Parameter question for limiting the number of publish timer operations in the Teensy 4.1 board

[ChoiYouJung]

Issue template

• Hardware description: Teensy4.1

• RTOS: No

• Installation type: Arduino IDE

• Version or commit hash: humble

Steps to reproduce the issue

(1) Code Behavior Description

• Creating 5 publishers and 5 timers on 1 node to publish ros message
• The code is written based on the examples in micro_ros_arduino/examples/micro-ros_publisher.
• micro_ros_arduino/examples/micro-ros_publisher Keep the contents of the example code and add the following code.

#include <micro_ros_arduino.h>

#include <stdio.h>
#include <rcl/rcl.h>
#include <rcl/error_handling.h>
#include <rclc/rclc.h>
#include <rclc/executor.h>

#include <std_msgs/msg/int32.h>

rcl_publisher_t publisher;
std_msgs__msg__Int32 msg;
rclc_executor_t executor;
rclc_support_t support;
rcl_allocator_t allocator;
rcl_node_t node;
rcl_timer_t timer;

rcl_publisher_t publisher2; // new
rcl_publisher_t publisher3; // new
rcl_publisher_t publisher4; // new
rcl_publisher_t publisher5; // new

std_msgs__msg__Int32 msg2; // new
std_msgs__msg__Int32 msg3; // new
std_msgs__msg__Int32 msg4; // new
std_msgs__msg__Int32 msg5; // new

rcl_timer_t timer2; // new
rcl_timer_t timer3; // new
rcl_timer_t timer4; // new
rcl_timer_t timer5; // new

#define LED_PIN 13

#define RCCHECK(fn) { rcl_ret_t temp_rc = fn; if((temp_rc != RCL_RET_OK)){error_loop();}}
#define RCSOFTCHECK(fn) { rcl_ret_t temp_rc = fn; if((temp_rc != RCL_RET_OK)){}}


void error_loop(){
  while(1){
    digitalWrite(LED_PIN, !digitalRead(LED_PIN));
    delay(100);
  }
}

void timer_callback(rcl_timer_t * timer, int64_t last_call_time)
{  
  RCLC_UNUSED(last_call_time);
  if (timer != NULL) {
    RCSOFTCHECK(rcl_publish(&publisher, &msg, NULL));
    msg.data++;
  }
}

 // new
void timer_callback2(rcl_timer_t * timer, int64_t last_call_time)
{  
  RCLC_UNUSED(last_call_time);
  if (timer != NULL) {
    RCSOFTCHECK(rcl_publish(&publisher2, &msg2, NULL));
    msg2.data++;
  }
}

 // new
void timer_callback3(rcl_timer_t * timer, int64_t last_call_time)
{  
  RCLC_UNUSED(last_call_time);
  if (timer != NULL) {
    RCSOFTCHECK(rcl_publish(&publisher3, &msg3, NULL));
    msg3.data++;
  }
}

 // new
void timer_callback4(rcl_timer_t * timer, int64_t last_call_time)
{  
  RCLC_UNUSED(last_call_time);
  if (timer != NULL) {
    RCSOFTCHECK(rcl_publish(&publisher4, &msg4, NULL));
    msg4.data++;
  }
}

 // new
void timer_callback5(rcl_timer_t * timer, int64_t last_call_time)
{  
  RCLC_UNUSED(last_call_time);
  if (timer != NULL) {
    RCSOFTCHECK(rcl_publish(&publisher5, &msg5, NULL));
    msg5.data++;
  }
}

void setup() {
  set_microros_transports();
  
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, HIGH);  
  
  delay(2000);

  allocator = rcl_get_default_allocator();

  //create init_options
  RCCHECK(rclc_support_init(&support, 0, NULL, &allocator));

  // create node
  RCCHECK(rclc_node_init_default(&node, "micro_ros_arduino_node", "", &support));

  // create publisher
  RCCHECK(rclc_publisher_init_default(
    &publisher,
    &node,
    ROSIDL_GET_MSG_TYPE_SUPPORT(std_msgs, msg, Int32),
    "micro_ros_arduino_node_publisher"));

 // new
RCCHECK(rclc_publisher_init_default(
    	&publisher2,
    	&node,
    	ROSIDL_GET_MSG_TYPE_SUPPORT(std_msgs, msg, Int32),
    	"publisher2"));

 // new
RCCHECK(rclc_publisher_init_default(
    	&publisher3,
    	&node,
    	ROSIDL_GET_MSG_TYPE_SUPPORT(std_msgs, msg, Int32),
    	"publisher3"));

 // new
RCCHECK(rclc_publisher_init_default(
    	&publisher4,
    	&node,
    	ROSIDL_GET_MSG_TYPE_SUPPORT(std_msgs, msg, Int32),
    	"publisher4"));

 // new
RCCHECK(rclc_publisher_init_default(
    	&publisher5,
    	&node,
    	ROSIDL_GET_MSG_TYPE_SUPPORT(std_msgs, msg, Int32),
    	"publisher5"));

  // create timer,
  const unsigned int timer_timeout = 1000;

 const unsigned int timer_timeout2 = 1000;  // new
 const unsigned int timer_timeout3 = 1000;  // new
 const unsigned int timer_timeout4 = 1000;  // new
 const unsigned int timer_timeout5 = 1000;  // new

  RCCHECK(rclc_timer_init_default(
    &timer,
    &support,
    RCL_MS_TO_NS(timer_timeout),
    timer_callback));

// new
 RCCHECK(rclc_timer_init_default(
    	&timer2,
    	&support,
    	RCL_MS_TO_NS(timer_timeout),
    	timer_callback2));

// new
 RCCHECK(rclc_timer_init_default(
    	&timer3,
    	&support,
    	RCL_MS_TO_NS(timer_timeout),
    	timer_callback3));

// new
 RCCHECK(rclc_timer_init_default(
    	&timer4,
    	&support,
    	RCL_MS_TO_NS(timer_timeout),
    	timer_callback4));

// new
 RCCHECK(rclc_timer_init_default(
    	&timer5,
    	&support,
    	RCL_MS_TO_NS(timer_timeout),
    	timer_callback5));


  // create executor
  RCCHECK(rclc_executor_init(&executor, &support.context, 5, &allocator)); // new
  RCCHECK(rclc_executor_add_timer(&executor, &timer)); // new
  RCCHECK(rclc_executor_add_timer(&executor, &timer2)); // new
  RCCHECK(rclc_executor_add_timer(&executor, &timer3)); // new
  RCCHECK(rclc_executor_add_timer(&executor, &timer4)); // new
  RCCHECK(rclc_executor_add_timer(&executor, &timer5)); // new

  msg.data = 0;
  msg2.data = 0;  // new
  msg3.data = 0;  // new
  msg4.data = 0;  // new
  msg5.data = 0;  // new

}

void loop() {
  delay(100);
  RCSOFTCHECK(rclc_executor_spin_some(&executor, RCL_MS_TO_NS(100)));
}

Expected behavior

• 5 timers publish 5 ROS messages alternately every 1 second.

Actual behavior

• Through the Micro-ROS Agent log, it was confirmed that 5 publishers were created.
• The message is not published, and the error_loop() function is entered, and the LED is turned on/off periodically.

Additional information

• The operating system of the Arduino IDE is Windows 10.
• Question: Is there a parameter inside Micro-ROS to set the Timer to operate normally?

[pablogs9]

In which line is error_loop triggered?

[ChoiYouJung]

In which line is error_loop triggered?

It happens in the following code.

// new
RCCHECK(rclc_timer_init_default(
&timer5,
&support,
RCL_MS_TO_NS(timer_timeout),
timer_callback5));

[pablogs9]

Add a line here:

micro_ros_arduino/extras/library_generation/colcon.meta

Line 41 in 80d4330

"rmw_microxrcedds": {

Configuring the available number of condition variables https://github.com/micro-ROS/rmw_microxrcedds/blob/bc4eb312ac4601a4137c35f4a56b9b83b4b18339/rmw_microxrcedds_c/CMakeLists.txt#L57 to 5

And rebuild the library: https://github.com/micro-ROS/micro_ros_arduino#how-to-build-the-precompiled-library

[ChoiYouJung]

oh!!

As I answered, when I changed the parameter to 5 and tried to operate it, it works normally.

thank you for helping me.

In addition, I have a question about that parameter.

As a result of checking at the address below, what does ROS guard conditions mean in the description of the corresponding parameter? Or is there something else that parameter affects besides the Timer?

https://docs.vulcanexus.org/en/latest/rst/tutorials/micro/memory_management/memory_management.html?highlight=RMW_UXRCE_MAX_GUARD_CONDITION#entity-creation

RMW_UXRCE_MAX_GUARD_CONDITION : Maximum number of micro-ROS guard conditions (used for timers among other things). Default value: 4.

[pablogs9]

Just that internally the timers probably uses a guard condition. This is why with the default compilation you only can use 4.

[pablogs9]

Closing as resolved