

Export compiled binary option compiles and generates main.ino.generic.bin. I copied that bin file to my raspberry pi which is connected to ESP12 with following connections:

ESP12	RaspberryPI
VCC, CH_PD	3.3v
GND, GPIO15	GND
TX	RX
RX	TX
GPIO0	GND (To flash new firmware)

GPIO12 is connected to LED to check blink.

To flash that bin file I used following command:

esptool-ck/esptool -vv -cd none -cb 115200 -cp /dev/ttyAMA0 -ca 0x00000 -cf main.ino.generic.bin

While floating GPIO0, Blink example works fine. But, grounding GPIO0 again (second time, to flash new firmware) causes a hang in RaspberryPi.

Native SDK compiled binary works fine using this wiring.