![](http://datasheet.mmic.net.cn/Exar-Corporation/XRT79L71IB-F_datasheet_100145/XRT79L71IB-F_66.png)
XRT79L71
PRELIMINARY
51
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
REV. P2.0.0
NOTES:
1.
Registers associated within each functional block are specified in ascending order (based upon the on-chip
Address Location).
No other inferences should be made regarding the order in which these registers are
presented in this table.
2.
2.For Clear-Channel Framer Applications, the Receive ATM Cell/PPP Packet Processor and Transmit ATM Cell/
PPP Packet Processor Blocks will be disabled and do not need to be included as a part of the Interrupt Service
Routine
Once the C/P has read out the contents of the appropriate registers (as listed above in Table 9), then there
may (or may not) be additional interrupt status registers to read as described below.
3.2
Interrupt Servicing for the DS3/E3 Framer Block
If, upon reading out the contents of the Operation Interrupt Status Registers that the interrupting block is the
DS3/E3 Framer block then the user should execute a READ operation to the Framer Block Interrupt Status
Register. The bit-format for the Framer Block Interrupt Status Register is as presented below.
Depending upon which of these bit-fields are set to "1", the C/P (while executing the Interrupt Service
Routine) will need to branch to reading out the appropriate register as depicted below in Table 10.
Receive ATM Cell/PPP
Packet Processor Block
Receive ATM Cell Processor Block - Receive ATM Interrupt Status Register -
Byte 1
0x170A
Receive ATM Cell Processor Block - Receive ATM Interrupt Status Register -
Byte 0
0x170B
Transmit ATM Cell/PPP
Packet Processor Block
Transmit ATM Cell Processor Block - Transmit ATM Interrupt Status Register -
Byte 1
0x1F0B
Framer Block Interrupt Status Register (Address = 0x1105)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Receive
DS3/E3
Framer
Block
Interrupt
Status
Unused
Transmit
DS3/E3
Framer
Block
Interrupt
Status
One Second
Interrupt
Status
R/O
RUR
X
0
X
TABLE 9: INTERRUPT SERVICE ROUTINE GUIDE FOR THE XRT79L71
INTERRUPT FUNCTIONAL
BLOCK
THE NEXT REGISTER TO BE READ DURING THE INTERRUPT SERVICE ROUTINE
ADDRESS
LOCATION