ESP8266 Community Forum

- Sun Aug 02, 2020 2:58 pm #88163 Hello.

I have a DM-101 serial WIFI v1.0 board that I have connected to my arduino UNO.
https://www.ebay.com/itm/ESP8266-Serial-Wifi-Transceiver-Module-for-Arduino-ESP-07-V1-0/311619662505?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Info:

This is WiFi serial transceiver module, based on ESP8266 SoC.The SOC has Integrated TCP/IP protocol stack.It is TTL serial communication interface and its parameters can be set by AT command. It is widely used in networking, smart home project when it is connected to the wifi router. It can be used for remote monitoring of home appliances, bedroom temperature and humidity, controlling home appliances and smart car by the mobile phone.

Features:
Arduino UNO R3 and the compatible board can directly connect to this module.
Interface logic voltage: 3.3V / 5V compatible(On-board level shift circuit)
Working voltage: 4.5V - 5.5V (On-board 3.3v LDO Regulator)
Working current: 240mA(MAX)
Serial port baud rate: 115200 (default), can be modified to other values by AT command
Serial communication format: 8N1
On-board reset button
On-board switch to select UART mode or firmware update mode
Antenna Type: Built-in ceramic antenna is available, and you can also use an external antenna.
Wireless Network Mode: station / softAP / SoftAP + station
Wireless criteria: 802.11 b / g / n
WIFI @ 2.4 GHz, support for WPA / WPA2 security mode
It is very easy to design projects by AT command
Applications: Home automation, sensor networks, industrial wireless control, smart car.

When pressing reset on the DM-101 i get the following information in the terminal:

15:43:07.662 -> ets Jan 8 2013,rst cause:2, boot mode:(3,6)
15:43:07.662 ->
15:43:07.662 -> load 0x4010f000, len 1264, room 16
15:43:07.662 -> tail 0
15:43:07.662 -> chksum 0x42
15:43:07.662 -> csum 0x42
15:43:07.662 -> ~ld

This at 74880baud. When I send an AT command i do not receive anything. (Sending both NL & CR)
Since I receive test when pressing reset on the DM-101, i assume that the wiring on the arduino is correct.

I have reset pin an ground together on the arduino.
VCC to 5V
GND to GND
RX to RX
TX to TX

Any ideas?

Thanks.

Koenraad

- Mon Aug 03, 2020 1:18 am #88169 after this boot message @74880 the fw switches to the operational baudrate, either 9600 or 115200 (depends on version). Easy check: send AT (+ cr/lf) and see if you get OK response.
Earlier versions had problems to permanently change baudrate via command and got bricked, so be carefull.
there is a special forum section for AT-fw

- Wed Aug 05, 2020 10:36 am #88198 Hello. Thank you for your reply.

I have tried it again. I connect the arduino and open the terminal.
When pressing reset I get an initial message from the ESP8266.

Then I change the baudrate in the terminal and enter AT + send. I tried on all baud rates but i never get a response.

I have attached a screenshot.

i am unfamiliar with how the controller operates, but it looks like it boots and gets stuck in a loop or something?

You do not have the required permissions to view the files attached to this post.

- Thu Aug 06, 2020 2:35 am #88210 Hi,
I don't remember if there were problems with the order of CR and LF or else...
Either try different terminal SW (putty, terraterm, etc) or maybe a different AT firmware.
look here for a start: viewtopic.php?p=88202#p88202