XLINK

This example application demonstrates the AN01024 application note in FreeRTOS on xcore.ai.

Note

This example application required XTC Tools version 15.2.1 or newer.

Preparing the hardware

This example requires 2 XCORE-AI-EXPLORER boards, and a user provided device to act as an I2C slave.

To setup the board for testing, the following connections must be made:

Table 1 XCORE-AI-EXPLORER to XCORE-AI-EXPLORER Connections 2 Wire

BOARD 0	BOARD 1
GND	GND
X1D65	X1D66
X1D66	X1D65
X1D64	X1D67
X1D67	X1D64
X1D63	X1D68
X1D68	X1D63
X1D62	X1D69
X1D69	X1D62
X1D61	X1D70
X1D70	X1D61

Table 2 XCORE-AI-EXPLORER to XCORE-AI-EXPLORER Connections 5 Wire Additions

BOARD 0	BOARD 1
X1D63	X1D68
X1D68	X1D63
X1D62	X1D69
X1D69	X1D62
X1D61	X1D70
X1D70	X1D61

Table 3 XCORE-AI-EXPLORER Board 0 to Host Connections

BOARD 0	Host
GND	Host GND
SCL	Host SCL
SDA	Host SDA

Building the firmware

Run the following commands in the xcore_iot root folder to build the firmware:

On Linux and Mac:

cmake -B build -DCMAKE_TOOLCHAIN_FILE=xmos_cmake_toolchain/xs3a.cmake
cd build
make example_freertos_xlink_both

On Windows:

cmake -G "NMake Makefiles" -B build -DCMAKE_TOOLCHAIN_FILE=xmos_cmake_toolchain/xs3a.cmake
cd build
nmake example_freertos_xlink_both

Running the firmware

This application requires example_freertos_xlink_0.xe to be run on BOARD 0, IE, the board with a host I2C connection.

Use the following command to determine available device:

xrun --list-devices

From the build folder run:

xrun --id 0 example_freertos_xlink_0.xe

In another console, from the build folder run:

xrun --id 1 example_freertos_xlink_1.xe

BOARD 0 will send out status messages and communication details to slave address 0xC.

The data will contain an ID, followed by a 4 byte payload. The payload is an int32, sent least significant byte first.

Payloads match to ID per the table below:

Table 4 XCORE-AI-EXPLORER to XCORE-AI-EXPLORER Connections 2 Wire

ID	Payload
0x01	RX state
0x82	received data bytes in the last second
0x83	received control tokens in the last second
0x84	timeouts in the last second

Note

Data rates are highly dependant on the electrical characteristics of the physical connection. Refer to xCONNECT Architecture for more information.