From Makers Electronics's description
ESP8266 D1 R1 WiFi Processor with Uno Footprint The ESP8266 D1 R1 WiFi board utilizes the ESP8266 WiFi enabled processor, and puts it onto an Arduino Uno board footprint. It provides a way to work with the ESP8266 in a familiar setup and does not require a breadboard in order to make interconnections since it has the typical on-board female headers. It will also work with some Uno shields that have compatible I/O pin-outs. KEY FEATURES OF ESP8266 D1 R1: Microcontroller: ESP-8266 32-bit Clock Speed: 80MHz and up to 160MHz USB Converter: iFT232-S16 Operating Voltage: 3.3V Flash Memory: 4MB Digital I/O: 11 Analog Inputs: 1 Communications: I2C, Serial, SPI WiFi: Built-in Besides adding WiFi capability, the main claim to fame for the ESP8266 processor over the AVR processor of the standard Arduino is that it has a larger 4MB of Flash memory and runs at clock speeds of 80MHz and can sometimes optionally be overclocked to 160MHz and has a very fast processing speed. The Digital I/O except for D0 all support PWM and interrupts. In addition they can be configured to have pull-up or pull-down resistors On the down-side, it has only 1 analog input which is probably the most significant limitation. That can always be overcome by using an external Analog Mux module like our 16-channel 74HC4067, ADS1115 4-Channel 16-bit ADC or the MCP3008-I/P 8 channel A/D converter IC below if more analog I/O is desired. Per spec, the digital I/O is limited to 3.3V, but the ESP-8266 mfr has made statements that the digital pins are in fact 5V tolerant and there are many installations using the module directly connected to the logic lines of 5V peripherals. Note that when programming the board, you need to refer to the I/O using both the letter and number. With Arduino, output D3 would be referred to simply as ‘3’, but with the D1 board, you need to refer to the pin as ‘D3’. The board can be powered via the USB port or using an external 7-12V power supply via the DC Power Jack. The board runs at 3.3V, so keep that in mind when working with I/O. TECHNICAL SPECIFICATIONS Microcontroller ESP8266 32-bit Serial to USB Converter iFT232-S16 Operating Voltage 3.3V Input Voltage (recommended) 7-12V Digital I/O Pins 11 PWM I/O Pins (Shared with Digital I/O) 10 Analog Input Pins 1 (10-bit) DC Current per I/O Pin 12mA (Max) Hardware Serial Ports 1 Flash Memory 4 MBytes Instruction RAM 64 KBytes Data RAM 96 KBytes Clock Speed 80MHz Network IEEE 802.11 b/g/n WiFi Built-in LED Attached to digital pin 13 USB Connector Style Micro-B Female Board Dimensions (PCB) 69 x 53mm Pin Out Pin Function ESP-8266 Pin TX TXD TXD RX RXD RXD A0 Analog input, max 3.3V input A0 D0 IO GPIO16 D1 IO, SCL GPIO5 D2 IO, SDA GPIO4 D3 IO,Pull-up GPIO0 D4 IO,pull-up, BUILTIN_LED GPIO2 D5 IO, SCK GPIO14 D6 IO, MISO GPIO12 D7 IO, MOSI GPIO13 D8 IO,pull-down, SS GPIO15 G Gound GND 5V 5V – 3V3 3.3V 3.3V RST Reset RST *All IO have interrupt/pwm/I2C/one-wire supported(except D0) Note: All IO is work at 3.3V. Useful links iFT232-S16 Datasheet
Read moreShow less
Wireless Transmission Module With AntennaEGP 3001 shopPrice may be out of date (74 days)
Ralink USB Wifi ModuleEGP 3001 shopPrice may be out of date (74 days)
HC-05 Bluetooth ModuleEGP 3001 shopPrice may be out of date (74 days)
DC 5V RF Wireless Relay Control Switch 2CH 433MHZ with RemoteEGP 3001 shopchecked 11 days ago
SIM800L GPRS GSM Module Core Board Quad-band TTL Serial Port with the antennaEGP 2901 shopPrice may be out of date (74 days)
