JTAG uart

[ecstrema]

My board does not have a uart port. Is there any way to use printf without it?

Altera's NIOS II and V use JTAG UART. Is this supported? Can be it used for printf-like calls?

[stnolting]

Hey @ecstrema!

Altera's NIOS II and V use JTAG UART.

I have never used this JTAG UART myself. As far as I understand the concept, it is not a bridge that "tunnels" the UART signals (TX & RX) through JTAG, but it is a memory-mapped device where you can read and write complete bytes via bus accesess. This also requires a special terminal program on the host side.

Is this supported? Can be it used for printf-like calls?

Sure, but it won't work with the default software framework. But you could adjust that so UART data is written/read to/from the JTAG UART module via dedicated bus accesses.

My board does not have a uart port. Is there any way to use printf without it?

Do you have any general purpose IO headers on your board? Then you could use an external UART-USB bridge (like the cheap FTDI boards).

[ecstrema]

Thanks for your detailed answer!

I have exactly two spare io ports left, so I'll use them for uart debugging.