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LibrariesinsideFreeRTOS Plus TCP

Updated Jun 2025

Outputting TCP Log Messages via UDP

FreeRTOS-Plus-TCP and FreeRTOS-Plus-FAT Examples

FreeRTOS_debug_printf() and FreeRTOS_printf() are used to output log messages from within the FreeRTOS-Plus-TCP TCP/IP stack, and can be used by the application writer for the same purpose. The UDP logging example demonstrates how to send FreeRTOS_debug_printf() and FreeRTOS_printf() output to a UDP port.

The following settings in FreeRTOSConfig.h configure the UDP logging functionality.

1/* If set to 1 then each message sent via the UDP logging facility will end
2   with rn. If set to 0 then each message sent via the UDP logging facility will
3   end with n. */
4

5 #define configUDP_LOGGING_NEEDS_CR_LF ( 1 )
6 
7/* Sets the maximum length for a string sent via the UDP logging facility. */
8 #define configUDP_LOGGING_STRING_LENGTH ( 200 )
9 
10/* The UDP logging facility buffers messages until the UDP logging task is able
11   to transmit them. configUDP_LOGGING_MAX_MESSAGES_IN_BUFFER sets the maximum
12   number of messages that can be buffered at any one time. */
13 #define configUDP_LOGGING_MAX_MESSAGES_IN_BUFFER ( 20 )
14 
15/* The UDP logging facility creates a task to send buffered messages to the UDP
16   port. configUDP_LOGGING_TASK_STACK_SIZE sets the task's stack size. */
17 #define configUDP_LOGGING_TASK_STACK_SIZE ( 512 )
18 
19/* The UDP logging facility creates a task to send buffered messages to the UDP
20   port. configUDP_LOGGING_TASK_PRIORITY sets the task's priority. It is
21   suggested to give the task a low priority to ensure it does not adversely effect
22   the performance of other TCP/IP stack activity. */
23 #define configUDP_LOGGING_TASK_PRIORITY ( tskIDLE_PRIORITY + 2 )
24   
25 /* The UDP port numbers to use. */
26 #define configUDP_LOGGING_PORT_LOCAL 1499
27 #define configUDP_LOGGING_PORT_REMOTE 1500
28 
29/* The IP address to which the UDP messages are sent.
30   NOTE: If these settings are omitted then the UDP messages will be sent to
31   the local broadcast address, although broadcast messages can be blocked by switches
32   and routers. */
33 #define configUDP_LOGGING_ADDR0 192
34 #define configUDP_LOGGING_ADDR1 168
35 #define configUDP_LOGGING_ADDR2 0
36 #define configUDP_LOGGING_ADDR3 3

Logging messages produced by the free RTOS TCP/IP stack
UDP logging output viewed using UDPTermexternal_link, from Cinetix