ESP8266 Community Forum

- Sat May 28, 2016 3:07 pm #48169 Hi,
I am new to this platform, and I bought a esp12-f module from ebay. I got a bare non breadboard friendly board. I made a custom breakout for this.
I have a LM1117 based based 3.3 v regulator from where I am taking the power.
For USB-TTL I am using PL2303 (fake though) board.
After just powering up (vcc and gnd only), I found no led to be flashing/blinking. But when I touched couple of pins like tx, CH_pd etc the led just blinked.
Now I added the rest of the connection and then I connected the serial converter to usb. Opened the arduino serial monitor, checked all baud rates but nothing appeared. I was following the following instructable:
http://www.instructables.com/id/Getting ... /?ALLSTEPS
The connections are:
VCC ----> 3.3V Power supply (Vout of LM1117)
GND ----> Ground of power supply
CH_PD ----> HIGH (3.3V)
GPIO2 ----> HIGH (3.3V)
GPIO15 ----> LOW (GND)
GPIO0 ----> HIGH or Floating for AT Mode (3.3V) [ * if you want to flash completely different firmware then you must connect it to ground ]
For my case I connected GPIO0 to gnd.
For The TTL I connected TX of TTL converter to RXD of esp and RX to TXD.
With this connections nothing appearing on my screen.
I have few questions.
1. It is advised to used PL2303 as the USB to TTL.
2. Should I use any voltage divider to convert it to 3.3v.
3. Some people are saying tx should go to TXD and rx should go to RXD. Can anyone confirm on this?
4. Can anyone please tally if the pin names and connections are in sync

Please help me.
Thanks,
Debojit

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IMG_20160529_011022_.jpg

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- Sun May 29, 2016 5:27 am #48200 Hi, you've done some good work there.
I think the main problem is GPIO 2 - yes it needs to be high at boot but can't be connected directly to 3.3V. It's better to use 10K pullups on GPIO's 0 & 2. This also makes it easier to flash the ESP is you can just short GPIO 0 momentarily to ground whilst powering up.
I personally use a 10K to pull GPIO 15 low, this prevents any damage to the output should I ever enable this as an output and set it high, in which case it would be directly shorted to ground.
If the output of your TTL is 5V, yes a voltage divider is needed 1K – 2K (2.2K) works fine.
Tx -> Tx & Rx -> Rx is the standard connection, it’s only if you are using an Arduino as a serial to TTL device you need to swap them round (the Arduino pins are not conventionally labelled).

Edit: You will need external power - the serial to TTL will not provide enough power to run an ESP.

- Sun May 29, 2016 2:48 pm #48230 Hi,
I could successfully ran AT command on the device.
Connections are
VCC ----> 3.3V Power supply (Vout of LM1117)
GND ----> Ground of power supply
CH_PD ----> HIGH (3.3V)
GPIO2 ----> HIGH (3.3V)
GPIO15 ----> LOW (GND)
GPIO0 ----> HIGH or Floating for AT Mode (3.3V) [ * if you want to flash completely different firmware then you must connect it to ground ]
everything fine.
then I added some 10k pullup register at CH_PD, RST, and GPIO2, also with GPIO0.
Then the problem started, I dont know what happened but it is not receiving any AT command.
At beginning the bootup message is also little different:
its like some gibberish then

rlòn't use rtc mem data
rlŽ‚rlÌÿ
Ai-Thinker Technology Co.,Ltd.

ready
WIFI CONNECTED
WIFI GOT IP

I think something went wrong. The I tried to communicate with espflasher tool, but no success.
It seems its not taking any input.
for PL2303 the tx is giving 3.6v so did not use any voltage divider.

Also while i touched few pins i got following output:
ets Jan 8 2013,rst cause:4, boot mode:(3,7)

wdt reset
load 0x40100000, len 1396, room 16
tail 4
chksum 0x89
load 0x3ffe8000, len 776, room 4
tail 4
chksum 0xe8
load 0x3ffe8308, len 540, room 4
tail 8
chksum 0xc0
csum 0xc0

2nd boot version : 1.4(b1)
SPI Speed : 40MHz
SPI Mode : DIO
SPI Flash Size & Map: 8Mbit(512KB+512KB)
jump to run user1 @ 1000

Any idea??
Please help.