Introduction to Beaglebone Black

The Beaglebone Black is a low-cost, community-supported development platform for developers and hobbyists. This credit-card-sized Linux computer is produced by Texas Instruments in association with Digi-Key and Newark element14. It is a powerful device that can be used in various applications, from robotics to home automation.

Key Features of Beaglebone Black

• AM335x 1GHz ARM® Cortex-A8 processor
• 512MB DDR3 RAM
• 4GB 8-bit eMMC on-board flash storage
• 3D graphics accelerator
• NEON floating-point accelerator
• 2x PRU 32-bit microcontrollers
• USB client for power & communications
• USB host
• Ethernet
• HDMI
• 2x 46 pin headers

Beaglebone Black Pinout

The Beaglebone Black has two 46-pin headers, P8 and P9, that provide access to the various interfaces and peripherals of the board. These headers allow users to connect various sensors, actuators, and other devices to the board.

P8 Header Pinout

Pin	Function	Pin	Function
1	GND	2	GND
3	GPIO1_6	4	GPIO1_7
5	GPIO1_2	6	GPIO1_3
7	TIMER4	8	TIMER7
9	TIMER5	10	TIMER6
11	GPIO1_13	12	GPIO1_12
13	EHRPWM2B	14	GPIO0_26
15	GPIO1_15	16	GPIO1_14
17	GPIO0_27	18	GPIO2_1
19	EHRPWM2A	20	GPIO1_31
21	GPIO1_30	22	GPIO1_5
23	GPIO1_4	24	GPIO1_1
25	GPIO1_0	26	GPIO1_29
27	GPIO2_22	28	GPIO2_24
29	GPIO2_23	30	GPIO2_25
31	UART5_CTSN	32	UART5_RTSN
33	UART4_RTSN	34	UART3_RTSN
35	UART4_CTSN	36	UART3_CTSN
37	UART5_TXD	38	UART5_RXD
39	GPIO2_12	40	GPIO2_13
41	GPIO2_10	42	GPIO2_11
43	GPIO2_8	44	GPIO2_9
45	GPIO2_6	46	GPIO2_7

P9 Header Pinout

Pin	Function	Pin	Function
1	GND	2	GND
3	DC_3.3V	4	DC_3.3V
5	VDD_5V	6	VDD_5V
7	SYS_5V	8	SYS_5V
9	PWR_BUT	10	SYS_RESETn
11	UART4_RXD	12	GPIO1_28
13	UART4_TXD	14	EHRPWM1A
15	GPIO1_16	16	EHRPWM1B
17	I2C1_SCL	18	I2C1_SDA
19	I2C2_SCL	20	I2C2_SDA
21	UART2_TXD	22	UART2_RXD
23	GPIO1_17	24	UART1_TXD
25	GPIO3_21	26	UART1_RXD
27	GPIO3_19	28	SPI1_CS0
29	SPI1_D0	30	SPI1_D1
31	SPI1_SCLK	32	VDD_ADC
33	AIN4	34	GNDA_ADC
35	AIN6	36	AIN5
37	AIN2	38	AIN3
39	AIN0	40	AIN1
41	CLKOUT2	42	GPIO0_7
43	GND	44	GND
45	GND	46	GND

Beaglebone Black Pin Configuration

The Beaglebone Black uses a pin multiplexing system, which allows each pin to have multiple functions. The specific function of each pin is determined by the pin multiplexing configuration.

GPIO (General Purpose Input/Output)

GPIO pins can be configured as either inputs or outputs. They are commonly used to interface with various sensors, buttons, LEDs, and other devices.

Example code for configuring a GPIO pin as an output and toggling its state:

import Adafruit_BBIO.GPIO as GPIO
import time

LED_PIN = "P8_7"

GPIO.setup(LED_PIN, GPIO.OUT)

while True:
    GPIO.output(LED_PIN, GPIO.HIGH)
    time.sleep(1)
    GPIO.output(LED_PIN, GPIO.LOW)
    time.sleep(1)

PWM (Pulse Width Modulation)

PWM pins can generate a pulse width modulated signal, which is useful for controlling the brightness of LEDs, the speed of motors, or the position of servos.

Example code for generating a PWM signal:

import Adafruit_BBIO.PWM as PWM

PWM_PIN = "P9_14"
PWM.start(PWM_PIN, 50, 1000)

while True:
    duty_cycle = input("Enter duty cycle (0-100): ")
    PWM.set_duty_cycle(PWM_PIN, float(duty_cycle))

I2C (Inter-Integrated Circuit)

I2C is a serial communication protocol that allows multiple devices to communicate with each other using just two wires: SCL (Serial Clock) and SDA (Serial Data).

Example code for reading data from an I2C device:

import Adafruit_BBIO.I2C as I2C

DEVICE_ADDR = 0x68

i2c = I2C.I2C(2)
i2c.write8(DEVICE_ADDR, 0x00)
data = i2c.readU8(DEVICE_ADDR, 0x01)
print("Data:", data)

SPI (Serial Peripheral Interface)

SPI is another serial communication protocol that uses four wires: SCLK (Serial Clock), MOSI (Master Output Slave Input), MISO (Master Input Slave Output), and CS (Chip Select).

Example code for reading data from an SPI device:

import Adafruit_BBIO.SPI as SPI

spi = SPI.SPI(0, 0)
spi.mode = 0
spi.msh = 1000000
data = spi.xfer2([0x01, 0x02, 0x03])
print("Data:", data)

UART (Universal Asynchronous Receiver-Transmitter)

UART is a serial communication protocol that is commonly used for communication between the Beaglebone Black and other devices, such as GPS modules or Bluetooth modules.

Example code for reading data from a UART device:

import Adafruit_BBIO.UART as UART
import serial

UART.setup("UART1")
ser = serial.Serial(port="/dev/ttyO1", baudrate=9600)
data = ser.read(10)
print("Data:", data)

Beaglebone Black Pin Specifications

The Beaglebone Black’s pins have specific electrical characteristics that must be considered when interfacing with external devices.

Voltage Levels

• GPIO pins: 3.3V
• VDD_5V pins: 5V
• SYS_5V pins: 5V
• DC_3.3V pins: 3.3V
• VDD_ADC pin: 1.8V

Current Limits

• GPIO pins: 4-6mA
• VDD_5V and SYS_5V pins: 250mA (combined)
• DC_3.3V pins: 250mA (combined)

ADC (Analog-to-Digital Converter)

The Beaglebone Black has a 12-bit ADC with 7 channels (AIN0 to AIN6). The ADC has a voltage range of 0-1.8V.

Example code for reading an analog value from an ADC pin:

import Adafruit_BBIO.ADC as ADC
import time

ADC.setup()
ANALOG_PIN = "P9_40"

while True:
    value = ADC.read(ANALOG_PIN) * 1.8
    print("Voltage:", value)
    time.sleep(0.1)

Beaglebone Black Pin Applications

The versatility of the Beaglebone Black’s pins allows for a wide range of applications, from simple projects to complex systems.

Sensor Interfacing

The Beaglebone Black can interface with various sensors using its GPIO, I2C, SPI, and ADC pins. Some common sensors include:

• Temperature sensors (e.g., LM35, DS18B20)
• Humidity sensors (e.g., DHT11, DHT22)
• Pressure sensors (e.g., BMP180, MPL3115A2)
• Accelerometers and gyroscopes (e.g., MPU6050, LSM9DS1)

Motor Control

PWM pins can be used to control the speed and direction of DC motors and servos. The Beaglebone Black can also interface with motor drivers (e.g., L293D, TB6612FNG) to control larger motors.

Display and User Interface

The Beaglebone Black can interface with various displays and user interface components using its GPIO and I2C pins:

• LCD and OLED displays (e.g., SSD1306, ST7735)
• Touchscreens (e.g., TSC2046)
• Buttons and switches
• Rotary encoders

Communication and Networking

The Beaglebone Black’s UART pins can be used to communicate with other devices, such as GPS modules, Bluetooth modules, or other microcontrollers. The board also has built-in Ethernet and USB host capabilities for networking and communication with other devices.

Frequently Asked Questions (FAQ)

1. What is the maximum current that can be drawn from the Beaglebone Black’s GPIO pins?
   The maximum current that can be safely drawn from a single GPIO pin is 4-6mA. If more current is required, an external driver circuit should be used.

2. Can I use the Beaglebone Black’s ADC pins to measure voltages higher than 1.8V?
   No, the ADC pins have a maximum input voltage of 1.8V. To measure higher voltages, you must use a voltage divider circuit to scale the voltage down to the appropriate range.

3. How can I control the brightness of an LED using the Beaglebone Black?
   To control the brightness of an LED, you can use one of the PWM pins. By varying the duty cycle of the PWM signal, you can adjust the brightness of the LED.

4. Can I use the Beaglebone Black to control a 5V device using the GPIO pins?
   No, the GPIO pins operate at 3.3V and cannot directly control 5V devices. To interface with 5V devices, you must use a level shifter or an appropriate driver circuit.

5. How do I communicate with I2C devices using the Beaglebone Black?
   To communicate with I2C devices, you can use the Adafruit_BBIO library in Python. First, set up the I2C bus using the I2C.setup() function, then use the I2C.read() and I2C.write() functions to read from and write to the device.

Conclusion

The Beaglebone Black is a powerful and versatile single-board computer that offers a wide range of possibilities for developers and hobbyists. With its extensive pin headers and various interfaces, the Beaglebone Black can be used in a multitude of applications, from simple projects to complex systems.

By understanding the Beaglebone Black’s pinout, pin configuration, and specifications, users can effectively utilize the board’s capabilities and create innovative projects. The provided code examples and explanations serve as a starting point for working with the different interfaces and peripherals available on the Beaglebone Black.

As the Beaglebone Black community continues to grow, there is an ever-increasing number of resources, libraries, and projects available to help users make the most of this powerful device. Whether you are a beginner or an experienced developer, the Beaglebone Black offers an excellent platform for learning, experimentation, and innovation.