IBM PowerPC 405GP User Manual page 627

IROP IROO ICT
* * *
t
t t
BCS LA PT
Figure 22-11. IICO Extended Status Register (IICO_EXTSTS)
0 IRQP IRQ Pending
• IICO_EXTSTS[IRQP] might be set
o
No IRQ is pending.
momentarily while an IRQ moves from
1 An IRQ is active, another IRQ is on-deck,
the Pending to the On-deck state.
and another interrupt-generating
• An interrupt remains pending,
condition has occurred.
IICO_EXTSTS[IRQP]=1, until the current
on-deck interrupt becomes active,
IICO_STS[lRQD]=O and
IICO_STS[IRQA]]=1.
• Writing 1 to IICO_EXTSTS[IRQP] clears
the field.
• When the IIC interrupt is disabled,
IICO_MDCNTL[IRQP] = 0,
IICO_EXTSTS[IRQP] should be ignored.
1:3 BCS Bus Control State Read-only.
000 Unused; if this value is read, a major
IIC hardware problem occurred.
001 Slave-selected state; the IIC interface
has detected and decoded a slave
transfer request on the IIC bus.
010 Slave Transfer state; the IIC interface
has detected but has not decoded a
slave transfer request on the IIC bus.
011 Master Transfer state; entered after a
master transfer request has started on
the IIC bus.
100 Free Bus state; the bus is free and no
transfer request is pending.
101 Busy Bus state; the bus is busy.
110 Unknown state; value after IIC reset.
111 Unused; if this value is read, a major
IIC hardware problem occurred.
22-12 PPC405GP User's Manual Preliminary