Motorola MPC8260 User Manual

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Chapter 27.  Multi-Channel Controllers (MCCs)  
27-19
Part IV.  Communications Processor Module
27.10.1.1  Interrupt Table Entry
Each interrupt table entry, shown in Figure 27-14, contains information about channel-
speciÞc events. The transmit circular table shows only events caused by transmission; the
receive circular tables shows only events caused by reception.
Table 27-13. MCCE/MCCM Register Field Descriptions 
Bits
Name
Description
0
QOV0
QOVxÑReceive interrupt queue overßow. IQOV is set (and an interrupt request generated) by the 
CP whenever an overßow occurs in the transmit circular interrupt table. This occurs if the CP tries to 
update an interrupt entry that was not handled by the user (such an entry is identiÞed by V = 1).
RINTxÑReceive interrupt. When RINT = 1, the MCC generated at least one new entry in the receive 
interrupt circular table. After clearing it, the user reads the next entry from the receive interrupt 
circular table and starts processing a speciÞc channelÕs exception. The user returns from the 
interrupt handler when it reaches a table entry with V = 0.
1
RINT0
2
QOV1
3
RINT1
4
QOV2
5
RINT2
6
QOV3
7
RINT3
8Ð11
Ñ
Reserved, should be cleared.
12
TQOV
Transmit interrupt queue overßow. TQOV is set (and interrupt request generated) by the CP 
whenever an overßow occurs in the transmit circular interrupt table. This condition occurs if the CP 
attempts to write a new interrupt entry into an entry that was not handled by the user. Such an entry 
is identiÞed by V = 1.
13
TINT
Transmit interrupt. When TINT = 1, at least one new entry in the transmit interrupt circular table was 
generated by MCC. After clearing it, the user reads the next entry from the transmit interrupt circular 
table and starts processing a speciÞc channelÕs exception. The user returns from the interrupt 
handler when it reaches a table entry with V = 0.
14
GUN
Global transmitter underrun. When set, this ßag indicates that an underrun occured in the MCCÕs 
transmitter FIFO buffer. This error is fatal, since it is unknown which channels were affected. 
Following the assertion of GUN in the MCCE the MCC stops transmitting data in all channels. The 
TDM Tx line becomes idle. The MCC transmitters must be reinitialized after this error. If enabled in 
MCCM, an interrupt request is generated when GUN is set. The user must clear GUN.
15
GOV 
Global receiver overrun. When GOV = 1, an overrun occured in the MCCÕs receiver FIFO buffer. This 
error is fatal, since it is unknown which channels were affected. When GOV = 1, the MCC stops 
receiving data in all channels. No more data is transferred to memory. The MCC receivers must be 
re-initialized after this error. If enabled in MCCM, an interrupt request is generated when GOV is set. 
The user must clear GOV bit.