XRT74L73 Datasheet, PDF (178/488 Pages) Exar Corporation – 3 CHANNEL, ATM UNI/PPP DS3/E3 FRAMING CONTROLLER

XRT74L73
3 CHANNEL, ATM UNI/PPP DS3/E3 FRAMING CONTROLLER
REV. P1.0.1
FIGURE 47. DS3 FRAME FORMAT FOR C-BIT PARITY
PRELIMINARY
P
I
F1
I
CP
I
F0
I
CP
I
F0
I
CP
I
F1
I
P
I
F1
I FEBE I
F0
I FEBE I
F0
I FEBE I
F1
I
M0
I
F1
I
DL
I
F0
I
DL
I
F0
I
DL
I
F1
I
M1
I
F1
I UDL I
F0
I UDL I
F0
I UDL I
F1
I
M0
I
F1
I UDL I
F0
I UDL I
F0
I UDL I
F1
I
X = Signaling bit for network control
I = Payload Information (84 bit packets)
Fi = Frame synchronization bit with logic value i
P = Parity bit
Mi = Multiframe synchronization bit with logic value i
AIC = Application Identification Channel
NA = reserved for network application
FEAC = Far End Alarm and Control
DL = Data Link
CP = CP (Path)-bit parity
FEBE = Far End Block Error
UDL = User Data Link
FIGURE 48. DS3 FRAME FORMAT FOR M13
X
I
F1
I C11 I
F0
I C12 I
F0
I C13 I
F1
I
I
X
I
F1
I C21 I
F0
I C22 I
F0
I C23 I
F1
I
P
I
F1
I C31 I
F0
I C32 I
F0
I C33 I
F1
I
P
I
F1
I C41 I
F0
I C42 I
F0
I C43 I
F1
I
M0
I
F1
I C51 I
F0
I C52 I
F0
I C53 I
F1
I
M1
I
F1
I C61 I
F0
I C62 I
F0
I C63 I
F1
I
M0
I
F1
I C71 I
F0
I C72 I
F0
I C73 I
F1
I
X = Signaling bit for network control
Mi = multiframe synchronization bit with logic values i
I = Payload Information (84 bit packets)
Fi = Frame synchronization bit with logic value i
Cij = jth stuff code bit of ith channel
To choose between these two frame formats, write
the appropriate data to bit 2 of the Framer Operating
Mode Register (Address = 0x00), as depicted below.
P = Parity bit
FRAMER OPERATING MODE REGISTER (ADDRESS = 0X00)
BIT 7
BIT 6
BIT 5
Local Loopback DS3/E3* Internal LOS
Enable
BIT 4
RESET
BIT 3
Interrupt
Enable Reset
BIT2
Frame Format
BIT 1
BIT 0
TimRefSel[1:0]
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