PM8621 datasheet(148/184 Pages) PMC

148 / 184 page

NSE-8G™ Standard Product Data Sheet

Preliminary

Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use

147

Document ID: PMC-2010850, Issue 1

Warning: Attempting a page copy while a page swap is pending can lead to corruption of

both online and offline memory pages if the page swap occurred while the page copy is in

progress.

12.7 Telecombus Mode Operation

In Telecombus mode operation, only 1080 words of the configuration RAM are utilized. This

same configuration is repeated nine times for switching the entire 9720 byte OC-12 frame. In this

mode, RC1FP is flywheeled internally every frame so that page swaps can also occur at this

frequency. The OC1FP output pulse that is used to resynchronize external TSBs occurs at every

4th frame.

To configure this mode of operation, use the following programming steps. Note, the order in

which these steps are followed is irrelevant.

1. Program the DCB Frame Size register (0x4A) to 1079.

° This programs the DCB to use just 1080 location of the RAMs.

2. Program the DCB MF_SWAP bits in Configuration register (0x4C) to 00.

° This will program the DCB to effect page changes at every 9720 byte frame when a page

swap request is received.

° OC1FP will be output at every 4

th frame.

° CMP inputs will be sampled every frame at the internally flywheeled RC1FP location.

° If enabled, FRAMEI will occur every frame at the internally flywheeled RC1FP location.

12.8 SBI Column Mode Operation

In SBI column mode operation, only 1080 rows of the configuration RAM is utilized, this same

configuration is repeated nine times for switching the entire 9720 byte OC12 frame and 36 times

to form the 4-frame multiframe. In this mode, RC1FP is flywheeled internally every fourth frame

so that page swap can also occur at this frequency. OC1FP output that is used to resynchronize

external TSBs also occurs at every fourth frame.

To configure this mode of operation, use the following programming steps. Note, the order in

which these steps are followed is irrelevant.

1. Program the DCB Frame Size register (0x04A) to 1079.

° This programs the DCB to use just 1080 location of the RAMs.

2. Program the MF_SWAP bits in DCB Configuration register (0x04C) to 01.

° This will program the DCB to effect page changes at every 4 x 9720 frame when a page

swap request is received.

° OC1FP will be output at every 4 frame.

° CMP inputs will be sampled every 4 frame at the internally flywheeled RC1FP location.

PM8621 Datasheet(PDF) 148 Page - PMC-Sierra, Inc