What is the difference between XPD_DCDC and chip_en pin?
When CHIP_EN pin is HIGH chip works properly when LOW chip consumed an only small amount of current. Pin8: XPD_DCDC is an input/output pin which is used to wake up the chip from deep sleep mode. Commonly it is connected with GPIO16.
What is the difference between pin 21 and pin 22 on SDIO_CLK?
Pin21: SDIO_CLK is an input/output pin labeled as GPIO6 and used to connect with the clock pin of SD card. Pin22: SDIO_DATA_0 is an input/output pin labeled as GPIO7 and used to connect with data pin 0 of SD card.
How to do module reset with ch_PD line?
It seems that module Reset can be done with CH_PD line (pulling it low) leaving Reset alone with pull-up. And leaving Reset alone seems to be better for sleep/wake up mode (when GPIO16 connected to Reset) and avoid some problems in this case. I decided to give a try.
What is the function of pin 27 on the SPI chip?
Also used as SPI Chip Select pin 1 (SPI_CS1). Pin27: XTAL_OUT is classified as an input/output pin and connected to the output of the crystal oscillator. Pin28: XTAL_IN is classified as an input/output pin and connected to the input of the crystal oscillator. Pin29: VDDD is a power pin provide analog power ranges from 2.5V to 3.6V.
What does the Ch_pd pin do?
These are the pins for comunication. The middle pins on the bottom are CH_PD(chip power-down) and RST(reset). The main thing to remember is, that this device works with 3.3V;even the RX and TX pins.
What is esp8266mod?
The ESP8266 WiFi Module is a self contained SOC with integrated TCP/IP protocol stack that can give any microcontroller access to your WiFi network. The ESP8266 is capable of either hosting an application or offloading all Wi-Fi networking functions from another application processor.
What is ESP on Wi-Fi?
ESP-WIFI-MESH is a wireless communication network with nodes organized in a mesh topology using the simultaneous AP-STA feature on Espressif SoCs. It provides a self-forming and self-healing network, with ease of deployment.
What is MCU in NodeMCU?
The name "NodeMCU" combines "node" and "MCU" (micro-controller unit). The term "NodeMCU" strictly speaking refers to the firmware rather than the associated development kits. Both the firmware and prototyping board designs are open source. The firmware uses the Lua scripting language.
History
When I created the original WifInfo board, I’ve done it on a breadboard before creating the PCB design. I wanted to use an “auto-reset” feature as on Arduino to avoid playing with button on each upload.
WifInfo board
But in my design case, I don’t want to have USB Serial converter (for price, size and soldering) on my board and I’m using classic FTDI modules with only DTR line and no RTS. So I started with schematic from excellent Adafruit Huzzah that I improved for Auto Reset.
Google around on reset function
So after I googled around to see what others are doing with Reset ( here, here telling to connect DTR to CH_PD and here ), I found interesting point. It seems that module Reset can be done with CH_PD line (pulling it low) leaving Reset alone with pull-up.
Final Design
Anyway, here is the final schematic for auto-reset with FTDI module, it works in all case with my different modules. You can use either 3V3 or 5V FTDI modules, but with 3V3 you may need to power ESP with another source since 3V3 FTDI modules are not all able to source sufficient current, don’t forget this point!
What are the pins on an ESP8266?
The ESP8266-01 is the smallest ESP8266 module and only has 8 pins. Of these VCC, GND, RST (reset) and CH_PD (chip select) are not I/O pins but are needed the operation of the module. This leaves GPIO0, GPIO2, TX and RX available as possible I/O pins, but even these have pre-assigned functions. The GPIO0 and GPIO2 determine what mode the module starts up in and the TX/RX pins are used to program the module and for Serial I/O, commonly used for debugging. GPIO0 and GPIO2 need to have pull-up resistors connected to ensure the module starts up correctly.
What is ESP8266-01?
ESP8266-01 is a very low cost WiFi enabled chip. But it has very limited I/O. At first glance, once you configure it for programming all the pins are used.
Why is GPIO1 used as a data line?
A few things to note: GPIO1 (TX) is used as the Data line, because you will always get some debug output on GPIO1 on power up. There is no way to suppress this output, but the Clock line (RX) will be held high so none of this data will be clocked to the slaves.
What are pull up resistors?
The pull-up resistors, R1 and R3, provide the necessary High for these two pins, but you have to ensure that any extra circuitry attached to GPIO0 and GPIO2 cannot not pull pins low. The optically isolated relay is connected between +3.3V and GPIO0. This keeps GPIO0 high on start up but allows GPIO0 to be made an output, after startup, and ground the relay input to operate the relay. It does not matter if the momentary push button is operated while the module is initializing, as that just connects GPIO0 to GPIO2 and connect both of these to their pullup resistors.
What is another pin not to forget?
Another PIN not to forget is EN (also named CH_PD on other devices). This need to be pulled high in order the device to work.
What port is CP2102 connected to?
Connect CP2102 to computer and identity COM port.
What is XPD_DCDC pin?
Pin8: XPD_DCDC is an input/output pin which is used to wake up the chip from deep sleep mode. Commonly it is connected with GPIO16.
What is the MTDI pin?
Pin10: MTDI is an input/output pin labeled as GPIO12 and it is used in SPI as Master-In-Slave-Out pin (SPI_MISO).
What is the function of pin 6?
Pin6: TOUT is an input pin functions as ADC pin to test the supply voltages of Pin3 and Pin4 and the input voltages of TOUT pin6. These two functions cannot perform simultaneously.
What is GPIO0 in SPI?
Pin15: GPIO0 is an input/output used as Chip Select pin2 in SPI (SPI_CS2).
How many pins does NodeMCU have?
NodeMCU development board has a total 30 pins in which 14 pins are active, uses ESP-12 module, onboard reset and flash button, 3.3 voltage regulator, Micro USB, USB to UART Bridge and some other components.
How many pins are in ESP8266?
This board is not breadboard friendly often separate programming module is used for programming. It has a total 8 pins in which 6 pins are active.
How many pins are in a Wemos D1?
Wemos D1 Mini development board has a total 16 pins in which 12 pins are active, uses ESP-12 module, onboard reset button, 3.3 voltage regulator, Micro USB, USB to UART bridge and some other components.
Setting up the Arduino IDE for the WeMos D1 mini
This tutorial assumes that you have set up the Arduino IDE to able to compile the Wemos D1 mini.
Difference between the Arduino and WeMos D1 mini pins
One of the problems you will encounter when programming the WeMos D1 is that pin 1 on the WeMos isnt pin 1 in the Arduino IDE. The pin numbers in the WeMos D1 Pro (the ESP8266) are differently numbered than the Arduino.
Example Blink Sketch for WeMos D1 mini
To demonstrate using these constants I have rewritten the Arduino blink sketch using the WeMos D1 mini. The code is as follows:
