![](http://datasheet.mmic.net.cn/330000/PM7367-PI_datasheet_16444408/PM7367-PI_301.png)
DATA SHEET
PM7367 FREEDM-32P32
ISSUE 2
PMC-1991499
FRAME ENGINE AND DATA LINK MANAGER
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMER’S INTERNAL USE
287
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 TCAS block set low) transmit the contents of the Idle Time-slot Fill Data
register.
Figure 27 – 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
13.3 PCI Interface
A PCI burst read cycle is shown In Figure 28. 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.
During Clock 2, the initiator ceases to drive the AD[31:0] bus in order that the
target can drive it in the next cycle. The initiator also drives the C/BEB[3:0] lines
with the byte enables for the read data. IRDYB is driven active by the initiator to
indicate it is ready to accept the data transfer. All subsequent cycles on the PCI
bus are called data phases.
During Clock 3, the target claims the transaction by driving DEVSELB active. It
also places the first data word onto the AD[31:0] bus and drives TRDYB to
indicate to the initiator that the data is valid.
During Clock 4, the initiator latches in the first data word. The target negates
TRDYB to indicate to the initiator that it is not ready to transfer another data
word.