MOTOROLA
Chapter 27. Multi-Channel Controllers (MCCs)
27-3
Part IV. Communications Processor Module
Figure 27-1. BD Structure for One MCC
27.3 Global MCC Parameters
The global MCC parameters are described in Table 27-1.
Table 27-1. Global Multiple-Channel Parameters
Offset
1
Name
Width
Description
0x00
MCCBASE
Word
Multi-channel controller base pointer. User-initialized parameter points to the starting
address of a 512-Kbyte BD segment in external memory.
0x04
MCCSTATE
Hword Multi-channel controller state, used by the CP for global state deÞnition (reserved for
the user)
0x06
MRBLR
Hword Maximum receive buffer length (user-initialized). DeÞnes the maximum number of
bytes written to a receive buffer before moving to the next buffer for this channel.
This value must be a multiple of 8.
0x08
GRFTHR
Hword Global receive frame threshold. Used to reduce interrupt overhead that can occur
when many short HDLC frames arrive that each cause an RXF interrupt. Setting all
bits enables every interrupt event. Setting a GRFTHR value can limit the frequency
of RXF interrupts. Note that an RXF event is written to the interrupt queue on each
received frame but GINT is set only when the number of RXF events (by all
channels) reaches the GRFTHR value. This parameter does not need to be reset
after an interrupt.
0x0A
GRFCNT
Hword Global receive frame count. A decrementor counter used to implement the GRFTHR
feature. It should be initialized to the GRFTHR value. Setting all bits enables every
interrupt event. The CP writes an entry in a circular interrupt table and decrements
GRFCNT each time a frame is received. When GRFCNT underßows the CP
generates an interrupt and copy GRFTHR to GRFCNT. This parameter does not
need to be reset after an interrupt.
Channel j TxBD
Table
Channel 0 Parameter
Channel 1 Parameter
Channel j Extra
RBASE
TBASE
Global MCC
MCCBASE
DPR
Buffer Descriptor
+
+
Channel j RxBD
Table
External Memory
512 Kbytes
x8
x8
DPR_base
Table Base Address
Parameter
Parameters
Содержание MPC8260 PowerQUICC II
Страница 1: ...MPC8260UM D 4 1999 Rev 0 MPC8260 PowerQUICC II UserÕs Manual ª ª ...
Страница 32: ...xxxii MPC8260 PowerQUICC II UserÕs Manual MOTOROLA CONTENTS Paragraph Number Title Page Number ...
Страница 66: ...lxvi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA ...
Страница 88: ...1 18 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Страница 120: ...2 32 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Страница 138: ...Part II iv MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II Configuration and Reset ...
Страница 184: ...4 46 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II ConÞguration and Reset ...
Страница 202: ...Part III vi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Страница 266: ...8 34 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Страница 382: ...10 106 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Страница 392: ...11 10 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Страница 430: ...Part IV viii MOTOROLA Part IV Communications Processor Module ...
Страница 490: ...14 36 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Страница 524: ...17 10 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Страница 556: ...18 32 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Страница 584: ...19 28 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Страница 632: ...21 24 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Страница 652: ...22 20 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Страница 668: ...23 16 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Страница 758: ...27 28 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Страница 780: ...28 22 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Страница 874: ...29 94 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Страница 920: ...31 18 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Страница 980: ...A 4 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Appendixes ...
Страница 1002: ...Index 22 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA INDEX ...
Страница 1006: ......