PM73121ꢀAAL1gator II
Data Sheet
PMC-Sierra, Inc.
PMC-980620
,VVXHꢀꢁ
AAL1 SAR Processor
Figure 24 shows an example of the payload generation process.
TALP builds (segments) cell
from T_DATA_BUFFER. In
this case from DS0s 6 and 7.
TFTC writes the bytes in
Channel
pairs into T_DATA_BUFFER
6
7
31
0
0
T_DATA_BUFFER
RL_SER
5
6
7
8
9
10
. . . .
. . . .
Frames
127
Figure 24. Payload Generation
3.4 Transmit UTOPIA Interface Block (TUTOPIA)
The TUTOPIA block (shown in Figure 10 on page 24) conveys the cells emitted by the TALP to
the UTOPIA interface. Depending on the value of PHY_ENABLE input pin (refer to “PHY_
ENABLE” on page 81), the UTOPIA interface will either act as an ATM side (controls the write
enable signal) or as a PHY side (controls the cell available signal). As a PHY-side device, the
TUTOPIA block can also act as an SPHY device or a MPHY device (refer to Appendix B, “Ref-
erences”, on page 203 for the UTOPIA Level 2 specification version), depending on the value of
the SPHY_EN bit in COMP_LIN_REG. The SPHY_EN bit will default to off, so if the UTOPIA
interface is being used in an MPHY environment, there will be no contention while the device is
in software reset.
In ATM mode, the TUTOPIA block sources TATM_DATA(7:0), TATM_SOC, and /TATM_EN
while receiving /TATM_FULL. The Start-Of-Cell (SOC) indication is generated coincident with
the first byte of each cell that is transmitted on TATM_DATA. TATM_DATA and TATM_SOC
are driven at all times. The write enable signal indicates which clock cycles contain valid data for
the UTOPIA bus. The device will not assert the /TATM_EN signal until it has a full cell to send.
ꢃꢀ
PMC [ PMC-SIERRA, INC ]
