Hardware

The following commands allow you to interact with the low level HW on the Bluefruit LE module, such as reading or toggling the GPIO pins, performing an ADC conversion ,etc.:

AT+BAUDRATE

Changes the baud rate used by the HW UART peripheral on the nRF51822.

Codebase Revision: 0.7.0

Parameters: Baud rate, which must be one of the following values:

  • 1200
  • 2400
  • 4800
  • 9600
  • 14400
  • 19200
  • 28800
  • 38400
  • 57600
  • 76800
  • 115200
  • 230400
  • 250000
  • 460800
  • 921600
  • 1000000

Output: The current baud rate

# Set the baud rate to 115200
AT+BAUDRATE=115200
OK

# Check the current baud rate
AT+BAUDRATE
115200
OK

AT+HWADC

Performs an ADC conversion on the specified ADC pin

Codebase Revision: 0.3.0

Parameters: The ADC channel (0..7)

Output: The results of the ADC conversion

AT+HWADC=0
178
OK

AT+HWGETDIETEMP

Gets the temperature in degree celcius of the BLE module's die.  This can be used for debug purposes (higher die temperature generally means higher current consumption), but does not corresponds to ambient temperature and can nto be used as a replacement for a normal temperature sensor.

Codebase Revision: 0.3.0

Parameters: None

Output: The die temperature in degrees celcius

AT+HWGETDIETEMP
32.25
OK

AT+HWGPIO

Gets or sets the value of the specified GPIO pin (depending on the pin's mode).

Codebase Revision: 0.3.0

Parameters: The parameters for this command change depending on the pin mode.

OUTPUT MODE: The following comma-separated parameters can be used when updating a pin that is set as an output:

  • Pin numbers
  • Pin state, where:
    • 0 = clear the pin (logic low/GND)
    • 1 = set the pin (logic high/VCC)

INPUT MODE: To read the current state of an input pin or a pin that has been configured as an output, enter the pin number as a single parameter.

Output: The pin state if you are reading an input or checking the state of an input pin (meaning only 1 parameter is supplied, the pin number), where:

  • 0 means the pin is logic low/GND
  • 1 means the pin is logic high/VCC
Trying to set the value of a pin that has not been configured as an output will produce an 'ERROR' response.
Some pins are reserved for specific functions on Bluefruit modules and can not be used as GPIO. If you try to make use of a reserved pin number an 'ERROR' response will be generated.
# Set pin 14 HIGH
AT+HWGPIO=14,1
OK
  
# Set pin 14 LOW
AT+HWGPIO=14,0
OK
  
# Read the current state of pin 14
AT+HWGPIO=14
0
OK
  
# Try to update a pin that is not set as an output
AT+HWGPIOMODE=14,0
OK
AT+HWGPIO=14,1
ERROR

AT+HWGPIOMODE

This will set the mode for the specified GPIO pin (input, output, etc.).

Codebase Revision: 0.3.0

Parameters: This command one or two values (comma-separated in the case of two parameters being used):

  • The pin number
  • The new GPIO mode, where:
    • 0 = Input
    • 1 = Output
    • 2 = Input with pullup enabled
    • 3 = Input with pulldown enabled

Output: If a single parameters is passed (the GPIO pin number) the current pin mode will be returned.

Some pins are reserved for specific functions on Bluefruit modules and can not be used as GPIO. If you try to make use of a reserved pin number an 'ERROR' response will be generated.
# Configure pin 14 as an output
AT+HWGPIOMODE=14,0
OK

# Get the current mode for pin 14
AT+HWPGIOMODE=14
0
OK

AT+HWI2CSCAN

Scans the I2C bus to try to detect any connected I2C devices, and returns the address of devices that were found during the scan process.

Codebase Revision: 0.3.0

Parameters: None

Output: A comma-separated list of any I2C address that were found while scanning the valid address range on the I2C bus, or nothing is no devices were found.

# I2C scan with two devices detected
AT+HWI2CSCAN
0x23,0x35
OK

# I2C scan with no devices detected
AT+HWI2CSCAN
OK

AT+HWVBAT

Returns the main power supply voltage level in millivolts

Codebase Revision: 0.3.0

Parameters: None

Output: The VBAT level in millivolts

AT+HWVBAT
3248
OK

AT+HWRANDOM

Generates a random 32-bit number using the HW random number generator on the nRF51822 (based on white noise).

Codebase Revision: 0.4.7

Parameters: None

Output: A random 32-bit hexadecimal value (ex. '0x12345678')

AT+HWRANDOM
0x769ED823
OK

AT+HWMODELED

Allows you to override the default behaviour of the MODE led (which indicates the operating mode by default).

Codebase Revision: 0.6.6

Parameters: LED operating mode, which can be one of the following values:

  • disable or DISABLE or 0 - Disable the MODE LED entirely to save power
  • mode or MODE or 1 - Default behaviour, indicates the current operating mode
  • hwuart or HWUART or 2 - Toggles the LED on any activity on the HW UART bus (TX or RX)
  • bleuart or BLEUART or 3 - Toggles the LED on any activity on the BLE UART Service (TX or RX characteristic)
  • spi or SPI or 4 - Toggles the LED on any SPI activity
  • manual or MANUAL or 5 - Manually sets the state of the MODE LED via a second comma-separated parameter, which can be onoff, or toggle.

Output: If run with no parameters, returns an upper-case string representing the current MODE LED operating mode from the fields above

# Get the curent MODE LED setting
AT+HWMODELED
MODE
OK
  
# Change the MODE LED to indicate BLE UART activity
AT+HWMODELED=BLEUART
OK

# Manually toggle the MODE LED
AT+HWMODELED=MANUAL,TOGGLE
OK

AT+UARTFLOW

Enables or disable hardware flow control (CTS + RTS) on the UART peripheral block of the nRF51822.

Codebase Revision: 0.7.0

Parameters: HW flow control state, which can be one of:

  • on
  • off
  • 0
  • 1

Output: If run with no parameters, returns a number representing whether flow control is enabled (1) or disabled (0).

# Check the current flow control state
AT+UARTFLOW
1
OK

# Disable HW flow control
AT+UARTFLOW=off
OK
Last updated on 2016-06-23 at 01.47.12 PM Published on 2015-08-07 at 06.02.52 PM