Issues receiving serial commands

mike2

A lot of the code I've been finding online for sending and receiving data is using spin code.

I have a c project I'm working on in which I need to send and receive data to a python program over usb.

Here's my code. Does anyone know why it's not working?

#include <stdio.h>
#include <string.h>
#include <propeller.h>
#include <simpletools.h>


int main(void)
{
   // Wait some time
   waitcnt((CLKFREQ+CNT)*5);
   
   char buffer[300];
   int buflen = 300;
   
   serial *term;
   simpleterm_close();
   term = serial_open(31,30,0,57600);
   writeStr(term,"give_data\r");
   getStr(buffer, buflen);   
   waitcnt((CLKFREQ+CNT)*2);
   writeStr(term,"Data received.\r");  


  return 0;
}

Here's my python I run immediately after loading c code into ram using simpleide

import time
import serial


print "Communicating with propeller over COM4"


s = serial.Serial(
    port='COM4',\
    baudrate=57600,\
    parity=serial.PARITY_NONE,\
    stopbits=serial.STOPBITS_ONE,\
    bytesize=serial.EIGHTBITS,\
    timeout=0)


while True:
    data = s.read(9999)
    if len(data) > 0:
        print 'Received:'+ data
        if "give_data" in data:
            print "Sending data to the propeller..."
            s.write("Here is some data\r")
    time.sleep(1)
s.close()

Output

C:\Users\mike\Desktop>python scom.py
Communicating with propeller over COM4
Received:give_data
Sending data to the propeller...
_

kuroneko

FWIW, I can't see how getStr would be connected to term. I'd have used readStr instead.

mike2

Using readstr I get garbled data back...

readStr(term, buffer, buflen); 

C:\Users\mike\Desktop\>python scom.py
Communicating with propeller over COM4
Received:give_data
Sending data to the propeller...
Received:H½ii╢ët°

If I use the parallax serial terminal I can use C read functions like scanf, but I need to get python working.

Same result running this on a linux host

ubuntu@ubuntu:~$ sudo python scom.py
Communicating with propeller over /dev/ttyUSB0
Received:give_data
Sending data to the propeller...
Received:H�ii��t

kuroneko

Just ran the following program, and after I send some response from the terminal I get the Data received message.

#include <stdio.h>
#include <string.h>
#include <propeller.h>
#include <simpletools.h>


int main(void) {
    // Wait some time
    waitcnt(CLKFREQ*3 + CNT);
   
    char buffer[300];
    int buflen = 300;
   
    serial *term;
    simpleterm_close();
    term = serial_open(31, 30, 0, 115200);
    writeStr(term, "give_data\r");
    readStr(term, buffer, buflen);   
    waitcnt(CLKFREQ*2 + CNT);
    writeStr(term, "Data received [");
    writeStr(term, buffer);
    writeStr(term, "]\r");

    return 0;
}

terminal output:

give_data
[COLOR="#FF8C00"]user data from terminal[/COLOR]
Data received [user data from terminal]

Your delays look slightly off but shouldn't have an effect on the transfer as such. You could try a simple loopback first where the prop simply echos the incoming data.

mike2

I changed to use fdserial instead of serial and the problem resolved. I think it might be an issue with python.

#include <stdio.h>
#include <string.h>
#include <propeller.h>
#include <simpletools.h>
#include <simpletext.h>
#include "fdserial.h"


int main(void)
{
   // Wait some time
   pause(3000);
   
   char buffer[300];
   int buflen = 300;
   
   serial *term;
   simpleterm_close();
   term = fdserial_open(31,30,0,57600);
   writeStr(term,"give_data\r");
   readStr(term,buffer, buflen);   
   writeStr(term,"Data received.\r"); 


  return 0;
}

C:\Users\mike\Desktop>python scom.py
Communicating with propeller over COM4
Received:give_data
Sending data to the propeller...
Received:Here is some data
Data received.

kuroneko

Just wondering, as serial is running unbuffered can you increase the number of stopbits on the host side and see if it makes a difference. If it's still too fast at least I'd expect slightly different garbage.

mike2

Your prediction is right on that. If you change the stop bit it changes the garbage that gets spewed back.

[code]
C:\Users\mike\Desktop>python kuronekotest.py
Communicating with propeller over COM4
Received:give_data
Sending data to the propeller...
Received:Hn,