准备

硬件

• NodeMCU-ESP8266开发板
• lcd1602显示屏（使用I2C总线）
• 杜邦线若干
• 可以联网的WiFi信号

软件环境

• Arduino IDE
• 心知天气API（免费版够用）

连线 NodeMCU——I2C

• GPIO4——SDA
• GPIO5——SCL
• VCC——3.3V
• GND——GND

GPIO overview

GPIO	Function	State	Restrictions
0	Boot mode select	3.3V	No Hi-Z
1	TX0	-	Not usable during Serial transmission
2	Boot mode select TX1	3.3V (boot only)	Don’t connect to ground at boot time Sends debug data at boot time
3	RX0	-	Not usable during Serial transmission
4	SDA (I²C)	-	-
5	SCL (I²C)	-	-
6 - 11	Flash connection	x	Not usable, and not broken out
12	MISO (SPI)	-	-
13	MOSI (SPI)	-	-
14	SCK (SPI)	-	-
15	SS (SPI)	0V	Pull-up resistor not usable
16	Wake up from sleep	-	No pull-up resistor, but pull-down instead Should be connected to RST to wake up