using open() C command in the Nios II

I'd write any data or logging info directly to standard output. I use the logging feature of PuTTy to capture the data. fopen isn't needed.

Dear Galfonz,

PuTTY is a serial terminal emulator. Google "PuTTY download" to find it. This one works fine for me but there are several others.

ok. when I captured data using HyperTerminal, I saw some jump in my data. I think my serial port have a problem. So I want to log data using open and printf. because I think by this method that serial port do not involved. what is your opinion ? in this state puTTy is similar to HyperTerminal and it do not help me.

For open and write/printf to work you need a file system. The NIOS II does not have a file system unless you include some storage device and a device driver for it. You can either log the data on the serial port as suggested. Another alternative is to use the JTAG serial port if your real serial port have issues as you described (or try to lower the serial port speed to see if it helps). Another method would be to include some serial file transfer protocol which includes error check and retry, e.g. kermit or x/y/zmodem.

When you see dropped characters, it is due to bytes being written to the serial port faster than they are output at the baud rate the port is using. At some point the FIFO will fill up and you will start losing characters. If just a few bytes are missing you could try raising the baud rate. Otherwise insert delays in your code, after every data line, or after every byte if you UART has a small FIFO. You could also see if your UART (including its driver) and USB<->serial chip implement hardware or software based flow control. See an RS232 tutorial for more info.

Thanks all. Mr. Peter i want to log data using Jtag UART. if it is not possible (I can not open a file and write to it), i should fix my UART port.Have you an idea?

The JTAG UART works just like a regular UART, but is using the JTAG connection, e.g. your USB Blaster. Note that the JTAG UART is quite slow. If you generate data faster than your UART is running you will experience data loss due to overrun. Check that your UART is fast enough to handle your data rate. You can enable the JTAG UART in your NIOS software.

Thanks Peter. I want to store up to 4-byte data per 1ms (or 32000bps). I think that i will not experience data loss. now my problem is Error by opening a file by command fopen(). But we can able to use New lib C Commands (fopen()) according to Nios II Software Developer’s Handbook. what is my mistake?

That should work if you capture binary data. But if you convert to ASCII (printf("%x")) you need 10 times the binary generation rate, which will exceed 115200 (I don't know what your actual UART rate is).