Divisor register (optional), Endofpacket register (optional) – Altera Embedded Peripherals IP User Manual
Page 84

Bit
Name
Access
Description
3
IROE
RW
Enable interrupt for a receiver overrun error.
4
ITOE
RW
Enable interrupt for a transmitter overrun error.
5
ITMT
RW
Enable interrupt for a transmitter shift register empty.
6
ITRDY
RW
Enable interrupt for a transmission ready.
7
IRRDY
RW
Enable interrupt for a read ready.
8
IE
RW
Enable interrupt for an exception.
9
TRBK
RW
Transmit break. The
TRBK
bit allows an Avalon-MM master peripheral to
transmit a break character over the
TXD
output. The
TXD
signal is forced to
0 when the
TRBK
bit is set to 1. The
TRBK
bit overrides any logic level that
the transmitter logic would otherwise drive on the
TXD
output. The
TRBK
bit interferes with any transmission in process. The Avalon-MM master
peripheral must set the
TRBK
bit back to 0 after an appropriate break
period elapses.
10
IDCTS
RW
Enable interrupt for a change in
CTS
signal.
11
(1
)
RTS
RW
Request to send (
RTS
) signal. The
RTS
bit directly feeds the
RTS_N
output.
An Avalon-MM master peripheral can write the
RTS
bit at any time. The
value of the
RTS
bit only affects the
RTS_N
output; it has no effect on the
transmitter or receiver logic. Because the
RTS_N
output is logic negative,
when the
RTS
bit is 1, a low logic-level (0) is driven on the
RTS_N
output.
If the Flow Control hardware option is not enabled, the
RTS
bit always
reads 0, and writing has no effect. Refer to the Flow Control section.
12
IEOP
RW
Enable interrupt for end-of-packet condition.
Note
:
1. This bit is optional and may not exist in hardware.
divisor Register (Optional)
The value in the
divisor
register is used to generate the baud rate clock. The effective baud rate is
determined by the formula:
Baud Rate = (Clock frequency) / (divisor + 1)
The
divisor
register is an optional hardware feature. If the Baud Rate Can Be Changed By Software
hardware option is not enabled, the
divisor
register does not exist. In this case, writing
divisor
has no
effect, and reading
divisor
returns an undefined value. For more information, refer to the Baud Rate
Options section.
endofpacket Register (Optional)
The value in the
endofpacket
register determines the end-of-packet character for variable-length DMA
transactions. After reset, the default value is zero, which is the ASCII null character (\0). For more
information, refer to status Register bits for the description for the
EOP
bit.
UG-01085
2014.24.07
divisor Register (Optional)
8-15
UART Core
Altera Corporation