Design Consideration_ESP8266 07 Microcontroller_Pin out
NOTE: Review pinout after final design
You can find a good overview on the ESP8266 NodeMCU V1.0 pinout and recommendations on which pins to use here
| Pin | Function | Connection | I/O (project) | Comment |
|---|---|---|---|---|
| VCC | Power | 5V in | micro USB | |
| GND | Ground | micro USB | ||
| D1 | SCL | I2C bus | (GPIO5) | |
| D2 | SDA | I2C bus | (GPIO4) | |
| D3 | SW | KY40 Push switch | ||
| D4 | DT | KY40 (PinB) | (GPIO2) | |
| D5 | DT | KY40 (PinA) | (GPI014) |
| Pin | Connection | Function | Comment |
|---|---|---|---|
| VDD | 5V | Power | |
| GND | GND | Ground | |
| SCL | D1 | I2C bus | |
| SDA | D2 | I2C bus | |
| ADDR | GND | ADS1015 address | sets address at hex 0x48; configurable |
| ALRT | float | ADS1015 alert | not used |
| A0 | VDD | ADC Input1 | measure supply voltage |
| A1 | float | ADC Input2 | not used |
| A2 | MEAT | ADC Input3 | Meat probe thermistor jack |
| A3 | PIT | ADC Input4 Pit probe thermistor jack |
The table below lists the ESP8266 pin-out for the cloudSmoker project:
| Pin | Function | Connection | I/O (project) | Comment |
|---|---|---|---|---|
| VCC | Power | 3.3V power rail | Analog Power 2.5V ~ 3.6V | |
| GND | Ground | |||
| Rest | Reset | Pull Low to reset chip | Input | |
| CH_PD (EN) | Chip Enable | VCC / 4.7k pull-up | Pulled-high to enable ESP8266; connect to ground to disable ESP8266 | |
| GPIO0 | 1) Flash mode entry (low on startup), 2) I2C SDA | 1)GND through momentary switch 2) SDA (330 ohm resistor in series to SDA to limit current <12mA) if slave becomes stuck and holds bus down |
bidirectional | Pull low at startup to enter flash mode, otherwise I2C SDA pin |
| ADC (Tout) | Analog-Digital Converter | MUX (4066B Quad Switch) | Input | 0-1V 10-bit ADC; A0 (alias) in Arduino language |
| TXD (GPI01) | Transmit | FTDI RX pin | Output | Output only |
| GPIO2 | 1) Pull high during startup 2) I2C SCL | VCC/4.7k pull-up | bidirectional | |
| RXD (GPI03) | Receive | FTDI TX pin with 330 ohm protection resistor in series | Input | Input Only ESP8266 reboots following programming and 330ohm Protection resistor prevents RX shorting the programmer's output drive. |
| GPI04 | CLK on rotary encoder | CLK/4.7k pull-up | Input | bidirectional pin |
| GPIO5 | DT on rotary encoder | DT/4.7k pull-up | Input | |
| GPIO6-11 | Unavailable; dedicated to Flash Memory | |||
| GPIO12 | CTL-B 4066B quad switch | CTL-B/3.3k pull-down | Switch-B control | Turn Switch-B on/off for multiplexing |
| GPIO13 | Rotary Encoder switch | SW | Input | Push switch on rotary encoder |
| GPIO14 | CTL-A 4066B quad switch | CTL-A/3.3k pull-down | Switch-A control | Turn Switch A on/off for multiplexing |
| GPIO15 | Start-up | GND/10k pull-down | Must be driven low for normal start-up; High startup boot from SD card | |
| GPIO16 | Deep Sleep low power enable | REST/Schottky diode (cathode towards GPIO16) | Output | GPIO16 is the only pin belonging to RTC (real time clock) module. During deep sleep, GPIO16 pin is high. When RTC triggers wake-up, it drives GPIO16 pin low, which also drives REST pin low, tirggering a reset. Placing a diode between REST to GPIO16 blocks the High signal, allowing the device to wake-up |
