isolating sections of string

Programming Questions

voila1

in Programming Questions • 10 months ago

When i read from the serial port i get the response in the format "Read 00 00 00 " (this is because of the usb/serial conversion tool i am using) where i need actual returned values (in this case 00 00 00) i have been using the substring command coupled with the length of the returned string and some maths to do this.

readTarget();               //see what it returns
       String ssdata1 = myString.substring(L1 - 6);      // take the last 6 bytes to clear all the response text from the usbio ie "spi read" etc
       data11=int(ssdata1);

where readTarget() is the serial read and L1 is the length of the read string such as below

void readTarget(){
csn(01);                                                //chip enable/select config subroutine
   myPort.write("SPITX 00\n");
   countdelay(5);
   myPort.readBytes(byteBuffer); //get bytes of data
       myString = new String (byteBuffer); //get values and put them into a string
       L1 = myString.length();                 //work out length of response
csn(05);
}

the question is: is there a better/more reliable way of doing the same thing?

also my formatting doesnt seem to be correct as i never get consistant strings (if you have any ideas on how to solve i would be most interested) ie:

0
RTPRT 5
Read 00 00 0
0
Read

WRTPRT 5
Rea
0
RTPRT 5
Read 000 00
0
5
Read 00 00 00

W
0
T 5
Read 00 00 00

0
SPI Read

WRTPRT 5

Replies(4)

PhiLho

Re: isolating sections of string

10 months ago

I would use split() with the space token, seems simpler and more reliable.

voila1

Re: isolating sections of string

10 months ago

Surely then i would have to use the reverse() function, select array[0] to get the numerical values, then convert back into a regular string, then into an integer in order for the gwoptics graphing library to plot it, (as you can't seem to go from string[] to int?)

which would be longer/more complicated than my current code

PhiLho

Re: isolating sections of string

10 months ago

I just don't understand you reasoning, sorry. Or your need.
If you need to just ditch the prefix, using indexOf(" ") to find the position of the first space, then substring() from there.

voila1

Re: isolating sections of string

10 months ago

sorry for not explaining my point better. I guess it helps if i start from the beginning?

I am (trying) to directly control an radio receiver module ( http://radio-hobby.org/uploads/datasheets/rfm/rfm70.pdf) through the pc (using processing). As the rf module has an spi interface i am using a usb/serial device (which i shall just call "device"from now on. The issue with using this device is that the data to be written to the RF module has to be in the format "SPITX <data>" and the device returns "SPI read <data>".

the code i was trying to explain was something like this.

myPort.readBytes(byteBuffer); //get bytes of data
myString = new String (byteBuffer); //get values and put them into a string
String[] datastring = split(myString, ' '); //split the strings when there is a space
reverse(datastring); //arrange the array into the format "<data>, read, SPI"
int datastringint = int(datastring[0]); //convert array location 0 (<data>) into an int
data11=datastringint; //store data somewhere else

does this help?

I should say that the write routine i am using is fine i am just trying to make sure i get <data> but nothing else