CN8223 Datasheet, PDF (68/161 Pages) Conexant Systems, Inc – ATM Transmitter/Receiver with UTOPIA Interface

2.0 Functional Description
2.6 ATM Cell Processing
CN8223
ATM Transmitter/Receiver with UTOPIA Interface
This capability can be used to verify far-end FEBE operation. BIP generation
can be disabled via the Overhead Control bits. The fields of the G1 octet are
under control of the All 0s FEBE [bit 14], All 1s FEBE [bit 13], and Transmit
Alarm Control [bits 9–4] of CONFIG_2. The FEBE controls operate as shown in
Table 2-21.
Table 2-21. FEBE Controls
All 1s FEBE
0
0
1
1
All 0s FEBE
0
1
0
1
FEBE Field Value
BIP-8 Errors Received
0000
1111
0000
The yellow alarm bit in the G1 octet is set to the value contained in Transmit
Alarm Control [bit 7].
The C1 octet is under control of PHY Type [bits 2–0] of CONFIG_1 [0x00],
Force Cycle Stuffing [bit 6] of CONFIG_3 [0x02], and Overhead Control [bits
3–0] of CONFIG_2 [0x01] as shown in Table 2-22.
Table 2-22. C1 Octet
Disable C1
Generation
PHY Type
Force Cycle
Stuffing
C1 Octet Value
1
x
x
00
0
DS1, E1
x
00
0
DS3, E3
0
Per Selected 8 kHz Reference
(Via CONFIG_1, Bit 11)
0
DS3, E3
1
Per Default Cycle
The trailer content (except in E1 mode where there is no trailer) has each
nibble set to 1100 unless Overhead Control [bit 0] is set. In this case, each nibble
has the value 0000.
In 53-octet formats, no PLCP overhead is associated with each ATM cell. The
only overhead present is that contained in the line framing format, as discussed in
Section 2.2.
2-34
Conexant
100046C