CN8223 Datasheet, PDF (46/161 Pages) Conexant Systems, Inc – ATM Transmitter/Receiver with UTOPIA Interface

2.0 Functional Description
2.2 Line Framers
CN8223
ATM Transmitter/Receiver with UTOPIA Interface
The input timings are all similar: RXDATI and RXSYI are sampled on the
falling edge of the input clock; and the low-to-high transition of the sync signal
occurs during the interval of the frame bit for DS1 and DS3, with the first bit of
time slot 0 for E1, and the first bit of the frame-alignment signal for E3. For
brevity, only the DS1 timing is illustrated (Figure 2-11). The timing on this
interface is similar to the timing on the transmit interface. It is compatible with
Conexant framers. The data and sync inputs can be sampled on the rising edge of
the input clock by setting Invert RX Clock Sampling [bit 8] of CONFIG_3
[0x02].
In all framed, serial line formats, the content of the framing bit positions is
ignored. RXSYI does not need to be present every frame; it can be applied at any
submultiple of the frame rate (e.g., once every ESF superframe for DS1).
Figure 2-11. Receiver DS1 Line Interface Timing
RXCKI
RXSYI
RXDATI
78 S 2 3 4 5 6 7 8 FS 2 3 4 5 67
Channel 24
Channel 1
2-12
Conexant
100046C