Motorola PowerQUICC II MPC8280 Series Reference Manual page 1256

IMA Programming Model
Table 34-22. IMA Link Receive Statistics Table Entry
Offset Name
0x00 ICPVIOL
0x04 OIF
34.4.6 Structures in External Memory
The IMA microcode requires supporting queue structures in external memory. These are
used for the jitter buffers (on transmission) and the delay compensation buffers (on
reception). These structures reside in a 1 megabyte memory region defined by
IMAEXTBASE, and may reside on either the 60x bus or the local bus, as defined by
IMACNTL[DSB].
34.4.6.1 Transmit Queues
Transmit queues are allocated on a per-link basis. They are circular queues of 64-byte
buffers, defined by their start and end pointers. For the transmit queue of the timing
reference link (TRL), the queue must consist of a minimum of four buffers (although it may
consist of five buffers, if consistency of data structures is desired). For the transmit queues
of non-TRL links, the queues must consist of five buffers. Queue fill and extract pointers
must be initialized by software to the start of the queue; thereafter, these pointers are
managed by the microcode. The queue pointers must be on a 64-byte aligned boundary.
bits 0-11
IMAEXTBASE
IMAEXTBASE
34-46
Freescale Semiconductor, Inc.
Width
Word IMA receive ICP violation event counter. While ILRCNTL[SES]=0,
increments each time an errored, invalid, or missing ICP cell is
received on this link. Initialize to zero at link startup.
Word Out-of-IMA frame counter. While ILRCNTL[SES]=0, increments each
time an Out-of-IMA Frame anomaly occurs on this link. Initialize to zero
at link startup.
IMAEXTBASE
bits 12-27 bits 28-31
ITQSP 0000
ITQEP 0000
Figure 34-26. IMA Transmit Queue
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Description
IMA External Structure Region
Transmit
Queue
ITQSP + TQ_SIZE - 4
64-byte boundary
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