WAVESHARE ELECTRONICS Pico-BLE Dual-Mode Bluetooth-compatible 5.1 Expansion Module

Product description

The Pico-BLE is a dual-mode Bluetooth 5.1 expansion module designed for Raspberry Pi Pico, which is controlled via UART AT commands, with SPP and BLE support. Combined with the Raspberry Pi Pico, it can be used for Bluetooth wireless communication applications.

Product parameters

Category	Parameter
BLUETOOTH MODULE	Dual-mode Bluetooth to UART module
DIMENSIONS(mm)	56.5 x 21
TRANSMISSION DISTANCE	30m (open-air)
COMMUNICATION	UART
ANTENNA	Onboard PCB antenna
INPUT VOLTAGE	5V/3.3V
OPERATING CURRENT	Startup transient current: about 25mA for about 300ms; Stable status current: about 6mA, nonlow power mode; Low power mode current: refer to user manual
TRANSMISSION CACHE	1K bytes UART cache, it is recommended to transmit less than 512 bytes per transmission for SPP
UART BAUDRATE	13 different baud rate configuration, 115200 bps by default
OPERATING TEMPERATURE	-40℃ ~ 80℃

Function pin	Description
VSYS	3.3V/5V Power
GND	GND
GP0	UART transmit pin (default)
GP1	UART transmit pin (default)
GP4	UART transmit pin (default)
GP5	UART transmit pin (default)
GP15	Bluetooth connection status detection pin (high level means Bluetooth is connected)

Hardware connection

Direct connection:

Extended version connection:

Product use

Communication format

Support asynchronous serial communication mode, accept commands sent by the host computer through the serial port Communication Standard:115200 bps — Users can set through serial port commands, see: Module baud rate setting and query     Data bits: 8   Stop bits: 1    Parity bits: none   Flow control: none Note: The design of all instructions is regular, not randomly divided, you can find the rules by comparing the following
Control command format: AT+<CMD>[<param>]\r\n    —- All are characters, not hex numbers
Data Feedback Format:：<IND>[<param>]\r\n
Data characteristics	Detailed description
AT+	The control command is the control command given by the control host to the module, starting with “AT+”
<CMD>	Followed by <CMD> control, usually 2 characters
[<param>]	If there is a parameter after CMD, it is followed by [<param>]
\r\n	Finally, it ends with “\r\n”, the character type is linefeed, and windows is the enter key. 0x0D, 0x0A in hex
<IND>	1、Data feedback is that Bluetooth feeds back various status and data information to the host, starting with <IND>

A brief introduction to commands
Functional	Command	Remark
Common  Command Features	AT+C?	The public command starts with AT+C, followed by “?” is the detailed function command
Bluetooth Command Features	AT+B?	The Bluetooth command starts with AT+B, followed by “?” is the detailed function command
Public inquiry	AT+Q?	The public query command starts with AT+Q, followed by “?” is the
Bluetooth query command	AT+T?	The Bluetooth query command starts with AT+T, followed by “?” is the detailed function command

Communication command example

Common Part–Control Instructions–Description
CMD	Corresponding function	Detailed description
AT+CT	Set baud rate	For detail see: Module baud rate setting and query
AT+CZ	Chip reset	Chip soft reset, see: Reset and restore factory
AT+CW	Chip reset to factory settings	Restore factory settings, clear all previously memorized parameters, see: Module reset and restore factory settings
AT+CL	Chip low power settings	See Chip low-power command description, the default is the normal working mode
AT+CR	Chip power-on callback information settings	See: Chip power-on callback information setting, the default is open
AT+BM	Set BLE Bluetooth name	See: Set the name and address of Bluetooth
AT+BN	Set the MAC address of BLE	See： Set the name and address of Bluetooth
AT+BD	Set SPP Bluetooth name	See： Set the name and address of Bluetooth
AT+QT	Query the baud rate of the	See： Module baud rate setting and query
AT+QL	Query the low-power state	See: Set the name and address of Bluetooth
AT+TM	Query BLE Bluetooth name	See: Set the name and address of Bluetooth

AT+TN	Query BLE Bluetooth	See: Set the name and address of Bluetooth
AT+TD	Query SPP Bluetooth name	Seel: Set the name and address of the Bluetooth

Module baud rate setting and query

AT+CT??\r\n		Baud rate setting command, ?? represents the serial number of the baud rate
AT+QT\r\n		Baud rate query command, return QT+?? ?? represents the serial number of the baud rate
Baud rate serial number
01	02		03	04	05	06	07
9600	19200		38400	57600	115200	256000	512000
08	09		10	11	12	13
230400	460800		1000000	31250	2400	4800

 

1. Once the baud rate is set, the chip will memorize it. The next time you turn it on, the baud rate will be the one you set.
2. After setting the baud rate, please wait for 1 second, then send the reset [AT+CZ], or power off.
3. If you want to restore the default baud rate, please send the command to restore the factory settings, then the chip will automatically erase all configurations.

Module reset and factory reset

Reset command： AT+CZ\r\n
Please wait one second after entering the reset command

Factory reset command： AT+CW\r\n
Please wait five seconds after entering the factory reset command

Set the name and address of the Bluetooth

AT+BMBLE-Waveshare\r\n	Set BLE Bluetooth name to “BLE-Waveshare”
AT+BN112233445566\r\n	Set the address of BLE. The address displayed on the mobile phone is: 66 55 44 33 22 11
AT+BDSPP-Waveshare\r\n	Set the SPP Bluetooth name to “SPP-Waveshare”

1. After setting the Bluetooth name, please reset the module, and use the mobile phone to search again after reset.
2. The maximum length of the Bluetooth name is 30 bytes
3. After modifying the Bluetooth name, if the device name displayed on the mobile phone does not change, the main reason may be that you have not modified the Bluetooth address, resulting in the mobile phone not being updated synchronously. At this time, what you need to do is to change the pairing information on the mobile phone. Delete and search again, or search with another device.

Query the name and address of Bluetooth

AT+TM\r\n	Return TM+BLE-Waveshare\r\n for Bluetooth   name BLE-Waveshare
AT+TN\r\n	Returns the Bluetooth address of TN+12345678AABB\r\n  BLE: 0xBB, 0xAA, 0x78, 0x56, 0x34, 0x12
AT+TD\r\n	Return to TD+SPP-Waveshare\r\n for Bluetooth name SPP-Waveshare

There is no SPP address whether it is set or queried, because the SPP address is obtained by +1 on the
highest byte of the BLE MAC address, for example:
The address of BLE is returned as: TN+32F441F495F1,
This means the address of BLE is: 0xF1 , 0x95 , 0xF4 , 0x 41 , 0xF4 , 0x32
Then the address of SPP is: 0xF2 , 0x95 , 0xF4 , 0x 41 , 0xF4 , 0x32

Chip low power instruction description

AT+CL00\r\n	Do not enter low power mode. It will be valid at the next power-on. Be careful to restart the power after setting
AT+CL01\r\n	Enter low power mode. It is valid at the next power-on. After setting, pay attention to power on again — the chip enters this state by default, no need to set
AT+QL\r\n	Low-power query command. The return value is QL+01\r\n, indicating that the current working state is low power consumption mode

1. After setting, you need to power on again to update the configuration
2. This command is memorized. After the command is sent successfully, the chip will save it.
3. After starting the low-power mode, there are many restrictions, which are generally turned off by default.
4. After the setting, the chip will return to the device information normally when it is powered on. AT commands can be set within 5 seconds, and after 5 seconds, any AT commands will be ignored before the Bluetooth connection.
5. The difference between low power consumption and normal operation is mainly due to the difference in the way of Bluetooth broadcasts when Bluetooth is not connected. During normal operation, Bluetooth is always in the broadcasting state. During low power consumption, it broadcasts every 0.5 seconds, once every 0.1 seconds, and the rest of the time is in a sleep state. When connected to Bluetooth, the power consumption of the two working modes is similar (of course,
   the low power consumption will be a little lower),If it is not particularly sensitive to power consumption or it will be in a disconnected state for a long time after power-on, it is better to keep the module in a normal working state.
6. The following table is the current under each working state, which is measured in the experimental environment, and the results are for reference only.

	Serial number	Current	Description
AT+CL00\r\n   Low power working mode	Boot moment	12mA	When the chip is powered on, the peripherals need to be initialized. The instantaneous current is relatively large, and this time is maintained for 300ms, and it enters a low-power state.
	Working Status – Not Connected	1mA, 5mA alternately	The chip is in normal working state, broadcasts normally, and is in a periodic state of sleep, wake-up broadcast, and sleep. The purpose is to save power consumption, the cycle is 500ms. 100ms broadcast once, 400ms sleep
	Working status – to connect	6mA	When the connection is successful, the chip will no longer go to sleep. but at work
AT+CL01\r\n   normal working mode	Boot moment	25mA	When the chip is powered on, the peripherals need to be initialized. The instantaneous current is relatively large, this time is maintained for 300ms, and it enters the 5mA working state
	Whether connected or not	6.5mA	The chip is always working. Small fluctuations in current, negligible

If you feel that the above power consumption is relatively high, you can use 3.3V to directly supply power to the module and the current will further

decrease

Chip BLE enable and SPP enables

AT+B401\r\n	Enable BLE function. Of course AT+B400\r\n is closed
AT+B500\r\n	Disable the function of SPP. Of course AT+B501\r\n is turned on
AT+T4\r\n	Check whether the BLE function is enabled. The chip will return T4+01 or T4+00
AT+T5\r\n	Check whether the SPP function is enabled. The chip will return T5+01 or T5+00

1. After the BLE/SPP function is turned off, it must be powered on again for this function to take effect. Of course it’s the same
2. You only need to set it once, the chip automatically saves the parameters, and you don’t need to set it next time
3. After the BLE/SPP function is turned off, the mobile phone cannot search for the name of BLE.

Description of the error message returned by the chip

ER+1\r\n	The received data frame is incorrect
ER+2\r\n	The received command does not exist, that is, the string like AT+KK you sent cannot be

	found
ER+3\r\n	The received AT command did not receive a carriage return and line feed, that is, \r\n
ER+4\r\n	The parameter sent by the command is out of range, or the command format is incorrect. Please check your AT commands
ER+7\r\n	The MCU sends data to the mobile phone, but the mobile phone does not open notify. In the successful state of BLE connection

Focus on the description of notify [monitoring]. After the test APP on the mobile phone is connected to the Bluetooth chip, notify must be turned on. The bluetooth chip can
send data to the mobile phone. When the mobile phone sends data to the Bluetooth chip,it is enough to use the write feature.

Chip power-on callback information settings

AT+CR00\r\n	Turn off postback messages for power-on. Be careful to restart the power after setting
AT+CR01\r\n	Enable the return message of chip power-on. It is valid at the next power-on. Be careful to restart the power after setting

Note: After this function is turned off, it will also turn off the OK or ER+X return information that is actively returned after the AT command is executed. It is recommended to keep it turned on here.

Transparent transmission description

1. After the Bluetooth connection, the module automatically enters the transparent transmission mode. Except for the completely correct AT command, the rest of the data will be transparently transmitted.
2. The maximum amount of data that can be handled in a single time is 1024 bytes. SPP recommends that it should not exceed 512 bytes at a time.
3. The MTU (maximum communication packet length) of the mobile phone APP generally defaults to 20 bytes for 1 data packet; when the data packet sent by the module exceeds 20 bytes, the module will automatically divide the packet according to the set MTU; you can Modify the MTU to modify the data interaction speed (the larger the
   MTU, the faster the data interaction speed).

Documents / Resources

WAVESHARE ELECTRONICS Pico-BLE Dual-Mode Bluetooth-compatible 5.1 Expansion Module [pdf] User Manual Pico-BLE, Dual-Mode Bluetooth-compatible 5.1 Expansion Module

References

• User Manual