SYSTEM INTEGRATION MODULE
M68HC16 Z SERIES
5-24
USER’S MANUAL
5.4 System Protection
The system protection block preserves reset status, monitors internal activity, and pro-
vides periodic interrupt generation.
is a block diagram of the submodule.
Figure 5-8 System Protection
5.4.1 Reset Status
The reset status register (RSR) latches internal MCU status during reset. Refer to
5.4.2 Bus Monitor
The internal bus monitor checks data size acknowledge (DSACK) or autovector
(AVEC) signal response times during normal bus cycles. The monitor asserts the in-
ternal bus error (BERR) signal when the response time is excessively long.
DSACK and AVEC response times are measured in clock cycles. Maximum allowable
response time can be selected by setting the bus monitor timing (BMT[1:0]) field in the
system protection control register (SYPCR).
SYS PROTECT BLOCK
MODULE CONFIGURATION
AND TEST
RESET STATUS
HALT MONITOR
BUS MONITOR
SPURIOUS INTERRUPT MONITOR
SOFTWARE WATCHDOG TIMER
PERIODIC INTERRUPT TIMER
2
9
PRESCALER
CLOCK
IRQ[7:1]
BERR
RESET REQUEST
RESET REQUEST
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Freescale Semiconductor, Inc.
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