UART RS232 receive missing bytes

Hi,

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I have experience missing receive bytes using UART RS232 port on uClinux running NIOS2 /f. I implemented a loopback application to send 128 bytes hex data from ttyA0 (RS232 port) and receive on ttyA5 (RS232 port). This is a DE2-115 development kit. The IRQ for both port is 1 and 2. I have a JTAG for nios2-terminal, but it's irq is 3. I have disabled the flow control (ctsrts, xon/xoff,etc), but each loopback test I do, I always missing 10 to 11 bytes. However, if I send less than 10 bytes of data, I have higher chance of success getting the same bytes across. I have heard I need a FIFO MEGAIP for the design but there no current uClinux driver support it. If you know of this problem and have a solution to it, please kindly let me know what I am missing?

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At first, please check whether the rx buffer overflow is happend really or not by e.g. 'cat /proc/tty/device/altera_uart' etc. If you want to use an UART IP with FIFO, please check the next page.

http://alterawiki.com/wiki/fifoed_avalon_uart

This IP has the same registers as the normal UART, and maybe we can use the same UART driver. I tested it under the next configuration and at least, it works.

Kazu