uart stuck reading 8000bits/s

Projects Networking, Protocols, and Devices
1

Hello,

I am trying to read data from UART and display but only first byte is read: 100 packet / second = 8000bits/s

No problem, 1 packet / second rate.
I tried baudrate 9600 and 115200.

Any idea?

Thank you.

2

Any idea?

You posted no code. You did not explain what is sending the data. You did not explain how you know the Arduino is "stuck".

So, no, I have no idea how to help you.

3

Sorry, PaulS

My code:

#define SERIAL_BUFFER_SIZE 16
#define SIGNIFICANT_FIGURES 10
#define SERIAL_BAUDRATE 115200
#define SAMPLE_SIZE 15000

void print_results() {}
int real_time_mean() {}

char buffer_serial[16];
byte ds_i = 0;
unsigned int total_samples = 0;

void setup() {
Serial.begin(SERIAL_BAUDRATE);
while(!Serial) {}
Serial.print("Sample size: ");
Serial.println(SAMPLE_SIZE);
delay(5000);
Serial.flush();
}

void loop() {
if (total_samples < SAMPLE_SIZE - 1) {
//
}
else {
total_samples = 0;
// print_results();
}

if (Serial.available() > 0 ) {
buffer_serial[ds_i++] = (char) Serial.read();

if (buffer_serial[ds_i - 1] == '\n') {
total_samples = total_samples + 1;
Serial.print("Sample ");
Serial.print(total_samples);
Serial.print(": ");
Serial.println(atof(buffer_serial));

// err = real_time_mean();

ds_i = 0;
}
}

}
}

RESULTS

Sending data ~ 100bits/s: OK

Sample size: 15000

Sample 1: 1551599.00
Sample 2: 1390301.00
Sample 3: 1217744.00
Sample 4: 1054522.00
Sample 5: 910601.00

Sample 6: 795179.00
.....

Sending data ~ 800bits/s: NOK

Sample size: 15000

Sample 1: 0.00
Sample 2:
-215647.00
Sample 3: -2416445.00
Sample 4: -3
454754.00
Sample 5: -2502710.00
Sample 6: -183
856.00
Sample 7: 21030.00
Sample 8: 0.00
Samp
le 9: 0.00
Sample 10: 0.00
....
Sample 500: 0.00

4

To make it easy for people to help you please modify your post and use the code button </>

so your code looks like this

and is easy to copy to a text editor. See How to use the Forum

In the meantime have a look at the examples in Serial Input Basics - simple reliable ways to receive data.

By the way, the baud rate determines the number of bits per second.

...R

5

That code does not compile;; it has a } too many (or is missing a {), your call.

You have not added a terminating nul character to your buffer. After Arduino reset, the buffer is filled with zeroes and you will have a nul-terminated character array. After you have received the data and printed it, you reset ds_i but do not clear the buffer.

      ds_i = 0;
      // add the below to clear the buffer
      memset(buffer_serial, 0, sizeof(buffer_serial));

Or nul-terminate the received data before converting

    if (buffer_serial[ds_i - 1] == '\n') {
      // nul-terminate by replacing '\n' by '\0'
      buffer_serial[ds_i - 1] = '\0';
      ...
      ...
}

It might not be the cause of the problem though.