Motorola MPC8260 User Manual

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Chapter 27.  Multi-Channel Controllers (MCCs)  
27-17
Part IV.  Communications Processor Module
27.10  MCC Exceptions
MCC interrupt handling involves two main data structures, the MCC event register
(described in Section 27.10.1, ÒMCC Event Register (MCCE)/Mask Register (MCCM))
and the interrupt circular tables, shown in Figure 27-12. 
 
Figure 27-12. Interrupt Circular Table
There is one table for transmitter interrupts and from one to four tables for receiver
interrupts. Each channel is programmed to report receiver interrupts in one of the receiver
tables. This way receiver interrupts can be sorted, for example, by priority. Each interrupt
circular table must be least two entries long.
T/RINTBASE and T/RINTPTR, which are user-initialized global MCC parameters (See
Section 27.3, ÒGlobal MCC ParametersÓ), point to the starting location of the table (in
external memory) and the current empty position (initialized at the top of the table)
available to the CP. All the entries in the table must be user-initialized with 0x00000000,
except for the last one which must be initialized with 0x40000000 (W = 1, thus deÞning the
Table 27-12. Receive Commands 
Command
Description 
STOP
 
RECEIVE
Forces the receiver of the selected channel to terminate reception. After this command is executed, the 
CP does not change the receive parameters in the dual-port RAM. The user must initialize the channel 
receive parameters in order to restart reception.
INIT
 
RX
 
PARAMETERS
 
Initializes all receive parameters in this MCC parameter RAM to their reset state. Should be issued only 
when the receiver is disabled. Note that the MCC initialize commands initialize only the 32 consecutive 
channels starting with the channel number speciÞed in CPCR[MCN]. To initialize more than 32 
channels, reissue the command with the appropriate channel numbers. Note also the 
INIT
 
TX
 
AND
 
RX
 
PARAMETERS
 command can be used to reset both the receive and transmit parameters.
V=0
W=0
Interrupt Flags
Channel Number
T/RINTBASE
V=0
W=0
Interrupt Flags
Channel Number
V=0
W=0
Interrupt Flags
Channel Number
V=0
W=0
Interrupt Flags
Channel Number
V=1
W=0
Interrupt Flags
Channel Number
V=1
W=0
Interrupt Flags
Channel Number
V=0
W=0
Interrupt Flags
Channel Number
V=0
W=0
Interrupt Flags
Channel Number
V=0
W=1
Interrupt Flags
Channel Number
T/RINTPTR
Software Pointer
0
1
2Ð17
18Ð25
26Ð31
Interrupt Table Entry