Altera Embedded Peripherals IP - Manual (Page 79)

The small driver is a polled implementation that waits for the UART hardware before sending and
receiving each character. There are two ways to enable the small footprint driver:
• Enable the small footprint setting for the HAL system library project. This option affects device drivers
for all devices in the system as well.
• Specify the preprocessor option
-DALTERA_AVALON_UART_SMALL
. You can use this option if you want
the small, polled implementation of the UART driver, but do not want to affect the drivers for other
devices.
Refer to the help system in the Nios II IDE for details about how to set HAL properties and preprocessor
options.
If the CTS/RTS flow control signals are enabled in hardware, the fast driver automatically uses them. The
small driver always ignores them.
ioct() Operations
The UART driver supports the
ioctl()
function to allow HAL-based programs to request device-specific
operations. The table below defines operation requests that the UART driver supports.
Table 8-4: UART ioctl() Operations
Request Description
TIOCEXCL
Locks the device for exclusive access. Further calls to
open()
for this device will
fail until either this file descriptor is closed, or the lock is released using the
TIOCNXCL ioctl
request. For this request to succeed there can be no other
existing file descriptors for this device. The parameter
arg
is ignored.
TIOCNXCL
Releases a previous exclusive access lock. The parameter
arg
is ignored.
Additional operation requests are also optionally available for the fast driver only, as shown in Optional
UART ioctl() Operations for the Fast Driver Only Table. To enable these operations in your program,
you must set the preprocessor option
-DALTERA_AVALON_UART_USE_IOCTL
.
Table 8-5: Optional UART ioctl() Operations for the Fast Driver Only
Request Description
TIOCMGET
Returns the current configuration of the device by filling in the contents of the input
termios structure.
A pointer to this structure is supplied as the value of the parameter
opt
.
TIOCMSET
Sets the configuration of the device according to the values contained in the input
termios structure.
A pointer to this structure is supplied as the value of the parameter
arg
.
Note: The termios structure is defined by the Newlib C standard library. You can find the definition in
the file <Nios II EDS install path> /components/altera_hal/HAL/inc/sys/termios.h .
8-10 ioct() Operations
UG-01085
2014.24.07
Altera Corporation UART Core
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