ALTERA_JTAG_UART(4)					   BSD Kernel Interfaces Manual 				       ALTERA_JTAG_UART(4)

NAME

     altera_jtag_uart -- driver for the Altera JTAG UART Core

SYNOPSIS

     device altera_jtag_uart

     In /boot/device.hints:
     hint.altera_jtag_uart.0.at="nexus0"
     hint.altera_jtag_uart.0.maddr=0x7f000000
     hint.altera_jtag_uart.0.msize=0x40
     hint.altera_jtag_uart.0.irq=0
     hint.altera_jtag_uart.1.at="nexus0"
     hint.altera_jtag_uart.1.maddr=0x7f001000
     hint.altera_jtag_uart.1.msize=0x40

DESCRIPTION

     The altera_jtag_uart device driver provides support for the Altera JTAG UART core, which allows multiple UART-like streams to be carried over
     JTAG.  altera_jtag_uart allows JTAG UART streams to be attached to both the low-level console interface, used for direct kernel input and
     output, and the tty(4) layer, to be used with ttys(5) and login(1).  Sequential Altera JTAG UART devices will appear as ttyu0, ttyu1, etc.

HARDWARE

     Altera JTAG UART devices can be connected to using Altera's nios2-terminal program, with the instance selected using the --instance argument
     on the management host.  altera_jtag_uart supports JTAG UART cores with or without interrupt lines connected; if the irq portion of the
     device.hints entry is omitted, the driver will poll rather than configure interrupts.

SEE ALSO

     login(1), tty(4), ttys(5)

     Altera Embedded Peripherals IP User Guide, Altera Corporation, http://www.altera.com/literature/ug/ug_embedded_ip.pdf, June 2011.

HISTORY

     The altera_jtag_uart device driver first appeared in FreeBSD 10.0.

AUTHORS

     The altera_jtag_uart device driver and this manual page were developed by SRI International and the University of Cambridge Computer Labora-
     tory under DARPA/AFRL contract (FA8750-10-C-0237) (``CTSRD''), as part of the DARPA CRASH research programme.  This device driver was written
     by Robert N. M. Watson.

BUGS

     altera_jtag_uart must dynamically poll to detect when JTAG is present, in order to disable flow control in the event that there is no receiv-
     ing endpoint.  Otherwise, the boot may hang waiting for the JTAG client to be attached, and user processes attached to JTAG UART devices
     might block indefinitely.	However, there is no way to flush the output buffer once JTAG is detected to have disappeared; this means that a
     small amount of stale output data will remain in the output buffer, being displayed by nios2-terminal when it is connected.  Loss of JTAG
     will not generate a hang-up event, as that is rarely the desired behaviour.

     nios2-terminal does not place the client-side TTY in raw mode, and so by default will not pass all control characters through to the UART.

BSD
								  August 18, 2012							       BSD