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RELEASED
DATA SHEET
PM7382 FREEDM-32P256
ISSUE 3
PMC-2010333
FRAME ENGINE AND DATA LINK MANAGER 32P256
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA,INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
292
Figure 31 – Channelised T1/J1 Transmit Link Timing
TCLK[n]
TD[n]
B7 B8
B1
B2 B3 B4 B5 B6 B7 B8 B1 B2 B3
TS 24
TS 1
TS 2
F
The timing relationship of the transmit clock (TCLK[n]) and data (TD[n]) signals
of a channelised E1 link is shown in Figure 32. The transmit data stream is an
E1 frame with a singe framing byte (FAS/NFAS in Figure 32) followed by octet
bound time-slots 1 to 31. TCLK[n] is held quiescent during the framing byte.
The most significant bit of each time-slot is transmitted first (B1 in Figure 32).
The least significant bit of each time-slot is transmitted last (B8 in Figure 32).
The TD[n] bit (B8 of TS31) before the framing byte is the least significant bit of
time-slot 31. In Figure 32, the quiescent period is shown to be a low level on
TCLK[n]. A high level, effected by extending the high phase of bit B8 of time-slot
31, is equally acceptable. In channelised E1 mode, TCLK[n] can only be gapped
during the framing byte. It must be active continuously at 2.048 MHz during all
time-slot bits. Time-slots that are not provisioned to belong to any channel
(PROV bit in the corresponding word of the transmit channel provision RAM in
the TCAS256 block set low) transmit the contents of the Idle Time-slot Fill Data
register.
Figure 32 – Channelised E1 Transmit Link Timing
TCLK[n]
TD[n]
B6 B7
B1
B2 B3
TS 31
FAS / NFAS
TS 1
B8
B4 B5 B6 B7 B8 B1 B2 B3 B4
TS 2
13.5 PCI Interface
A PCI burst read cycle is shown In Figure 33. The cycle is valid for target and
initiator accesses. The target is responsible for incrementing the address during
the data burst. The 'T' symbol stands for a turn around cycle. A turn around
cycle is required on all signals which can be driven by more than one agent.
During Clock 1, the initiator drives FRAMEB to indicate the start of a cycle. It
also drives the address onto the AD[31:0] bus and drives the C/BEB[3:0] lines
with the read command. In the example below, the command would indicate a
burst read. The IRDYB, TRDYB and DEVSELB signals are in turnaround mode
(i.e. no agent is driving the signals for this clock cycle). This cycle on the PCI
bus is called the address phase.