External Core Complex Interfaces
e200z3 Power Architecture Core Reference Manual, Rev. 2
Freescale Semiconductor
7-59
shows the relationships among p_iack, the interrupt request inputs, and exception vector
fetching.
Figure 7-32. Interrupt Acknowledge Operation Case 1
In this example, an external input interrupt is requested in cycle 1. The p_voffset[0:15] inputs are driven
with the vector offset for ‘A’, and p_avec_b is negated, indicating vectoring is desired. For this example,
the bus is idle at the time of assertion. The CPU may sample a requested interrupt as early as the cycle in
which it is initially requested, and it does so in this example. The interrupt request,the vector offset, and
the autovector input are sampled at the end of cycle 1. In cycle 3, the interrupt is acknowledged by the
assertion of the p_iack output, indicating that the values present on interrupt inputs at the beginning of
cycle 2 have been internally latched and committed for servicing. Note that the interrupt vector lines have
changed to a value of ‘B’ during cycle 2, and the p_critint_b input has been asserted by the interrupt
controller. The vector number and autovector signals must be consistent with the higher priority critical
input request, and thus must change when the state of the interrupt request inputs change. The p_iack
output assertion in cycle 3 indicates that the values present at the rise of cycle 2 (vector ‘A’) have been
committed to. During cycle 3, the CPU begins instruction fetching of the handler for vector ‘A’. The new
pair
vec A
vec B
A handler
A +8
A +16
idle
1 outst.
2 outst.
1st inst pair
int A handlr
A hand + 8
int A hand addr
int A hand + 8
1
2
3
4
5
m_clk
p_critint_b
p_extint_b
p_voffset[0:15]
sample point
p_iack
p_avec_b
p_treq_b
p_addr
attributes
p_r
/
w
p_tbusy_b
p_data_in
p_ta_b
mmu access
cache access
cache miss