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The Dragonwing IQ8-EVK contains one low-speed connector (JLS1) that provides access to various GPIOs, CAN, QUPs, and other interfaces.

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Pinout

The figure below shows the default functions of the IQ-8275 EVK 40-pin LS connector.

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GPIOs

The following commands require root privileges. Use sudo su to switch to the root user.

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Identify GPIO Subsystem Numbers

Identify the base GPIO number by running the following command and looking for platform/f000000.pinctrl (gpiochip4). For IQ-8275, the base is 560.
Example: For LS connector Pin 5, GPIO number is 54. The GPIO subsystem number is: 560 + 54 = 614.

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Control GPIOs via sysfs

1

Export the GPIO

2

Configure direction and value

3

Unexport when done

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GPIO Code Examples

Sets pin 5 as output, pin 7 as input, and loops to check the level of pin 7.
1

Compile

2

Connect pins and run

Short pin 5 and pin 7 with a Dupont wire.
Pay attention to pin order. Do not short power and ground pins — this may damage the board.

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UART

Pins 5 and 7 are configured for UART by default (GPIO lines 54 and 55, mapping to uart12 = qup1_se5 (0xa98000)). Follow the Modify serial engine node procedure to enable the UART interface. After enabling, the device node appears at /dev/ttyHS3.
1

Connect pins

Short pin 5 and pin 7 with a Dupont wire.
Do not short power and ground pins.
2

Configure UART

3

Open two SSH terminals

Terminal 1 (RX): sudo cat /dev/ttyHS3Terminal 2 (TX): echo "hello world!" > /dev/ttyHS3

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I2C

Pins 8 and 10 are configured for I2C by default (GPIO lines 32 and 33, mapping to i2c4 = qup0_se4 (0x990000)). Follow the Modify serial engine node procedure to enable the I2C interface.

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SPI

Pins 11 and 13 are configured for SPI by default (GPIO lines 44 and 45, mapping to spi10 = qup1_se3 (0xa8c000)). Follow the Modify serial engine node procedure to enable the SPI interface.