Schedule Message Example

This example demonstrates how to schedule messages for satellite transmission. The SendMessage job will schedule MESSAGES_PER_DAY messages per day. The FLEX_MessageSchedule function pushes each message to the queue. The return value of FLEX_MessageSchedule indicates the load of the queue. A return value greater than one indicates that the queue is overloaded and that messages may begin to be dropped. The message will be transmitted when a satellite is overhead and the satellite passes can be checked from Access Times in Device Manager.

 
#include <stdio.h>
#include "flex.h"
 
#define APPLICATION_NAME "Schedule Message Example"
 
// Note: Modify this according to the application requirements.
#define MESSAGES_PER_DAY 4
 
typedef struct {
  uint16_t sequence_number;
  uint32_t time;
  // ADD YOUR PARAMETERS HERE
} __attribute__((packed)) message;
 
static time_t SendMessage(void) {
  static uint16_t sequence_number = 0;
  message message;
 
  message.sequence_number = sequence_number++;
  message.time = FLEX_TimeGet();
  // POPULATE YOUR DATA HERE
 
  // Schedule messages for satellite transmission
  FLEX_MessageSchedule((void *)&message, sizeof(message));
  printf("Scheduled message: %u %lu\n", message.sequence_number, message.time);
 
  return (FLEX_TimeGet() + 24 * 3600 / MESSAGES_PER_DAY);
}
 
void FLEX_AppInit() {
  printf("%s\n", APPLICATION_NAME);
  FLEX_JobSchedule(SendMessage, FLEX_ASAP());
}