Ebyte E104-BT20 User manual

Chengdu Ebyte Electronic Technology Co., Ltd. E104-BT20 User Manual
E104-BT20 User Manual
EDR2.1 Bluetooth Serial Communication Module

Chengdu Ebyte Electronic Technology Co., Ltd. E104-BT20 User Manual
_________________________________________________________________________________________________
Copyright ©2012–2020, Chengdu Ebyte Electronic Technology Co., Ltd.
1
CONTENTS
1. OVERVIEW..............................................................................................................................................................2
1.1 INTRODUCTION..............................................................................................................................................................2
1.2 FEATURES......................................................................................................................................................................2
1.3 APPLICATIONS............................................................................................................................................................... 2
2. PARAMETERS.........................................................................................................................................................3
2.1 LIMIT PARAMETERS.......................................................................................................................................................3
2.2 WORKING PARAMETERS................................................................................................................................................ 3
3. SIZE AND PIN DEFINITION................................................................................................................................ 4
5. WORKING MODE.................................................................................................................................................. 6
5.1 CONFIGURATION MODE (MODULE ENTERS AT MODE)...................................................................................................6
5.2 WORKING ROLE CHANGING..........................................................................................................................................6
5.3 MAC ADDRESS BINDING............................................................................................................................................... 7
5.4 STATUS PRINTING..........................................................................................................................................................7
5.5 IO PINS..........................................................................................................................................................................7
5.6 DATA TRANSCEIVING.................................................................................................................................................... 7
6. AT COMMAND........................................................................................................................................................ 7
6.1 DEFAULT PARAMETERS:................................................................................................................................................7
6.2 AT COMMAND DETAILS:................................................................................................................................................8
6.2.1 TEST COMMAND.........................................................................................................................................................8
6.2.2 MODULE RESETTING..................................................................................................................................................8
6.2.3 RESTORE DEFAULT STATE..........................................................................................................................................9
6.2.4 OBTAIN SOFTWARE VERSION NUMBERS.....................................................................................................................9
6.2.5OBTAIN BLUETOOTH ADDRESS................................................................................................................................... 9
6.2.6 INQUIRY/SETTINGS-DEVICE NAME.............................................................................................................................9
6.2.7 INQUIRY/SETTING-BLUETOOTH ROLE...................................................................................................................... 10
6.2.8 INQUIRY/SET-SERIAL PORT PARAMETERS................................................................................................................10
6.2.9 INQUIRY/SETTINGS-CONNECTION MODE................................................................................................................. 11
6.2.10 INQUIRY/SETTING-BIND BLUETOOTH ADDRESS.....................................................................................................11
6.2.11 INQUIRY/SETTING-PAIRING CODE..........................................................................................................................12
7. QUICK USE............................................................................................................................................................19
8. NOTICE FOR HARDWARE................................................................................................................................19
9. FAQ.......................................................................................................................................................................... 20
9.1 COMMUNICATION RANGE IS TOO SHORT..................................................................................................................... 20
9.2 MODULE IS EASY TO DAMAGE.....................................................................................................................................20
9.3 BER (BIT ERROR RATE)IS HIGH................................................................................................................................ 21
10. SOLDERING GUIDANCE................................................................................................................................. 21
10.1 REFLOW SOLDERING TEMPERATURE.........................................................................................................................21
10.2 REFLOW SOLDERING CURVE......................................................................................................................................22
11. PACKAGE FOR BUCK ORDER...................................................................................................................... 22
REVISION HISTORY............................................................................................................................................... 23
ABOUT US..................................................................................................................................................................23

Chengdu Ebyte Electronic Technology Co., Ltd. E104-BT20 User Manual
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1. Overview
1.1 Introduction
E104-BT20 Bluetooth serial communication module is a data transmission
module based on Bluetooth Specification V2.1 BR / EDR Bluetooth protocol.
The working frequency is 2.4GHz ISM, and the modulation method is GFSK.
The module's maximum transmission power is 3dBm. It’s packaging method is stamp hole and It has onboard PCB
antenna which enable the module to have a 50-meter communication distance.
The E104-BT20 module integrates the transparent transmission function and the master-slave function and it’s
offers instant access to user. The E104-BT20 supports AT instruction, so users can set parameters such as module
master-slave role, serial port baud rate, device name, etc., which is flexible and convenient to use. It also supports
point-to-point connection from master to slave module to achieve fast data transmission and the data transmission
is stable and efficient. In slave mode, it supports a maximum baud rate of 921600bps. It is a simple and efficient
data transmission module that minimizes the developer's work and project development time.
1.2 Features
Bluetooth Specification V2.1 + EDR protocol;
BR / EDR master-slave integration available;
AT instruction configuration available;
Simple and secure pairing SSP and compatible with PIN pairing;
SPP transparent transmission;
High-speed continuous transmission;
The host connection automatically;
GPIO input/output control;
900 bytes of serial cache
Effective communication distance 50 meters
Support license-free global ISM 2.4GHz frequency band;
Built-in PCB onboard antenna, no external antenna required.
1.3 Applications
Bluetooth wireless data transmission
Wireless meter reading and wireless sensing
Smart home, industrial control
Industrial remote control and telemetry
Smart buildings, smart buildings
Automated data acquisition
Health sensor
Automotive testing equipment
smart robot

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2. Parameters
2.1 Limit Parameters
Main Parameters
Value
Remarks
Min.
Max
Input Voltage(V)
0
3.6
Permanent damage occurred when voltage is over 3.6V
Blocking Power(dBm)
-
10
Low chance to be damaged for short-distance transceiving
Working Temp.(℃)
0°C
+85
-
2.2 Working Parameters
Main Parameters
Value
Remarks
Min.
Typical
Max.
Working Voltage(V)
3.0
3.3
3.6
Voltage above 3.3V can guaranty Max TX power
Tx Electrical Level(V)
-
3.3
-
5V TTL could cause permanent damage
Working Temp (℃)
0℃
-
+70℃
-
Working Frequency (MHz)
2402
-
2480
Support ISM Chanel
Power
Consumption
TX Current(mA)
-
72.5
-
-
RX Current(mA)
-
70
-
-
Max TX Power(dBm)
-
3
-
-
RX Sensitivity(dBm)
-
-89
-
-
Arbitrary IO
VIL/VIH
-/1.75V
-
1.5V/-
-
VOL/VOH
-/VCC-0.25
-
GNG+0.25/-
-
Connection Current
(slave module)
-
54.4
-
mA

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Parameters
Value
Remarks
Reference distance
50m
Clear and open environment, antenna height 2.5m
Launch length
300Byte
-
Bluetooth protocol
Bluetooth Specification V2.1+EDR
-
Communication Interface
UART
-
Packaging type
SMD
-
Interface method
1.27mm
-
Dimensions
13*25mm
-
product weight
1.2±0.1g
-
Antenna interface
PCB Antenna
Equivalent impedance about 50Ω
3. Size and pin definition
No
Name
Direction
Function
Remark
1
GND
-
Power Supply Ground
Ground, connected to the power reference ground
2
SWDIO
Input/Output
-
Inputting and outputting data
3
P_LED
-
-
-
4
SWCLK
Input
-
Clock input
5
GPIO1
Suspension
Universal IO
Pin for User configuration
6
GPIO2
Suspension
Universal IO
Pin for User configuration

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7
LINK
Output
LED indicator
Module connection indicator Output pin②
8
MOD
Input
modification
Input high level, the module enters configuration mode, input low level, the module enters
transparent transmission mode
9
MCU_MOD
E
Input
-
(This pin has internal pull-down, and works in transparent transmission mode by default)
10
GND
-
Power Supply Ground
High level enters online programming mode, low level is working mode
11
GPIO3
Suspension
Universal IO
Ground, connected to the power reference ground
12
GPIO4
Suspension
Universal IO
Pin for User configuration
13
GPIO5
Suspension
Universal IO
Pin for User configuration
14
GPIO6
Suspension
Universal IO
Pin for User configuration
15
RESETB
Input
Module reset pin
(RST)
Pin for User configuration
16
GND
-
Power Supply Ground
The low-level input module enters the hardware reset state, and the high-level input
module returns to the normal working state. This function is used for reset operation in
emergency
17
GND
-
Power Supply Ground
Ground, connected to the power reference ground
18
VCC
Input
3.3V
Ground, connected to the power reference ground
19
GND
-
Power Supply Ground
Power Supply Input
20
GPIO7
Suspension
Universal IO
Ground, connected to the power reference ground
21
CTS
Input
Hardware flow control
Pin for User configuration
22
STATUS
Output
LED indicator
UART clear transmit input pin
23
TXD
Output
TX Power Ground
Module status indicator Output pin①
24
RTS
Output
Hardware flow control
Module external output serial data
25
RXD
Input
RX Serial Port
UART request send input pin
26
GND
-
Power Supply Ground
Module receives external serial data
Note 1: Following the AT + POLAR setting instruction, the module status indicator output pin defaults to output a high level to light
up the LED.
Normal configuration mode (MOD pin is low level, then power on the module, the baud rate is same with the one from last power off.,
the default value is 9600bps)
Before the host is connected,
Fast flashing: when the master does not record the slave address;
Slow flashing: when recording slave address;
After connecting, two flashes and one stop.
Slave / Slave Loopback
Flashes quickly before connecting;
After connecting, two flashes and one stop;
Power-on configuration mode (set MOD pin high first, then power on the module, baud rate is fixed at 38400bps)
The LED keeps lighting up every 2 seconds for 1 second at whole process.
Note 2: Following AT + POLAR setting instructions, the output pin of the module's connection indicator defaults to light up the LED
by outputting a high level.
Before connecting,
The LED is off.
Once connected,
The LED light is always on

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5. Working Mode
5.1 Configuration mode (module enters AT mode)
There are two configuration modes: normal configuration mode and power-on configuration mode.
In normal configuration mode, pull the MOD pin low before the module is powered on (the default setting is pull
down). After the module is powered on, set the MOD pin high again to enter the AT command mode. The parameters of
the serial port are the values successfully set by the user before the last power-off (the default value is 9600bps, 1 stop bit,
no parity bit). Now, the user can operate all AT commands; after Bluetooth connection, it will automatically enter the
transparent transmission mode. If the user needs to set the MOD pin high again to enter the AT command mode where the
module can’t receive data from other modules. If the MOD pin is set low, it will exit the AT command mode and return to
the transparent transmission mode. After disconnecting, the module is in AT command mode, and user can continue the
inquiry/setting operation. If the user forgets the baud rate or gets a module that has been set with certain parameters, user
can set the module to enter the power-on configuration mode and reset the baud rate.
NOTE: Some instructions are only available under certain mode, such as: CONNECTED mode or MASTER mode.
Details will be given in Chapter 6.
Power-on configuration mode. Setting the MOD pin high and the module will immediately enter the AT command
mode after power-on. The status light will keep flashing slowly. In this mode, the module will not enter the connection
state. The other parameters are the same as the values saved since the last power-off. After setting the baud rate, restarting
the module and entering the normal configuration mode to use the new baud rate. All commands are available except for
"AT + LINK", "AT + RNAME", "AT + RSSI", and "AT + DISC" .
5.2 Working Role Changing
The module can be configured into three working roles: master, slave, and loopback. The master role supports the
automatic connection function; the slave and slave loopback support passive connection; the slave loopback can receive
data from the peer Bluetooth master device and return the data to the peer Bluetooth as is.
Steps to switch module roles:
Firstly, Enter the module's AT instruction mode
Secondly,. Use the serial port debugging assistant, send the AT command "AT + ROLE = <param>", and use the Enter
key to change the line. For details, see the AT command section. If the communication is successful, it returns "OK" and
the module role is still the original working role.
Thirdly, Set the MOD pin to low level and power on again to enter the normal configuration mode. At this time, the
module's working role takes effect.

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5.3 MAC address binding
The AT + ROLE = 1 command sets the module to the master working role. AT + CMODE = 0 sets the connection mode
to the specified Bluetooth address connection. AT + BIND = [MAC] binds the MAC address. When the module is
powered on again, it will try to connect to this address until it succeeds. After disconnecting, it will not initiate a
connection. Do not set the bound Bluetooth address to zero which is invalid.
5.4 Status Printing
When Bluetooth is connected or disconnected, the module status information is printed through the serial port, as shown
in the following table.
Status
Printed Information
Connection On
+CONNECTED:SUCCESS OK
Connection off
+DISC:SUCCESS OK- Disconnection
5.5 IO Pins
In order to facilitate users to expand the IO port pin functions of the module and diversify the module functions, this
module has a total of 8 IOs. Users can configure IO as universal input or output. The output pin can be configured as an
output low level or an output high level, and the input pin can be configured as a pull-up or pull-down; please refer to
Chapter 6 AT command “AT + PIO”, “AT + MPIO”, “AT + PII "," AT + MPII ", etc.
5.6 Data Transceiving
At baud rate of 115200bps/s or 460800bps/s, the module supports serial port to send 200K files continuously without
packet loss.
6. AT Command
6.1 Default Parameters:
Default Parameters
Equipment name
E104-BT20
version number
Ebyte.com V1.0
Check Digit
NONE
Stop bit
1
Baud rate
9600
MAC binding address
00:00:00:00:00:00
Pairing code
1234
Bluetooth role
Slave

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Connection mode
Specify the Bluetooth address connection mode
LED drive polarity
Low level
GPIO pins
Suspended
6.2 AT command Details:
Command format
1. The "AT +" instruction is based on the ASCII character set, and the instruction has a strict format.
< >: The actual instruction does not include these two characters, it is only used to indicate the enclosed, and must be
included in the instruction.
2. AT instruction format
<AT + CMD>, <op>, <param1, param2, param3, ...>, <CR> <LF>
<AT + CMD>:AT +: command message prefix; CMD: command string
<op> Instruction operation character, =: Set operation; ?: Represents a query operation
<param-n>: parameter list of setting operations, all separated by commas
<CR> <LF>: terminator, which means carriage return and line feed, ASCII codes are 0x0a and 0x0d
3. Response message
Query operation <+ CMD:> <param1, param2, param3 ...> <CR> <LF> <OK> <CR> <LF>
+: Response message prefix
CMD: command string
(NOTE: The interval symbol between the parameters does not change according to the instruction. The returned Bluetooth
address is separated by a colon ’:’)
Setting operation <OK> <CR> <LF> —success,<FAIL> —failure
Incorrect command input response format: <+ ERROR (error code index number)> <CR> <LF>
<CR> <LF>: terminator, which means carriage return and line feed, ASCII codes are 0x0d and 0x0a
4. The letter in <AT + CMD> command is not case sensitive.
6.2.1 Test Command
Command
Answer
Parameter
AT
OK
None
6.2.2 Module Resetting
Command
Answer
Parameter
AT+RESET
OK
None
NOTE: Before sending this command, please pay attention to the MOD pin status. If MOD is low, it will enter the
normal configuration mode, otherwise, it will enter the power-on configuration mode.

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6.2.3 Restore Default State
Command
Answer
Parameter
AT+RESTORE
OK
None
NOTE: See section 6.1 Default parameters.
6.2.4 Obtain Software Version Numbers
Command
Answer
Parameter
AT+VERSION?
+VERSION:<param]>OK
param:software version number
For Example:
Command: AT + VERSION?
Answer: + VERSION: ebyte.comV1.0
OK
6.2.5Obtain Bluetooth Address
Command
Answer
Parameter
AT+ADDR?
+ADDR:<param>
param:Bluetooth Address
For Example:
Command:AT+ADDR?
Answer: +ADDR:00:00:00:00:00:00
OK
6.2.6 Inquiry/Settings-Device Name
Command
Answer
Parameter
AT+NAME?
OK
param:蓝牙设备名称
出厂名称: “BT-20”
AT+NAME=<param>
+NAME :<param>OK
For Example:
Command:AT+NAME=E104-BT20
Answer:OK
Command:AT+NAME?
Answer:+NAME: E104-BT20
OK

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6.2.7 Inquiry/Setting-Bluetooth Role
Command
Answer
Parameter
AT+ROLE?
OK
param: The values are as follows
0—Slave default
1—Master
2—Slave-Loop
AT+ ROLE =<param>
+ ROLE :<param>OK
The above commands will take effect after restarting.
Module role description:
Slave—Passive connection;
Slave-Loop—Passive connection, receiving data from the peer Bluetooth master device and returning the data to the peer
Bluetooth master device as is;
Master role (Master) —In the specified Bluetooth address connection mode, the Bluetooth address that is bound is automatically
connected; the Bluetooth address in the pairing list is automatically connected to realize the transparent transmission of data between
the master and slave Bluetooth devices.
6.2.8 Inquiry/Set-Serial Port Parameters
Command
Answer
Parameter
AT+UART?
OK
param1: baud rate (bits / s)
The values are as follows
(decimal):
2400, 4800, 9600, 19200, 38400,
57600, 115200, 230400, 460800,
921600
param2: stop bit
0—1 bit
2 to 2
param3: check digit
0—No parity
1—even parity
AT+ UART =<param>
+ UART :< param1>,
< param2>,< param3>
OK

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2—odd parity
Default setting: 9600,0,0
The above commands will take effect after restarting.
For example:
Setting serial port parameters: 115200, 2 stop bits, even parity
Command:AT+UART=115200,1,2
Answer:OK
Command:AT+UART?
Answer:+UART:115200,1,2
6.2.9 Inquiry/Settings-Connection Mode
Command
Answer
Parameter
AT+CMODE?
OK
param:
Specify the Bluetooth address
connection mode
(The specified Bluetooth address is
set by the binding instruction)
1—Any Bluetooth address
connection mode
2—Slave-Loop
Default connection mode: 0
AT+CMODE=<param>
+ CMODE:<param>OK
The above commands will take effect after restarting.
6.2.10 Inquiry/Setting-Bind Bluetooth Address
Command
Answer
Parameter
AT+BIND?
OK
param: bind Bluetooth address
Bluetooth address binding by
default:00:00:00:00:00:00
AT+ BIND =<param>
+ BIND:<param>OK
Host role, in the specified Bluetooth address connection mode, the bound address is automatically connected. If the default
address is zero, the address will not be connected at this time.
for example:
Set binding Bluetooth address: 11: 22: 33: 44: 55: 66
Command: AT + BIND = 11,22,33,44,55,66
Answer: OK
Command: AT + BIND?
Answer: + BIND: 11: 22: 33: 44: 55: 66
OK

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6.2.11 Inquiry/Setting-Pairing Code
Command
Answer
Parameter
AT+PSWD?
OK
param: pairing code
Default: 1234
AT+ PSWD =<param>
+ PSWD:<param>OK
6.2.12 Inquiry/Set LED Indication Drive and Connection Status Output Polarity
Command
Answer
Parameter
AT+POLAR?
OK
param1: The values are as follows
0—STATUS PIN output low level LED
1—STATUS PIN output high level light LED
param1: The values are as follows
0—LINK PIN output low level light LED
1—LINK PIN output high level light LED
Default setting: 0,0
AT+ POLAR =
<param1>,<param2>
+ POLAR:<param1>,
<param2>
OK
The STATUS pin drives the LED to indicate the module's working status; the LINK pin indicates the connection status.
for example:
Set the STATUS output low to light the LED, and the LINK output high to indicate that the connection was successful.
Command: AT + POLAR = 0,1
Answer: OK
Command: AT + POLAR?
Answer: + POLAR: 0,1
OK
6.2.13 Set GPIO single port output
Command
Answer
Parameter
AT+ PIO =<param1>,
<param2>
OK
param1: GPIO port number (decimal number)
param2: GPIO port output level
0—low
1—high
For Example:
1.GPIO1 pin output high level
Command: AT + PIO = 1,1
Answer: OK
2.GPIO1 pin output low level
Command: AT + PIO = 1,0
Answer: OK

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6.2.14 Setting GPIO multi-port output
Command
Answer
Parameter
AT+ MPIO =<param>
OK
param1: GPIO port sequence mask
combination (one byte-decimal number)
The module provides users with 7 IO port, GPIO1 ~ GPIO7, users can use to expand the input and output ports. The multi-port
output setting sets all pins to output mode.
GPIO serial number mask = (1 << GPIO serial number)
GPIO serial number mask combination = (GPIO serial number mask 1 | GPIO serial number mask 2 | ……)
Such as:
GPIO1 mask = (1 << 1) = 0x02
GPIO5 mask = (1 << 5) = 0x20
GPIO1 and GPIO5 mask combination = (0x010x20) = 0x22
for example:
1. GPIO1 and GPIO5 output high level, and the rest output low level
Command: AT + MPIO = 21
Answer: OK
2. GPIO3 outputs high level and the rest outputs low level
Command: AT + MPIO = 08
Answer: OK
3. GPIO7 outputs high level and the rest outputs low level
Command: AT + MPIO = 80
Answer: OK
4.All pins output low level
Command: AT + MPIO = 00
Answer: OK
6.2.15 Setting single GPIO input
Command
Answer
Parameter
AT+ PII =<param1>,
<param2>
OK
param1: GPIO port number (decimal number)
param2: GPIO port input
0—pull up
1—Drop down
6.2.16 Setting single multiple GPIO input
Command
Answer
Parameter
AT+ MPII =<param>
OK
param: GPIO port sequence mask
combination (hexadecimal number)
The multi-port input setting sets all pins to input mode.

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for example:
1. GPIO1 and GPIO5 pull-down inputs, and the remaining pull-up inputs
Command: AT + MPII = 22
Answer: OK
2. GPIO3 outputs high level and the rest outputs low level
Command: AT + MPIO = 08
Answer: OK
3. GPIO7 outputs high level and the rest outputs low level
Command: AT + MPIO = 80
Answer: OK
4.All pins output low level
Command: AT + MPIO = 00
Answer: OK
6.2.17 Querying GPIO Port Status
Command
Answer
Parameter
AT+MPIO?
+ MPIO:<param>OK
param: GPIO port value (8bits)
param [bit 0] is invalid
param [bit 1] = GPIO1
...
param [bit 7] = GPIO7
If GPIOX is output
0—low
1—high
If GPIOX is input
0—pull up
1—Drop down
The module provides users with IO port resources, a total of 8, GPIO0 ~ GPIO7, users can use to expand input and
output ports.
6.2.18 Remove all authenticated devices from the Bluetooth pairing list
Command
Answer
Parameter
AT+RMAAD
OK
None
For Example:
Command:AT+RMAAD
Answer:OK

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6.2.19 Removes the specified authenticated device from the Bluetooth pairing list
Command
Answer
Parameter
AT+RMSAD=<param>
OK—Success
FAIL—Failed
param: Bluetooth device address
For Example:
Delete the device with Bluetooth address 11: 22: 33: 44: 55: 66 from the pairing list. The input Bluetooth address cannot
be zero, otherwise the command format is wrong.
Command: AT + RMSAD = 11: 22: 33: 44: 55: 66
Answer: OK—Successfully deleted
Or FAIL—No Bluetooth device with address 11: 22: 33: 44: 55: 66 exists in the pairing list
6.2.20 Find the specified authenticated device from the Bluetooth pairing list
Command
Answer
Parameter
AT+FSAD=<param>
OK—Success
FAIL—Failed
param: Bluetooth device address
For Example:
Find the Bluetooth device with the address 11: 22: 33: 44: 55: 66 from the pairing list. The input Bluetooth address
cannot be zero, otherwise the command format is wrong.
Command: AT + FSAD = 11,22,33,44,55,66
Answer: OK—A Bluetooth device with the address 11: 22: 33: 44: 55: 66 exists in the pairing list.
Or FAIL—The Bluetooth device with the address 11: 22: 33: 44: 55: 66 does not exist in the pairing list.
6.2.21Inquiring the number of authenticated devices in the Bluetooth pairing list
Command
Answer
Parameter
AT+ADCN?
+ ADCN:<param>OK
param: number of devices in the pairing list
For Example:
Command: AT + ADCN?
Answer: + ADCN: 0
OK—No Bluetooth devices in the pairing list
6.2.22 Get the recently used Bluetooth certified device address
Command
Answer
Parameter
AT+MRAD?
+ MRAD:<param>OK
param: the address of the recently
connected Bluetooth device
for example:

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Command: AT + MRAD?
Answer: + MRAD: 00: 00: 00: 00: 00: 00
OK—No Bluetooth connection has been established recently
6.2.23 Inquiring peer RSSI signal strength (valid in connected state)
Command
Answer
Parameter
AT+RSSI?
+ RSSI:<param>OK
param: signal strength
Only valid after the module has established a connection.
for example:Command:AT+RSSI?
Answer:+RSSI:-26
OK
6.2.24 Disconnect (available when connected)
Command
Answer
Parameter
AT+DISC
+ DISC: SUCCESS
OK—Disconnect successfully
None
6.2.25 Connect device (available as host role)
Command
Answer
Parameter
AT+LINK=<param>
OK—success
FAIL—Failure
param: remote device Bluetooth address
Use the AT command to establish a connection with the slave under the master role.
for example:
Establish a connection with the slave Bluetooth device: 11: 22: 33: 44: 55: 66
Command:AT+LINK=11,22,33,44,55,66
Answer:+CONNECTED SUCCESS
OK
6.2.26 Inquiring Bluetooth module working status
Command
Answer
Parameter
AT+STATE?
+ STATE:<param>OK
param:Module working status
“READY”
“PAIRABLE”
“AUTO CONNECT”
“CONNECTED”
“DISCONNECTED”
“UNKNOWN”

Chengdu Ebyte Electronic Technology Co., Ltd. E104-BT20 User Manual
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For Example:
Command:AT+STATE?
Answer:+ STATE:PAIRABLE
OK—Waiting to be connected
6.2.27 Inquiring/Set: Inquiring scan, page scan parameters
Command
Answer
Parameter
AT+PISCAN?
OK
param1: query interval
param2: query duration
param3: paging interval
param4: paging duration
The above parameters are all
decimal numbers
Default (ms):
768, 256, 768, 256
AT+PISCAN=<param1>
,<param2>,<param3>,
<param4>
+ PISCAN:<param1>,
<param2>,<param3>,
<param4> OK
Query time interval (cannot be odd, otherwise error code 1 is returned), paging interval ranges from 18 to 4096, query duration
and paging duration ranges from 17 to 4096, and the query interval must be greater than or equal to For query duration, the
paging interval must also be greater than or equal to the paging duration (otherwise an error code 1 is returned).
for example:
Take the default value as an example
Command:AT+PISCAN=768,256, 768, 256
Answer:OK
Command:AT+PISCAN?
+PISCAN:768,256,768,256
OK
6.2.28 Obtaining the remote Bluetooth name (valid in the connected state)
Command
Answer
Parameter
AT+ RNAME?
+ RNAME:<param>OK
param:Remote Bluetooth name
For Example:
Take the default value as an example
Command:AT+RNAME?
Answer:+RNAME:HUAWEI P10
OK
6.3 AT Command error code description
Error code return form—ERROR (error code index number)
Error code index number(Decimal)
Description

Chengdu Ebyte Electronic Technology Co., Ltd. E104-BT20 User Manual
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Copyright ©2012–2020, Chengdu Ebyte Electronic Technology Co., Ltd.
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0
AT command error
1
Parameter format error
2
Device name is too long (more than 40 bytes)
3
Device name length is zero
4
Bluetooth role is invalid
5
Invalid baud rate
6
Stop digit is invalid
7
Check digit is invalid
8
Invalid connection mode
9
The pairing code is longer than 16 bytes
10
Pairing code length is zero
11
Drive polarity parameter is out of range
12
GPIO port number is out of range
13
Output status or up-down parameters are out of range
14
MPI0, MPII parameters exceed one byte (length is zero)
15
Bluetooth address is longer than 12 bytes
16
Bluetooth address is 0
17
Authentication device does not exist in the pairing list
18
Query scan and page scan parameters are out of range
19
Power-on configuration mode does not support
connection-related instructions
20
No connection established

Chengdu Ebyte Electronic Technology Co., Ltd. E104-BT20 User Manual
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Copyright ©2012–2020, Chengdu Ebyte Electronic Technology Co., Ltd.
19
7. Quick Use
7.1 Enter AT command mode
Connect the Bluetooth module E104-BT20 to the USB interface of the PC, and open the serial port debugging assistant on the PC
side to debug the module.
First, the AT test instruction. After ensuring that the MOD pin is set low (the default is low), the module is powered on, and then
the MOD pin is set high to enter the AT instruction mode. When sending the command, the serial port debugging assistant should
select "enter key line feed" and set the serial port parameter baud rate 9600bps, 1 stop bit, no parity check. If the command AT is sent,
it returns OK. Then the module successfully enters the AT instruction mode and can use other AT instructions.
7.2 Auto Connection
Module default parameters: Specify connection mode, slave role, baud rate 9600bps, 1 stop bit, no parity. When the module is
powered on, it is a slave role. Enter the AT command mode and send "AT + ADDR?" To query the Bluetooth module address to
facilitate the host connection.
Set another module to enter the AT command mode, set the baud rate of the serial tool to 9600bps, and send the command "AT +
ROLE = 1". If successful, it will return OK. Assume that the slave address is 11: 22: 33: 44: 55: 66, because the default mode is
"Specify Bluetooth connection mode", you only need to set the binding Bluetooth address to the slave's Bluetooth address to
automatically connect the slave, Send the command "AT + BIND = 11,22,33,44,55,66". If it returns OK, the setting is successful.
Restart the module. At this time, the module as the master has taken effect. After the host is powered on, it will automatically establish
a connection with the slave.
8. Notice for Hardware
It is recommended to use DC stabilized power supply. The power supply ripple factor should be as small as possible, and
the module should be reliably grounded.
Please ensure that the positive and negative poles of the power supply are properly connected. If the reverse connection is
made, the module may be permanently damaged.
Please ensure the power supply voltage is within the working voltage range. If the maximum voltage is exceeded, the
module will be permanently damaged.
Please check the stability of the power supply, and the voltage cannot be fluctuated frequently;
When designing the power supply circuit for the module, it is recommended to reserve more than 30% of the margin to
achieve long-term stable operation of the system;
The installation location of the module should be as far away as possible from the power supply, transformers,
high-frequency wiring and other parts with large electromagnetic interference;
High-frequency digital routing, high-frequency analog routing, and power routing must avoid module locations. If the
wiring must pass under the module, assuming that the module is soldered to the Top Layer, the area where the module is in
contact with the Top Layer should be covered with copper (all copper is well grounded), and the area must be close to the digital