ESP8266 Community Forum

- Wed Sep 02, 2015 1:35 pm #27642 Hi

I ma using the esp8266 12 development board by tonixlabs
http://tronixlabs.com/wireless/esp8266/ ... australia/

the schematic can be found here

viewtopic.php?f=13&t=2694

However after spending considerable time, I am unable to establish any sort of serial communication with the module. there is not a single output on the serial terminal, not even garbage. absolutely nothing.

My setup is that I have connected
JP2.7 ->JP2.8 which is GPIO15 -> GND
JP2.6 -> JP1.8 which is GPIO2 -> VCC
JP1.3 -> JP1.8 which is CH_PD -> VCC
TTLTx -> JP5.3 which is for serial connection
TTLRx -> JP5.1 which is for serial connection
TTLGND -> JP5.2 which is GND -> GND.

Having done this, I supply the power from a power bank which is rated as output 5V/2A. I have cut the AA cell holder wire and soldered it with USB wire which connects to the power bank.

For serial connection I use Putty or Arduino IDE Serial monitor.

However after all the steps and wasting hours, nothing is shown on the serial terminal. NO Ready, or
<www.ai-thinker.com> message etc. so nothing is shown. I even crossed the Rx and Tx connection but still nothing is shown. I have checked that all connections are indeed proper. When JP4 is removed, the module powers up and I can see on my smartphone the name of the wifi access point as AI-Thinker and some numbers but no serial connection is established.

Can you please suggest what might be I missing?

I have changed different baud rates but no garbage even.a

- Wed Sep 02, 2015 5:04 pm #27656 On the schematic is the following note: Marking of RX and TX on JP5 is wrong on the actual bord

... so double-check your serial connection.

Also, what serial to USB interface are you using? Have you confirmed that it works? Did you also connect the DTR and RTS lines? If so, try disconnecting them.

I don't have that board... but on my handmade boards I've had no problem with serial connections. The ESP8266 always puts out something when it boots.

- Wed Sep 02, 2015 5:08 pm #27658 Yes, Kenn is right !
If the DTR pin is low during communication, it bring GPIO0 to LOW, so it stays in Upload mode.

- Thu Sep 03, 2015 3:03 am #27687 I am using Prolific Serial to USB cable. this cable has 4 output wires. Tx, Rx, VCC and GND.

Yes I also noted that the marking of Tx and Rx is opposite. So I have tried interchanging the Tx and Rx connection. but nothing is helpful.

The DTS and RST pins are not connected. Made connections are only the ones I mentioned in the OP.

May be it can be a module fault?

I have tested the cable b connecting Tx and Rx of the cable and I see the echo of all the inputs in the serial terminal.