Multiple Nodes

Hi, is there any example or support for multiple nodes?

I have 2 FreeRTOS tasks, each of them is hosting 1 node. Both FreeRTOS tasks are using the same U(S)ART DMA (ie: usart4).

However, when I run the micro_ros_agent on the workstation, it only detects 1 node with the following behavior :
- Both nodes are correctly set up and fully functional when only 1 node is being run.
- The FreeRTOS task that has the higher priority tend to be detected by the micro_ros_agent.
- When hosting both 2 nodes in 1 FreeRTOS task, the first mentioned node tend to be detected by the micro_ros_agent.

Below is the "colcon.meta" which I have set the "-DRMW_UXRCE_MAX_NODES" to 2.

```
{
"names": {
"tracetools": {
"cmake-args": [
"-DTRACETOOLS_DISABLED=ON",
"-DTRACETOOLS_STATUS_CHECKING_TOOL=OFF"
]
},
"rosidl_typesupport": {
"cmake-args": [
"-DROSIDL_TYPESUPPORT_SINGLE_TYPESUPPORT=ON"
]
},
"rcl": {
"cmake-args": [
"-DBUILD_TESTING=OFF",
"-DRCL_COMMAND_LINE_ENABLED=OFF",
"-DRCL_LOGGING_ENABLED=OFF"
]
},
"rcutils": {
"cmake-args": [
"-DENABLE_TESTING=OFF",
"-DRCUTILS_NO_FILESYSTEM=ON",
"-DRCUTILS_NO_THREAD_SUPPORT=ON",
"-DRCUTILS_NO_64_ATOMIC=ON",
"-DRCUTILS_AVOID_DYNAMIC_ALLOCATION=ON"
]
},
"microxrcedds_client": {
"cmake-args": [
"-DUCLIENT_PIC=OFF",
"-DUCLIENT_PROFILE_UDP=OFF",
"-DUCLIENT_PROFILE_TCP=OFF",
"-DUCLIENT_PROFILE_DISCOVERY=OFF",
"-DUCLIENT_PROFILE_SERIAL=OFF",
"-UCLIENT_PROFILE_STREAM_FRAMING=ON",
"-DUCLIENT_PROFILE_CUSTOM_TRANSPORT=ON"
]
},
"rmw_microxrcedds": {
"cmake-args": [
"-DRMW_UXRCE_MAX_NODES=2",
"-DRMW_UXRCE_MAX_PUBLISHERS=10",
"-DRMW_UXRCE_MAX_SUBSCRIPTIONS=5",
"-DRMW_UXRCE_MAX_SERVICES=1",
"-DRMW_UXRCE_MAX_CLIENTS=1",
"-DRMW_UXRCE_MAX_HISTORY=4",
"-DRMW_UXRCE_TRANSPORT=custom"
]
}
}
}
```

Can someone please guide me on this?

Start with the issue's colcon.meta configuration, especially RMW_UXRCE_MAX_NODES and the custom transport settings, then compare the one-task and two-task FreeRTOS cases using the micro_ros_agent. Check how the shared USART4 DMA is used by both tasks and whether the two-node setup can be reproduced. Done means documenting the supported configuration or identifying the cause of only one node being detected.

Written by the indexing model from the issue text.