ox16pci958 Oxford Electrical Products, ox16pci958 Datasheet - Page 30

• Manufacturer Part Number: ox16pci958
• Description: Octal Uart With Interface
• Manufacturer: Oxford Electrical Products

OXFORD SEMICONDUCTOR LTD.
Scratchpad Register (SCR)
The 8-bit read/write scratch register has no
affect on either channel in the UART. It is
intended to be used by the programmer to hold
data temporarily.
Inverted Scratchpad Register (ISCR)
Writes to this register set the scratchpad
register. Reads return the current scratch
register value with all bits inverted.
Wake Event Enable Register (WER)
This register controls the serial port events that
can trigger a wake event, e.g. on the PCI bus.
One wake event source requires the UART's
clock to be running, but five are entirely
asynchronous and require no clock.
The wake event from the UART is a rising edge
on the wake output: it is the job of external
circuitry to latch this signal if needed.
DS-0022 Nov 05
Bit
7
4
3
2
1
0
Description
1—a wake event is generated whenever an
enabled interrupt event occurs. Requires the
UART clock to be running
1—a wake event tis generated whenever
SIN goes low
1—a wake event is generated whenever
DCD# has a changed state since the last
time the UART was clocked
1—a wake event is generated whenever RI#
goes low
1—a wake event is generated whenever
DSR# has a changed state since last time
the UART was clocked
1—a wake event is generated whenever
CTS# has a changed state since the last
time the UART was clocked
External—Free Release
4.9.
A "Shared Interrupt Status Register" (SISR)
function can be enabled. The purpose of this
function is to help device drivers arbitrate
between the multiple UARTs that may be
requesting an interrupt service. The function
consists of a single 8-bit read-only register. The
binary value of this value will either be FFh,
indicating that there is no UART requesting an
interrupt service, or a value from 0 to 7 inclusive
indicating the number of the UART that the
device driver should service next. This value is
determined using a round-robin algorithm.
There is no requirement to use the SISR
function, UARTs may be serviced in any order—
the SISR is only included as an aid to fair
servicing of the ports.
SISR Function
OX16PCI958 DATA SHEET
Page 30