Problem detecting data no Serial Port

[Altera_Forum]

Hello,  

I´ve built the folowing code:  while (1) {  fprintf(fp, "%c", B_PACK);   for (j = 0; j < 10000000; j++)  {   //testadado = (testadado | tembyte()); // tem dado http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/smile.gif   if(IORD_ALTERA_AVALON_UART_STATUS(ENDSERIAL) & 0x080)  {  printf("I got data");  testadado = 1;  getchar();  break;  }  } }  Where fp is a pointer to my uart1.  Well, I´m testing this code with Hyperterminal. I can receive the B_PACK byte there with no problems. But when I send one byte thru the Hyperterminal, the code keeps running and it do not enter in the  if(IORD_ALTERA_AVALON_UART_STATUS(ENDSERIAL) & 0x080)  condition. If I send a lot of data, then sometimes it enters in the condition. But it do not work to the first data. Can someone help me?  And isn´t there another way to detect if there is data on the serial?  Thanks!

[Altera_Forum]

--- Quote Start ---  originally posted by hoffpistolao@Dec 21 2005, 08:27 AM hello,  i´ve built the folowing code:  while (1) {       fprintf(fp, "%c", b_pack);           for (j = 0; j < 10000000; j++)       {          //testadado = (testadado | tembyte());  // tem dado http://forum.niosforum.com/work2/style_emoticons/<#emo_dir#>/smile.gif          if(iord_altera_avalon_uart_status(endserial) & 0x080)         {           printf("i got data");           testadado = 1;           getchar();           break;         }   } }  where fp is a pointer to my uart1.       well, i´m testing this code with hyperterminal. i can receive the b_pack byte there with no problems. but when i send one byte thru the hyperterminal, the code keeps running and it do not enter in the  if(iord_altera_avalon_uart_status(endserial) & 0x080)  condition. if i send a lot of data, then sometimes it enters in the condition. but it do not work to the first data. can someone help me?  and isn´t there another way to detect if there is data on the serial?  thanks! <div align='right'><{post_snapback}> (index.php?act=findpost&pid=11692)  --- quote end ---    --- Quote End ---    Hello,  maybe the problem here is that you are using high-level HAL functions with low-level macros (driver level) to access your UART. If you only use one of these methods, it should work. May be if you fclose() the UART before using the low-level macros could help.   We had a similar problem because we wanted to use the high-level HAL functions only, but then the getchar() function blocked until there was data received. So we decided to write our own UART driver with a non-blocking read() function.   I hope this helps!

[Altera_Forum]

I got that. 

And is there a way to detect if there is data on serial using High level functions? Because if I use getc to read a data the program stops until the data comes. So I would like to be sure that there is data, and then use the getc().  Thank you for replying! =]

[Altera_Forum]

I haven&#39;t found a way to detect if there is a byte in the receive buffer of the UART with high-level HAL functions (like read(), getc()...) only. This was the reason why we created our own low-level driver for the UART which has a different read() function which returns immediately even if there was no data received. If this is the case, our function simply returns a value which indicates that 0 bytes are received and the calling code can continue.  

 Unfortunately I cannot give you the code of our driver because there is some other functionality in this driver which is very application-specific.

[Altera_Forum]

try this code , it check how much char are in the uart buffer  

# include "altera_avalon_uart.h"# include <fcntl.h># include <unistd.h># include "priv/alt_file.h"  int getUartBufferCnt() {   //alt_fd* fd=&alt_fd_list[fdterm];   //fd is the uart&#39;s file discreptor  alt_avalon_uart_dev* dev = (alt_avalon_uart_dev*) fd->dev;  int bufferCnt=dev->rx_end-dev->rx_start;  if(bufferCnt<0)  bufferCnt+=ALT_AVALON_UART_BUF_LEN;   return bufferCnt;  }