trigger multiple ESP32 via (local) ethernet

[kainer]

Dear Forum,

after getting a little familiar with programming with Arduino, I'm at a point where I can't get any further. I am using an ESP32-POE-ISO. As part of the project, I want to synchronously read several sensors using the I2C protocol. Since several ESP32s are used, I need a method to synchronize them as accurately as possible. For this I use a local NTP server on a Raspberry (connected via Ethernet). Currently I get a jitter of max. +/-100 microseconds. I also tried a UDP broadcast, but the result is similar.
Do any of you have an idea for a method to improve this value (->smaller jitter)? Maybee causing an interrupt via UDP?

Thanks in advance,

Kainer

Code: [Select all] [Expand/Collapse]

1. #include <WiFi.h>
2. #include <ETH.h>
3. #include "time.h"
4.  
5. TaskHandle_t Task1;
6. time_t new_t, old_t;
7. void codeForTask1(void * parameter)
8. {
9.   const long  gmtOffset_sec = 3600;
10.   const int   daylightOffset_sec = 3600;
11. //  time_t new_tl, old_tl;  
12.   for(;;){
13.     delay(1000);
14.     configTime(gmtOffset_sec, daylightOffset_sec, "192.168.1.2");                          
15.   }
16. }
17. void setup()
18. {
19.     Serial.begin(115200);
20.     Serial.println("Start .......");
21.     pinMode(5, OUTPUT);      // set the LED pin mode
22.     ETH.begin();
23.     ETH.config(IPAddress(192, 168, 1, 66),IPAddress(192, 168, 1, 255),IPAddress(255, 255, 255, 0));
24.     delay(100);
25.     xTaskCreatePinnedToCore(codeForTask1,"Task_1",10000,NULL,1,&Task1,0);
26.     old_t=0;
27. }
28.  
29. void loop(){
30.     time(&new_t);
31.     if(difftime(new_t,old_t)!=0)
32.       {
33.         pinMode(5, INPUT);      // set the LED pin mode
34.         delayMicroseconds(100);
35.         old_t=new_t;  
36.       }
37.   pinMode(5, OUTPUT);
38. }
39.  
40.  

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