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Interrupts and Exceptions
e200z3 Power Architecture Core Reference Manual, Rev. 2
Freescale Semiconductor
4-25
4.6.17
System Reset
The core implements the system reset, which is not an interrupt defined in Book E. The system reset
exception is a non-maskable, asynchronous exception signaled to the processor through the assertion of
system-defined signals.
A system reset may be initiated as follows:
•
By asserting the p_reset_b input. p_reset_b must remain asserted for a period (specified in the
hardware specifications) that allows internal logic to be reset. Assertion for less than the required
interval causes unpredictable results.
•
By asserting m_por during power-on reset. m_por must be asserted during power up and must
remain asserted for a period (specified in the hardware specifications) that allows internal logic to
be reset. Assertion for less than the required interval causes unpredictable results.
•
By watchdog timer reset control
•
By debug reset control
When a reset request occurs, the processor branches to the system reset exception vector (value on
p_rstbase[0:19] concatenated with 0xFFC in e200z3 and p_rstbase[0:29]concatenated with 2’b00 in
e200z335 ) without attempting to reach a recoverable state. If reset occurs during normal operation, all
operations stop and machine state is lost. The internal state of the e200z6e200z3 after a reset is defined in
Section 2.18.4, “Reset Settings.”
For reset initiated by watchdog timer or debug reset control, the e200z6 implements TSR[WRS] or
DBSR[MRR] to help software determine the cause. Watchdog timer and debug reset control provide the
capability to assert p_resetout_b. External logic may factor this signal into p_reset_b to cause an
e200z6e200z3 reset.
shows the TSR bits associated with reset status.
DEAR
Unchanged
Vector
IVPR[32–47] || IVOR15[48–59] || 0b0000
1
Assumes that the debug interrupt is precise
2
Conditional based on HID0 control bits. If HID0[DAPUEN] = 1, RI is unaffected since DSRR0/1 are used, otherwise it is cleared
since CSRR0/1 are updated.
3
RI is cleared by all critical class interrupts using CSRR0/1 and the machine check interrupt. These interrupt handlers
should set RI early in the handler after CSRR0/1 have been saved to allow for improved recoverability.
4
Note that multiple DBSR bits may be set.
Table 4-25. Debug Interrupt Register Settings (continued)
Register
Setting Description