MPC8280 datasheet(1002/1386 Pages) FREESCALE

1002 / 1386 page

ATM Controller and AAL0, AAL1, and AAL5

MPC8280 PowerQUICC II Family Reference Manual, Rev. 1

31-42

Freescale Semiconductor

a VC when sending a ATM TRANSMIT command, initiating the external CAM or address compression

tables, and when the CP sends an interrupt to an interrupt queue.

Example:

Suppose a configuration supports 1,024 regular ATM channels. To allocate 4 Kbytes of dual-port RAM

space to the internal connection table, determine that channel codes 0–63 are internal (64 VCs

× 64 bytes

(RCT and TCT) = 4 K). Channels 0–1 are reserved. The remaining 962 (1024 - 62) external channels are

assigned channel codes 256–1217. See Figure 31-24.

Figure 31-24. Example of a 1024-Entry Receive Connection Table

The general formula for determining the real starting address for all internal and external connection table

entries is as follows:

Connection table base address + (channel code

× 32)

Thus, the real starting address of the RCT entry associated with channel code 3 is as follows:

INT_RCT_BASE+ (3

× 32) = INT_RCT_BASE + 96

Even though it produces a gap in the connection table, the first external channel’s real starting address of

the RCT entry (channel code 256) is as follows:

EXT_RCT_BASE+ (256

× 32) = EXT_RCT_BASE + 8192

See Section 31.10.1, “Parameter RAM,” to find all the connection table base address parameters. (The

transmit connection table base address parameters are INT_TCT_BASE, EXT_TCT_BASE,

INT_TCTE_BASE, and EXT_TCTE_BASE.)

Dual-Port RAM

INT_RCT_BASE

Reserved

RCT2

RCT3

RCT63

External Memory

EXT_RCT_BASE

RCT256

RCT257

RCT258

RCT259

RCT1217

Raw Cell (AAL0)

MPC8280 Datasheet(PDF) 1002 Page - Freescale Semiconductor, Inc