M68HC16 Z SERIES
SYSTEM INTEGRATION MODULE
USER’S MANUAL
5-49
Internal single byte or aligned word writes are guaranteed valid for synchronous re-
sets. External writes are also guaranteed to complete, provided the external configu-
ration logic on the data bus is conditioned as shown in
5.7.3 Reset Mode Selection
The logic states of certain data bus pins during reset determine SIM operating config-
uration. In addition, the state of the MODCLK pin determines system clock source and
the state of the BKPT pin determines what happens during subsequent breakpoint as-
sertions.
is a summary of reset mode selection options.
Table 5-18 Reset Source Summary
Type
Source
Timing
Cause
Reset Lines Asserted by
Controller
External
External
Synch
RESET pin
MSTRST
CLKRST
EXTRST
Power up
EBI
Asynch
V
DD
MSTRST
CLKRST
EXTRST
Software watchdog
Monitor
Asynch
Time out
MSTRST
CLKRST
EXTRST
HALT
Monitor
Asynch
Internal HALT assertion
(e.g. double bus fault)
MSTRST
CLKRST
EXTRST
Loss of clock
Clock
Synch
Loss of reference
MSTRST
CLKRST
EXTRST
Test
Test
Synch
Test mode
MSTRST
—
EXTRST
Table 5-19 Reset Mode Selection
Mode Select Pin
Default Function
(Pin Left High)
Alternate Function
(Pin Pulled Low)
DATA0
CSBOOT 16-Bit
CSBOOT 8-Bit
DATA1
CS0
CS1
CS2
BR
BG
BGACK
DATA2
CS3
CS4
CS5
FC0
FC1
FC2
DATA3
DATA4
DATA5
DATA6
DATA7
CS6
CS[7:6]
CS[8:6]
CS[9:6]
CS[10:6]
ADDR19
ADDR[20:19]
ADDR[21:19]
ADDR[22:19]
ADDR[23:19]
DATA8
DSACK[1:0],
AVEC, DS, AS,
SIZ[1:0]
PORTE
DATA9
IRQ[7:1]
MODCLK
PORTF
DATA11
Normal Operation
1
NOTES:
1. DATA11 must remain high during reset to ensure normal operation.
Reserved
MODCLK
VCO = System Clock
EXTAL = System Clock
BKPT
Background Mode Disabled
Background Mode Enabled
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Freescale Semiconductor, Inc.
For More Information On This Product,
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