XRT7245
DS3 UNI FOR ATM
á
PRELIMINARY
REV. 1.03
120
The XRT7245 UNI Interrupt Block comes equipped with
the following registers to support the servicing of this
wide array of potential “interrupt request” sources.
Table 6 lists these registers and their corresponding
addresses, within the UNI.
General Flow of UNI Chip Interrupt Servicing
When any of the conditions presented in Table 6
occurs (if their Interrupt is enabled), then the UNI will
generate an interrupt request to the local μP/μC by
asserting the active-low interrupt request output pin,
INT*. Shortly after the local μP/μC has detected the
activated INT* signal, it will enter into the appropriate
“user-supplied” interrupt service routine. The first
task for the local μP/μC, while running this interrupt
service routine, may be to isolate the source of the
interrupt request down to the device level (e.g.,
XRT7245 UNI Device), if multiple peripheral devices
exist in the user’s system. However, once the “inter-
rupting peripheral” device has been identified, the
next task for the local μP/μC is to determine exactly
what feature or functional section within the device
requested the interrupt.
Determine the Functional Block(s) Requesting
the Interrupt
If the interrupting device turns out to be the XRT7245
DS3 UNI, then the local
μ
C/
μ
P must determine which
‘functional block’ requested the interrupt. Hence, upon
reaching this state, one of the very first things that the
Receive UTOPIA Interface Block
Change of Cell Alignment
Rx FIFO Overrun
Rx FIFO Underrun
UNI Chip Level
One-Second Interrupt
T
ABLE
5: L
IST
OF
ALL
OF
THE
P
OSSIBLE
C
ONDITIONS
THAT
CAN
G
ENERATE
I
NTERRUPTS
WITHIN
THE
XRT7245 UNI D
EVICE
F
UNCTIONAL
B
LOCK
I
NTERRUPTING
C
ONDITION
T
ABLE
6: A L
ISTING
OF
THE
XRT7245 UNI D
EVICE
I
NTERRUPT
B
LOCK
R
EGISTERS
A
DDRESS
L
OCATION
R
EGISTER
04h
UNI Interrupt Enable Register
05h
UNI Interrupt Status Register
0Eh
Receive DS3 Configuration and Status Register
0Fh
Receive DS3 Status Register
10h
Receive DS3 Interrupt Enable Register
11h
Receive DS3 Interrupt Status Register
13h
Receive DS3 FEAC Interrupt Enable/Status Register
14h
Receive DS3 LAPD Control Register
1Ch
Transmit DS3 FEAC Configuration and Status Register
1Fh
Transmit DS3 LAPD Status/Interrupt Register
45h
Receive PLCP Interrupt Enable Register
46h
Receive PLCP Interrupt Status Register
4Eh
Receive Cell Processor Interrupt Enable Register
4Fh
Receive Cell Processor Interrupt Status Register
60h
Transmit Cell Processor Register
6Bh
Receive UTOPIA Interrupt Enable/Status Register
6Eh
Transmit UTOPIA Interrupt Enable/Status Register