Nuts and Volts - October 2015

sprintf(cmdBuf,”size
microsd%1d.csv\r”,fileNum);
sendStrUart2(cmdBuf);
//wait for card to respond to
//read - about 18mS
i 0;
timeoutms 5000;
do{
 if(CharInQueue2())
 {
 rxBufProg[i++]
 recvchar2();
 }
 tdelayms(1);
  }while(timeoutms— && (rxBufProg
 [i-1]
 ‘>’));
  i 0;
  j 0;
  do{
 if(isspace(rxBufProg[j]))
 {
 ++j;
 }
  }while(isspace(rxBufProg[j]));

■ Screenshot 7. I have set a breakpoint just before the atoi function is called. In the Variables window, you can see how the raw file size information is returned by the OpenLog firmware.

//***********************************************
// MAIN
//***********************************************
int main (void)
{
 BYTE bitein;
init();
 newFile(1);
 listFile();
 writeFile(1);
 readFile(1);
 listFile();
 do{
 bluLED Tog;
 tdelayms(250);
 }while(1);
 
 do{
 sizeBuf[i++] rxBufProg[j++];
 }while(rxBufProg[j-1] 0x0D &&
 rxBufProg[j-1] 0x0A);
 sizeBuf[i-1] 0x00;
 fileSize atoi(sizeBuf);
 return(fileSize);

I had a blast writing this code. I hope you will find it useful. You can get the complete source library via download from the article link. NV

File size is returned as a set of ASCII characters surrounded by carriage return/line feed combinations. Carriage returns and line feeds are considered white space characters. The getFileSize function wades through the white space characters using the isspace function until an ASCII character is encountered. The ASCII characters that make up the file size data are moved to sizeBuf and a null character is appended.

The file size is obtained by performing an ASCII to Integer conversion using the atoi function. In Screenshot 7, I set a breakpoint prior to the atoi function call to capture the raw buffered file size data returned by the OpenLog firmware.