Espressif Systems ESP8266EX Hardware User's Manual page 29

Espressif Systems
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Interface
HSPI
SDIO/SPI
PWM
IR Remote Control
ADC
I2C
UART
Relay Control Terminal
Espressif Systems
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SPI Flash 2, display screen, and MCU can be connected using HSPI
interface.
Flash, host MCU, display screen, etc. can be connected using SDIO/SPI
interface.
Currently the PWM interface has four channels, but users can extend the
channels according to their own needs. PWM interface can be used to
control LED lights, buzzers, relays, electronic machines, and so on.
The functionality of Infrared remote control interface can be
implemented via software programming. NEC coding, modulation, and
demodulation are used by this interface. The frequency of modulated
carrier signal is 38KHz.
ESP8266EX is embedded with a 10-bit precision SARADC.
ADC_IN interface is used to test the power supply voltage of VDD3P3
(Pin 3 and Pin 4), as well as the input voltage of TOUT (Pin 6). It can be
used in sensors.
Sensors and display screens with 2.54mm and 1.27mm needles can be
connected using I2C interface.
UART0: U0TXD, U0RXD, MTDO(U0RTS), MTCK(U0CTS)
UART1: GPIO2(U1TXD)
Devices with UART interfaces can be connected.
Downloading: U0TXD+U0RXD or GPIO2+U0RXD
Communicating: UART0: U0TXD, U0RXD, MTDO(U0RTS), MTCK(U0CTS)
Debugging: UART1_TXD (GPIO2) can be used to print debugging
information.
By default, UART0 will output some printed information when the device
is powered on and is booting up. If this issue exerts influence on some
specific applications, users can exchange the inner pins of UART when
initializing, that is to say, exchange U0TXD, U0RXD with U0RTS, U0CTS.
R1/3/5/7 should not be mounted with other components, while
R2/4/6/8 can be mounted with other components.
J14 and J67 should be short-circuiting connected.
Relay control terminal is used to control the switch on-and-off of smart
plugs. There is an indicator light.
Table 4 Functions of Interfaces on ESP-LAUNCHER
29 48
ESP8266EX
Functions
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Hardware User Guide
Jun 1, 2015