Problem with non-blocking UART I/O

Hi,

Here's how I have solved it:

1) Copy altera_avalon_uart_read.c file (from C:\Altera\91\ip\altera\sopc_builder_ip\altera_avalon_uart\HAL\src directory) to your local project directory (so that it's compiled with your sources and thus will override the Altera's version).

2) Modify the altera_avalon_uart_read() function's (the FAST DRIVER version at the end of the file) last line

return count;

to

if (!block && count == 0 )

return -EWOULDBLOCK;

else

return count;

This way getc() call will not block if O_NONBLOCK is used.

I remember reporting this to Altera several years ago as a bug because the JTAG UART does it like this and can handle O_NONBLOCK correctly, but the normal UART can't. But it has not been fixed yet ...

Jari