
PM5317 SPECTRA-9953 Telecom Standard Product Data Sheet
Release
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2000741, Issue 5
513
Figure 37 Add System Bus Functional Timing
ADX[N]+/
ADX[N]-
...
SYSCLK
AFP
S4,3/
A2
S1,1/J0
S2,1/
Z0
S4,3/
A2
S1,1/J0
S2,1/
Z0
AFPDLY[13:0] Delay
...
...
...
...
...
Max Delay between
First and Last J0s
Max Delay until internal Frame Pulse
...
...
...
Min Delay until internal
Frame Pulse
ADY[M]+/
ADY[M]-
18.3
System Drop Interface Timing
Figure 38 shows the delay from assertion of DFP to the drop serial data links. Due to the
presence of FIFOs in the data path, the maximum delay to the J0 character being output on the
serial drop lines is 16 SYSCLK cycles. The minimum delay is eight SYSCLK cycles. DFPO is
asserted high to indicate the J0 character emission on the Drop bus. DFPO may pulse more than
once if the delay between J0s emission is more than two bytes. In order to align the 16 links, the
T8TE center bit may be used upon system startup. An internal software delay register
(DFPDLY_REG[13:0]) is used to internally delay the external DFP pulse, thus delaying the
emission of the J0 characters on the serial Drop bus.
Also note that changes to DFPDLY[13:0] will only take effect after a DFP pulse has been
received, (and while DFP_DISABLE is not set to 1).
Figure 38 Drop System Interface Timing
DDP[N]/
DDN[N]
...
SYSCLK
DFP
S4,3/
A2
S1,1/J0
S2,1/
Z0
Min Delay (8 cycles + DFPDLY_REG[13:0] x Tsysclk) ,
Max Delay(16 cycles + DFPDLY_REG + Tsysclk)
to J0 character
...
...
...
...
DFPO
...