
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
490
17.5 Accessing Indirect Registers
Indirect registers are used to conserve address space in the SPECTRA-9953 device. Writing the
indirect address register accesses indirect registers.For indirect register access, the clock for the
TSB in question has to be running. The following is a summary of which clock needs to be
running for each TSB’s indirect register access.:
Table 20 Clocks for TSB Indirect Register Access
MODE
CLOCK
TSBs
SYSCLK
SHPI, RSVCA, SARC
RXCLK2
All: RHPP, RTTP_PATH, RTTP_SECTION
OC-192
TXCLK_SRC2
All TSVCA, THPP, TTTP_PATH, TTTP_SECTION
SYSCLK
SHPI, RSVCA, SARC
RXCLK1
STM16 #1: RHPP, RTTP_PATH, RTTP_SECTION
RXCLK2
STM16 #2: RHPP, RTTP_PATH, RTTP_SECTION
RXCLK3
STM16 #3: RHPP, RTTP_PATH, RTTP_SECTION
RXCLK4
STM16 #4: RHPP, RTTP_PATH, RTTP_SECTION
TX_CLK_SRC1
STM16 #1 TSVCA, THPP, TTTP_PATH, TTTP_SECTION
TX_CLK_SRC2
STM16 #2 TSVCA, THPP, TTTP_PATH, TTTP_SECTION
TX_CLK_SRC3
STM16 #3 TSVCA, THPP, TTTP_PATH, TTTP_SECTION
QUAD OC-48
TX_CLK_SRC4
STM16 #4 TSVCA, THPP, TTTP_PATH, TTTP_SECTION
The following steps should be followed for writing to indirect registers:
1. Read the BUSY bit. If it is equal to logic 0, continue to step 2. Otherwise, continue polling
the BUSY bit.
2. Write the desired configurations for the channel into the indirect data registers.
3. Write the channel number (indirect address) to the indirect address register with RWB set to
logic 0.
4. Read BUSY. Once it equals 0, the indirect write has been completed.
The following steps should be followed for reading indirect registers:
1. Read the BUSY bit. If it is equal to logic 0, continue to step 2. Otherwise, continue polling
the BUSY bit.
2. Write the channel number (indirect address) to the indirect address register with RWB set to
logic 1.