Hardware requirements
Type-C USB cable
FRDM-MCXW71 Board
Personal Computer
Board settings
If ENABLE_LOOPBACK is not defined, the example requires 2 sets of boards, each of them is mounted with the base board. To make example work, connections needed to be as follows on each base board:
Board to board connections needed to be as follows:
Node A connect to Node B
Pin Name Board Location Pin Name Board Location
CANH J21-1 CANH J21-1
CANL J21-2 CANL J21-2
GND J21-4 GND J21-4
Prepare the Demo
Connect the micro and mini USB cable between the PC host and the USB ports on the board.
Open a serial terminal on PC for the serial device with these settings:
115200 baud rate
8 data bits
No parity
One stop bit
No flow control
Download the program to the target board.
Either press the reset button on your board or launch the debugger in your IDE to begin running the demo.
Running the demo
When setting ENABLE_LOOPBACK macro and the example runs successfully, you can see the similar information from the terminal as below.
FlexCAN Enhanced Rx FIFO interrupt example.
Loopback mode, Message buffer 0 used for Tx, Enhanced Rx FIFO used for Rx.
Press any key to trigger 4 transmission.
Send Msg0 to Enhanced Rx FIFO: word0 = 0x0, word1 = 0x55, id = 0x123.
Send Msg1 to Enhanced Rx FIFO: word0 = 0x1, word1 = 0x55, id = 0x124.
Send Msg2 to Enhanced Rx FIFO: word0 = 0x2, word1 = 0x55, id = 0x125.
Send Msg3 to Enhanced Rx FIFO: word0 = 0x3, word1 = 0x55, id = 0x126.
Receive Msg0 from Enhanced Rx FIFO: word0 = 0x0, word1 = 0x55, ID Filter Hit: 0, Time stamp: 41410.
Receive Msg1 from Enhanced Rx FIFO: word0 = 0x1, word1 = 0x55, ID Filter Hit: 1, Time stamp: 48882.
Receive Msg2 from Enhanced Rx FIFO: word0 = 0x2, word1 = 0x55, ID Filter Hit: 2, Time stamp: 56352.
Receive Msg3 from Enhanced Rx FIFO: word0 = 0x3, word1 = 0x55, ID Filter Hit: 3, Time stamp: 63821.
Press any key to trigger 4 transmission.
...
2 boards are required to be connected through CAN bus if ENABLE_LOOPBACK is not defined. One board must be chosen as node A and the other board as node B. (Note: Node B should start first) Data is sent continuously between the node A and the node B.
This message displays on the node A terminal:
FlexCAN Enhanced Rx FIFO interrupt example.
Board to board mode.
Node B Enhanced Rx FIFO used for Rx.
Node A Message buffer 0 used for Tx.
Please select local node as A or B:
Note: Node B should start first.
Node:a
Press any key to trigger 4 transmission.
Send Msg0 to Enhanced Rx FIFO: word0 = 0x0, word1 = 0x55, id = 0x123.
Send Msg1 to Enhanced Rx FIFO: word0 = 0x1, word1 = 0x55, id = 0x124.
Send Msg2 to Enhanced Rx FIFO: word0 = 0x2, word1 = 0x55, id = 0x125.
Send Msg3 to Enhanced Rx FIFO: word0 = 0x3, word1 = 0x55, id = 0x126.
Press any key to trigger 4 transmission.
....
This message displays on the node B terminal:
FlexCAN Enhanced Rx FIFO interrupt example.
Board to board mode.
Node B Enhanced Rx FIFO used for Rx.
Node A Message buffer 0 used for Tx.
Please select local node as A or B:
Note: Node B should start first.
Node:b
Start to Wait data from Node A.
Receive Msg0 from Enhanced Rx FIFO: word0 = 0x0, word1 = 0x55, ID Filter Hit: 0, Time stamp: 24286.
Receive Msg1 from Enhanced Rx FIFO: word0 = 0x1, word1 = 0x55, ID Filter Hit: 1, Time stamp: 25059.
Receive Msg2 from Enhanced Rx FIFO: word0 = 0x2, word1 = 0x55, ID Filter Hit: 2, Time stamp: 25745.
Receive Msg3 from Enhanced Rx FIFO: word0 = 0x3, word1 = 0x55, ID Filter Hit: 3, Time stamp: 26431.
Wait for the next 4 messages!
....