Espressif ESP8266 Series User guide

ESP8266
System Description
Version 1.5
Copyright © 2016

About This Guide
This document provides technical description of ESP8266 series products including
ESP8266EX, ESP-LAUNCHER and ESP-WROOM, including the following topics:
Release Notes
Chapter
Title
Subject
Chapter 1
ESP8266EX
Hardware description on ESP8266EX chipset including.technical
specifications, pin definitions, layout, and typical applications.
Chapter 2
ESP-LAUNCHER
Technical description on ESP-LAUNCHER with ESP8266EX built-in.
Chapter 3
ESP-WROOM
Technical description on ESP-WROOM-01 and ESP-WROOM-02
with ESP8266EX.
Date
Version
Release notes
2015.12
V1.3
First release.
2016.01
V1.4
Sections 1.5.2, 1.5.3 & 1.6 updated.
2016.06
V1.5
Section 3.1 updated.

Table of Contents
1. ESP8266EX 1 ................................................................................................................................................
1.1. Overview 1 ..................................................................................................................................................................
1.2. Specifications 2 ..........................................................................................................................................................
1.3. Pin Definitions 3 ........................................................................................................................................................
1.4. Schematics 5 ..............................................................................................................................................................
1.4.1. Power Supply 6 .................................................................................................................................................
1.4.2. Power-on Sequence and Power Reset 7 ...................................................................................................
1.4.3. Flash 7 ..................................................................................................................................................................
1.4.4. Crystal Oscillator 8 ...........................................................................................................................................
1.4.5. RF 8 .......................................................................................................................................................................
1.4.6. External Resistor 12K 9 ...................................................................................................................................
1.5. Layout Design 9 .........................................................................................................................................................
1.5.1. Standalone ESP8266EX Module 9 ..............................................................................................................
1.5.2. ESP8266EX as Slave Device 11 .....................................................................................................................
1.5.3. Typical Layout Problems And Solutions 13 ...............................................................................................
1.6. Application 15 .............................................................................................................................................................
1.6.1. Wi-Fi Smart Hardware Converted from UART Serial Ports 15 ............................................................
1.6.2. Sensor 15 ..............................................................................................................................................................
1.6.3. Smart Light 15 ....................................................................................................................................................
1.6.4. Smart Plug 15 ......................................................................................................................................................
2. ESP-LAUNCHER 16 .......................................................................................................................................
2.1. Overview 16 ................................................................................................................................................................
2.2. Schematics 19 .............................................................................................................................................................
2.2.1. Interfaces 19 .......................................................................................................................................................
2.2.2. 5V Power Supply 20 ........................................................................................................................................
2.2.3. Test Module 21 ..................................................................................................................................................
2.3. Test Board 21 .............................................................................................................................................................
3. ESP-WROOM 23 ...........................................................................................................................................
3.1. SMD Module ESP-WROOM-02 23 ........................................................................................................................
3.2. DIP Module ESP-WROOM-01 25 ...........................................................................................................................
3.3. Schematics 26............................................................................................................................................................

ESP8266EX
1. ESP8266EX
1.1. Overview
Espressif’s ESP8266EX delivers highly integrated Wi-Fi SoC solution to meet the continuous
demands for efficient power usage, compact design and reliable performance in the industry.
With the complete and self-contained Wi-Fi networking capabilities, It can perform as either a
standalone application or the slave to a host MCU. When ESP8266EX hosts the application, it
promptly boots up from the external flash. The integrated high-speed cache increases the
system performance and optimizes the system memory.
Also, ESP8266EX can be applied to any micro-controller design as a Wi-Fi adaptor through
SPI / SDIO or I2C / UART interfaces.
Besides the Wi-Fi functionalities, ESP8266EX also integrates an enhanced version of Tensilica’s
L106 Diamond series 32-bit processor and on-chip SRAM. It can be interfaced with external
sensors and other devices through the GPIOs, resulting in low development cost at early stage
and smallest footprints. Software Development Kit (SDK) provides sample codes for various
applications.
ESP8266EX integrates antenna switches, RF balun, power amplifier, low noise receive
amplifier, filters and power management modules. The compact design minimise the PCB size
and allows for minimal external circuitry.
ESP8266EX enables sophisticated features as follows:
•Fast switching between sleep and wake-up mode for energy-efficiency purpose;
•Adaptive radio biasing for low-power operation;
•Advanced signal processing;
•Spur cancellation;
•Radio co-existence mechanisms for common cellular, Bluetooth, DDR, LVDS, LCD
interference mitigation.
Figure 1-1 shows the functional blocks of ESP8266EX.
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ESP8266EX
Figure 1-1: ESP8266EX Block Diagram
1.2. Specifications
RF balun
Switch
RF
receive
RF
transmit
Analog
receive
Analog
transmit
PLL VCO 1/2 PLL
Digital baseband
MAC Interface
PMU Crystal Bias circuits SRAM PMU
SDIO
I2C
PWM
ADC
SPI
UART
GPIO
I2S
Flash
Registers
CPU
Sequencers
Accelerator
Table 1-1: ESP8266EX Specifications
Categories
Items
Parameters
Wi-Fi
Standard
CCC / FCC / CE / TELEC / SRRC
Protocols
802.11 b/g/n
Frequency Range
2.4 G ~ 2.5 G (2400 M ~ 2483.5 M)
Tx power
802.11 b: ＋20 dBm
802.11 g: ＋17 dBm
802.11 n: ＋14 dBm
Rx Sensitivity
802.11 b: －91 dbm (11 Mbps)
802.11 g: －75 dbm (54 Mbps)
802.11 n: －72 dbm (MCS7)
Antenna
PCB on-board, external, IPEX connector, ceramic chip
Hardware
Peripheral interface
UART / SDIO / SPI / I2C / I2S / IR Remote Control
GPIO / PWM
Operating voltage
3.0 V ~ 3.6 V
Operating current
Average: 80mA
Operating
temperature range
-40 ℃ ~ 125 ℃
Storage temperature
range
-40 ℃ ~ 125 ℃
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ESP8266EX
1.3. Pin Definitions
The pin assignments for 32-pin QFN package is illustrated in Figure 1-2.
Figure 1-2: ESP8266EX Pin Assignments
Table 1-2 lists the definitions and functions of each pin.
Package size
QFN32-pin (5 mm x 5 mm)
External interface
N/A
Software
Wi-Fi mode
station / softAP / SoftAP + station
Security
WPA / WPA2
Encryption
WEP / TKIP / AES
Firmware upgrade
UART Download / OTA (via network)
Software
development
SDK for customised development / cloud server development
Network Protocols
IPv4, TCP / UDP / HTTP / FTP
User configuration
AT Instruction Set, Cloud Server, Android/ iOS App
Categories
Items
Parameters
Table 1-2: ESP8266EX Pin Definitions
Pin
Name
Type
Functions
1
VDDA
P
Analog Power 3.0 V ~ 3.6 V
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ESP8266EX
2
LNA
I/O
RF Antenna Interface!
Chip Output Impedance = 50 Ω!
No matching required. It is suggested to retain the π-type
matching network to match the antenna.
3
VDD3P3
P
Amplifier power: 3.0 V ~ 3.6 V
4
VDD3P3
P
Amplifier power:3.0 V ~ 3.6 V
5
VDD_RTC
P
NC (1.1 V)
6
TOUT
I
ADC pin. It can be used to test the power-supply voltage of
VDD3P3 (Pin3 and Pin4) and the input power voltage of
TOUT (Pin 6). However, these two functions cannot be used
simultaneously.
7
CHIP_EN
I
Chip Enable
High: On, chip works properly
Low: Off, small current consumed
8
XPD_DCDC
I/O
Deep-sleep wakeup (need to be connected to EXT_RSTB;
GPIO16
9
MTMS
I/O
GPIO14; HSPI_CLK
10
MTDI
I/O
GPIO12; HSPI_MISO
11
VDDPST
P
Digital / IO power supply (1.8 V ~ 3.3 V)
12
MTCK
I/O
GPIO13; HSPI_MOSI; UART0_CTS
13
MTDO
I/O
GPIO15; HSPI_CS; UART0_RTS
14
GPIO2
I/O
UART Tx during flash programming; GPIO2
15
GPIO0
I/O
GPIO0; SPI_CS2
16
GPIO4
I/O
GPIO4
17
VDDPST
P
Digital / IO power supply (1.8 V ~ 3.3 V)
18
SDIO_DATA_2
I/O
Connect to SD_D2 (Series R: 200 Ω); SPIHD; HSPIHD;
GPIO9
19
SDIO_DATA_3
I/O
Connect to SD_D3 (Series R: 200 Ω); SPIWP; HSPIWP;
GPIO10
20
SDIO_CMD
I/O
Connect to SD_CMD (Series R: 200 Ω); SPI_CS0; GPIO11
21
SDIO_CLK
I/O
Connect to SD_CLK (Series R: 200 Ω); SPI_CLK; GPIO6
22
SDIO_DATA_0
I/O
Connect to SD_D0 (Series R: 200 Ω); SPI_MSIO; GPIO7
23
SDIO_DATA_1
I/O
Connect to SD_D1 (Series R: 200 Ω); SPI_MOSI; GPIO8
24
GPIO5
I/O
GPIO5
25
U0RXD
I/O
UART Rx during flash programming; GPIO3
26
U0TXD
I/O
UART Tx during flash programming; GPIO1; SPI_CS1
27
XTAL_OUT
I/O
Connect to crystal oscillator output, can be used to provide
BT clock input
28
XTAL_IN
I/O
Connect to crystal oscillator input
Pin
Name
Type
Functions
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ESP8266EX
1.4. Schematics
The highly integrated design of ESP8266EX tremendously reduce the number of components
required. Beside ESP8266EX, less than 10 resistors and capacitors, 1 crystal oscillator and 1 SPI
flash are needed to make a complete module with wireless communication capability. The
following is a detailed description on ESP8266EX schematics and layout design to ensure
optimum functionality.
The complete circuit diagram of ESP8266EX is illustrated in Figure 1-3.
Figure 1-3: ESP8266EX Schematics
ESP8266EX schematics design includes six aspects:
•Power supply
•Power-on sequence and reset
29
VDDD
P
Analog power 3.0 V ~ 6 V
30
VDDA
P
Analog power 3.0 V ~ 3.6 V
31
RES12K
I
Serial connection with a 12 kΩ resistor to the ground
32
EXT_RSTB
I
External reset signal (Low voltage level: Active)
Pin
Name
Type
Functions
Note:
GPIO2, GPIO0 and MTDO can be configured to a 3-bit strapping register that determines the
booting mode and the SDIO timing mode.
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ESP8266EX
•Flash
•Crystal oscillator
•RF
•External resistor
1.4.1. Power Supply
Digital Power Supply
ESP8266EX has 2 digital pins for power supply, pin11 and pin17. For digital power supply, there
is no need to add additional filter capacitors. The operating voltage range of digital power
supply pins is 1.8 V ~ 3.3 V.
Figure 1-4: ESP8266EX Digital Power Supply Pins
Analog Power Supply
ESP8266EX has five analog pins for power supply. including pin1, pin3, pin4 which provides
internal power supply for internal PA and LNA respectively, and pin28, pin29 which supply
power for internal PLL. The operating voltage for analog power supply pins is 1.8 V ~ 3.3 V.
Note that the power supply channel might be damaged due to the sudden increase of current
when ESP8266EX is transmitting analog signals. Therefore, an additional 0.1 μF capacitor with
a package size of 0603 or 0805 is needed in circuit design,which can match with capacitor
with 0.1 μF capacitor with 0402 package.
Figure 1-5: ESP8266EX AVDD
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ESP8266EX
1.4.2. Power-on Sequence and Power Reset
Power-on Sequence
ESP8266EX uses 3.3 V as the system power supply. It is not allowed that Pin7 CH_EN be
powered on prior to that the 3.3 V system power supply is powered on.
Reset
Pin32 serves as a RST pin which can be dangled when it is not used. The reset pin is held low
level when the chip is enabled. In order to avoid reset caused by external interference, the lead
is generally required to be short, and no external pull-up resistor is necessary.
Pin7 CH_EN can also be used as a reset pin. When the voltage for CH_EN pin is low, the chipset
will be powered off.
1.4.3. Flash
The demo flash used by ESP8266EX is SPI Flash with 2 MB ROM in SOIC_8 (SOP_8) package.
Pin21 SD_CLK is connected to the Flash CLK pin together with a 0402 resistor in serial
connection to reduce the drive current and eliminate external interruption. The initial
resistance of the resistor is 200 Ω.
Figure 1-6: ESP8266EX Flash
Note:
ESP8266EX’s EMC is in conformity with FCC and CE requirements, there is no need to add ferrite
beads in analog power-supply circuit.
⚠Notice:
If the power management IC is connected with the power-on enable pin CHIP_EN, it can control the
power on-and-off of ESP8266EX by output high and low voltage through its GPIOs. However,
pulsed current might be produced at the same time. In order to delay the transmission of pulsed
signal and avoid unstable current of CHIP_EN, a RC time-delay circuit (R=1 kΩ, C=100 nF) is needed.
⚠Notice:
Pin 7 CH_EN cannot be dangled.
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ESP8266EX
1.4.4. Crystal Oscillator
40 MHz, 26 MHz and 24 MHz crystal oscillators are supported. The accuracy of crystal
oscillators should be ± 10 PPM, and the operating temperature range should be between -20°C
and 85°C.
Select the corresponding crystal oscillator type in ESP Flash tool. In circuit design, capacitors C1
and C2 which are connected to the earth are added to the input and output terminals of the
crystal oscillator respectively. The values of the two capacitors can be flexible, ranging from 6
pF to 22 pF. However, the specific capacitive values of C1 and C2 depend on further testing
and adjustment on the overall performance of the whole circuit. Normally, the capacitive
values of C1 and C2 are within 10 pF if the crystal oscillator frequency is 26 MHz, while the
values of C1 and C2 are 10 pF < C1, C2 < 22 pF if the crystal oscillator frequency is 40 MHz.
Figure 1-7: ESP8266EX Crystal Oscillator
1.4.5. RF
The output impedance of RF pin (Pin2) is 50 Ω. Normally, when the antenna impedance
approaches 50 Ω, antenna matching is not necessary. However, some low-price antennas
commercially available in the market do not feature 50 Ω impedance. Besides, the impedance
in 2.4 G to 2.5 G frequency band is rather scattered. Therefore, π-type matching network-type
matching network is essential in circuit design to facilitate antenna matching.
⚠Notice:
Defects in the craftsmanship of the crystal oscillators (for example, high frequency deviation and
unstable working temperature) may lead to the malfunction of ESP8266EX, resulting in the
decrease of overall performance.
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ESP8266EX
Figure 1-8: ESP8266EX RF
1.4.6. External Resistor 12K
An external ground resistor should be connected o ERS12K pin (Pin31). The ground resistor
requires high accuracy when controlling the bias current. An accuracy of 12K ± 1% is
recommended.
Figure 1-9: ESP8266EX External Resistor
1.5. Layout Design
Two layout designs are introduced in this section:
•Standalone ESP8266EX module
•ESP8266EX module as salve device
1.5.1. Standalone ESP8266EX Module
Layout Design
The printed circuit board has four layers:
•The first layer is the TOP layer for signal lines and components.
•The second layer is the GND layer, no signal lines are laid to ensure an entire plain GND
plane.
•The third layer is the POWER layer where only power lines can be placed. It is acceptable to
place some signal lines under unavoidable circumstances.
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ESP8266EX
•The forth lay is the BOTTOM layer. Only signal lines can be laid. It is not recommended to
place components on this layer.
Power Supply Design
3.3 V power lines are highlighted in Figure 1-10. The total width of the power line should be
larger than 15 mil.
Before the power line reaches the analog power-supply pins (including Pin 1, 3, 4, 28, 29) of
ESP8266EX, a 10 μF 0603 or 0603 capacitor (C6 in Figure 10) needs to be added. The
capacitor should be placed adjacent to the analog power-supply pins of the chipset.
Power lines should be placed on the third layer. When the power lines reached the pins of the
chipset, VIAs are needed so that the power lines can go through the layers to connect the pins
of the chipset on the TOP layer. The diameter of the VIA holes should exceed the width of
power lines and the drilling should be a little bit larger than the radius of VIA.
Figure 1-10: ESP8266EX PCB layout
Crystal Oscillator Design
Crystal oscillator should be placed as close to the XTAL pins as possible (without the traces
being too long). It is good practice to add high density ground vias around the clock trace for
great insulation.
There should be no vias on the input and output traces, which means the traces cannot cross
layers. In addition, the input and output traces should not be routed over one another, not
even on different layers.
Place the input and output bypass capacitors on the near left or right side of the chip. Do not
place them on the traces.
Do not route high-frequency digital signal lines in the four-layer board. It is best not to route
any signal line under the crystal oscillator. The larger the copper area on the top layer is, the
better. As crystal oscillator is a sensitive component, do not place magnetic components such
as high current inductance nearby.
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ESP8266EX
Figure 1-11: ESP8266EX crystal oscillators
RF Design
The characteristic impedance that RF lines control is 50 Ω, in order to ensure the complete
board on the second layer. The surrounding drilled hole should be blocked and the lines should
be as short as possible. The width of RF lines should be not less than 6 mil, and above 10 mil is
better.
A π matching circuit near the RF Pin should be reserved in RF lines. RF lines connecting the
chip and antenna should not cover drills, which means cross layer lines are not allowed.
RF lines should not be set at a vertical, or a 45-degree angle. Circular lines are allowed if
necessary. No signal lines of high frequency should be set near RF lines.
RF antenna should be set away from high frequency transmitting devices, such as crystal
oscillators, DDR, and certain high frequency clocks (SDIO_CLK, etc).
Figure 1-12: ESP8266EX RF
1.5.2. ESP8266EX as Slave Device
When ESP8266EX works with other master CPU as a slave device, signal integrity in layout
design is more important than the standalone mode. It is important to keep ESP8266EX away
from the interferences caused by complicity of the system and high frequency signals.
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ESP8266EX
1. UART DOWNLOAD MODE: short this jumper
2. SDIO BOOT MODE: disconnect this jumper
1. Quad (recommend) /Dual SPI flash
2. 8Mbit (recommend)
3. sop-150mill
Figure 1-13: Schematic of ESP8266EX as A Slave Device
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ESP8266EX
Take the mainboard of PAD or TV BOX as an example, following aspects shall be noted in
system design.
Figure 1-14: PCB Plane Layout
As shown in Figure 1-14, ESP8266EX is on the edge of PCB and away from CPU and DDR
which are the noise source interfering with Wi-Fi frequency in the air. The distance between
chipset and CPU + DDR decrease the interference and reduces the coupling noise.
It is suggested to add a 200 Ω series resistor to the six signal lines when ESP8266EX
communicates with CPU via SDIO to decrease the drive current and interference, and also
eliminate the sequence problem caused by the inconsistent length of SDIO lines.
PCB on-board antenna is not recommended as it receives larger interference and coupling
noise which impact RF performance. It is suggested to use external antenna which is directed
away from PCB board via cable and weaken the high frequency interference to Wi-Fi.
The high frequency signal lines between CPU and MEM should be noted. The line layout should
comply with the high frequency signal regulations (refer to the relative documents about DDR
lines layout). CLK and data/addr lines should be lined underground.
The GND of Wi-Fi circuit and other high power devices should be separated and connected
through wires if there are electric machines in system design.
Antenna should keep away from noise source of high frequency, such as LCD, HDMI, Camera
Sensor, USB, etc.
1.5.3. Typical Layout Problems And Solutions
•Q: The current ripple is not large, but the TX performance of RF is rather poor.
Notes:
1. CHIP_PD, as an enable pin, should be connected to a GPIO of Host CPU.
2. Dual SPI Flash (DIO/DOUT): Remove R12, R13, R15 and keep R10, R9.
3. Quad SPI Flash (QIO/QOUT): Remove R9, R10 and keep R13, R12, R15.
a. 1 bit SDIO: No need to connect SD_D2 and SD_D3 to Host.
b. SPI: SD_D3 is reused as SPI_CS and no need to be connected to Host.
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ESP8266EX
Analysis:
Ripple has a strong impact on the performance of RF TX. It should be noted that ripple must
be tested when ESP8266EX sends normal packets. The ripple increases when the power gets
high. Generally, the ripple should be <80 mV when sending 11N MCS7 packets; the ripple
should be < 120 mV when sending 11B packets.
Solution:
Add a 10 μF filter capacitor to the branch of source circuit (ESP8266EX AVDD pin). The 10 μF
capacitor should be adjacent to the VDDA pin.
•Q: The power ripple is small and the TX performance of the chip is poor.
Analysis:
Besides power supply ripple, poor RF TX performance could also be due to the choice of a
wrong crystal. For example, the crystal has low quality-factor or the crystal frequency offset is
too big — when the frequency offset is more than ±40 ppm, ESP8266EX will not work
properly and the performance degrades. Sometimes, the crystal could also be corrupted by
other interfering signals, such as output digital signals or input signals. Another possible issue is
the coupling from inductors or antenna to the crystal. Usually the crystal can filter such
interferers but a large enough amplitude may affect performance.
Solution:
This problem is caused by improper layout and can be solved by re-layout. See Chapter 1.5 for
details.
•Q: When ESP8266EX is sending data packages, the power value tested by an instrument
is much higher or lower than the target power value, and the EVM is relatively poor.
Analysis:
The difference between the power value tested by an instrument and the target power value
can be caused by the impedance mismatch of the chipset RF pin to the antenna.
Solution:
Reserve a π type circuit on the RF wiring which allows match of the resistance with the
antenna, so the resistance from the chipset RF pin to antenna approaches 39-j6 Ω, which
usually gives the best performance.
•Q: TX performance is not bad, but the RX sensitivity is low.
Analysis:
Good TX performance means proper RF impedance matching. External coupling to the antenna
can influence the RX performance. For instance, the crystal oscillator signal’s harmonics could
couple to the antenna. If ESP8266EX serves as slave device, there will be other high frequency
interferers or high speed digital signal interference sources on the board.
Solution:
Keep the antenna away from crystal oscillators and keep RF trace lines away from high
frequency signals.
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ESP8266EX
1.6. Application
1.6.1. Wi-Fi Smart Hardware Converted from UART Serial Ports
The two UART interfaces are defined as Table 1-3.
AT+ instructions relevant documentations are provided with software.
Application example: ESP8266EX development board (see Chapter 2).
1.6.2. Sensor
ESP8266EX can be used in sensor products, using the I2C interface. The I2C works in the
master mode and can connect to multiple sensors. The slave devices is identified through
addressing mode (each slave device has a unique address identity).
The sensor products send the real-time data to ESP8266EX via I2C interface, and ESP8266EX
uploads the data to server wirelessly. Users can acquire information from server through
applications when the mobile phone connects to internet.
1.6.3. Smart Light
ESP8266EX can be used to develop smart home products, such as smart light using PWM and
infrared interfaces. Three PWM interfaces controls red, blue, and green LEDs respectively. The
minimal PWM duty ratio is 1/214. In addition, infrared interfaces allows specific control on LEDs,
such as rest, power on/off, color switch, etc.
1.6.4. Smart Plug
ESP8266EX can be used for developing smart plug products. The GPIOs control the power
switch through the high/low levels switch and connection/disconnection of relay. Such an
application comprises of three modules: 220 V to 3.3 V power conversion module, ESP8266EX
Wi-Fi module and relay control module.
Table 1-3: Pin definitions of UART Interfaces
Category
Pin definition
Function
UART0
(Pin 25) U0RXD+ (Pin 26) U0TXD
Receive and transmit user’s data packages.
UART1
(Pin 14) GPIO2 (U1TXD)
Print information.
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ESP-LAUNCHER
2. ESP-LAUNCHER
2.1. Overview
Espressif provides ESP8266EX development board - ESP Launcher for quick configuration and
further development. The size of the board is 46 mm x 78.5 mm (see Figure 2-1).
Figure 2-1: ESP-LAUNCHER
ESP-LAUNCHER can be configured through USB serial connection or Wi-Fi. The module
functionalities are described in Table 2-1.
7
2
17
11
4
4
1
1 1
1
MISO
MOSI
CS
IO 14
IO 12
IO 13
IO 15
Pin 9
Pin 10
Pin 12
Pin 13
HSPI
Reset key
IO 13
Pin 12
Micro USB
USB UART
Micro USB5 V power
CTS0
TX1
RX0
TX0
IO 13
IO 2
IO 3
IO 1
Pin 12
Pin 14
Pin 25
Pin 26
RTS0IO 15Pin 13
GND
UART
Mode selectIO 0Pin 15
Chip_EnPin 7
R IO 12 Pin 10
G IO 15 Pin 13
B IO 14 Pin 9
W IO 4 Pin 16
PWM
5 V
GND
Relay control IO 15 Pin 13
Transmittor IO 14 Pin 9
Detector IO 5 Pin 24
IR remote control
SD_D2 IO 9
SD_D3 IO 10
SD_CMD IO 11 Pin 20
SD_CLK IO 6 Pin 21
SD_D0 IO 8 Pin 22
SD_D1 IO 7 Pin 23
GND
Deep sleep
wake up
XPD-DCDC
EXT_RSTB
IO 16 Pin 8
Pin 32
TOUTADC_IN Pin 6
I2C
SCLIO 14Pin 9
Pin 14 IO 2 SDA
GND
3V3
3
5
6
8
109
12
13
14
16
18
19
20
21
22
23
24
24
15
25
26
CLK
SDIO / SPI
Pin 19
Pin 18
1
Location hole
8
5 V power switch
15
Relay control
22
Undefined LEDs and keys
2
Reset key
9
IO0 control
16
SMA ANT
23
1.27 mm double pitch
3
Wi-Fi LED, Link LED
10
CH_EN switch
17
Test board
24
2.0 mm double pitch
4
Micro USB: USB-UART, 5 V power
11
Flash2: HSPI
18
Flash1: SPI
25
ADC_IN
5
UART
12
CS of Flash2
19
SDIO/SPI
26
Deep sleep wake up
6
UART SWAP
13
HSPI
20
IR_T, IR_R
7
USB-UART chip
14
3.3 V power
21
I2C
Table 2-1: ESP-LAUNCHER Module Description
Module
Functional description
MICRO USB
interface
Two USB interfaces. Both can be used for 5 V power supply or serial communication (Figure
2-1-4).
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ESP-LAUNCHER
The interfaces on ESP-LAUNCHER are described in Table 2-2.
Power supply
USB interface provides 5 V power supply which can be converted to 3.3 V through DC/CD
converter. One light indicating the power, and a skip stitch for testing the power current.
Slide switch
Three slide switches are used for 5 V power supply (Figure 2-1-8), GPIO0 voltage level switch
(Figure 2-1-9) and chip enable pin CH_EN (Figure 2-1-10). When a switch is pulled up, the voltage
level is high. When a switch is pulled down, the voltage level is low.
Pull up the power switch to power on the board, and pull down the switch to power off the board.
Pull up the GPIO0 switch to enter Flash boot mode. UART debug tool can be used to debug. Pull
down the GPIO0 switch to enter UART Download mode to download software to Flash through
ESP Flash Tool.
Reset Key
SW1 is connected to MTCK (GPIO13) for application reset including reset Wi-Fi configurations
(Figure 2-1-2). SW2 is not defined (Figure 2-1-22).
Indicator
light
Red light (D2) indicates Wi-Fi work status (Figure 2-1-3).
Blue (D3) indicates communication with server (Figure 2-1-3).
Green light (D1) is an indicator light for relay switch control (Figure 2-1-15)
Blue light (D11) and red light (D10) indicate Rx and Tx work status (Figure 2-1-7)
Red light (D12) indicates 5 V power supply (Figure 2-1-8).
D4/13/14/16 are to be defined (Figure 2-1-22).
Jumper
J82: It needs to be short-circuited by a jumper, so 3.3 V power supply can be connected to other
circuits. It can also be used to test power current (Figure 2-1-14).
J3: Chip select for HSPI flash. HSPI flash is disabled when the upper two pins are short-circuited
by a jumper. HSPI flash is enabled when the bottom two pins are shorted circuited by jumper
(Figure 2-1-12).
J14 and J67: Short circuit J14 to connect GPIO13 to U0CTS. Short circuit J67 to connect GPIO15 to
U0RTS (Figure 2-1-6).
J77: Short circuit J77 to connect GPIO16 to EXT_RSTB to awake the device from deep sleep (Figure
2-1-26).
Interfaces
UART, HSPI, SDIO/SPI, I2C, ADC_IN, GPIO16, relay control, PWM and IR TX/RX
Flash
Flash1 (the one mounted on the test board): Flash1 is connected to the chipset using SPI interface.
Currently, Flash1 is mainly used when the chip is working under WiFi standalone mode. R9 and
R85 can be used as chip select of Flash1. By default, Flash 1 is enabled (Figure 2-1-18).
Flash2 (the one mounted on the baseboard): Flash2 is connected to the chipset using HSPI
interface. HSPI is mainly used in SIP mode, in this application, ESP8266EX chipset is used as slave
device, and is connected to the host MCU using the SPI interface that is defined in standard SDIO
interface. HSPI is connected to Flash2. J3 can be used as chip select of Flash2 (Figure 2-1-11).
Testing
modules
There are several modules that can be connected with ESP-LAUNCHER development board for
testing and development, including the test board that is mounted on the baseboard, modules
with1.27mm double-row needles (Figure 2-1-23), and 2.00mm double-row needles.
It should be noted that pins of the modules should be connected with corresponding pins on the
baseboard. Besides, only one type of module can be used at one time.
Module
Functional description
Espressif
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2016.06