MC68HC08AZ32A Datasheet, PDF (278/312 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Development Support
19.3.1 Functional Description
Figure 19-7 shows a simplified diagram of monitor mode entry.
The monitor module receives and executes commands from a host computer. Figure 19-8 shows an
example circuit used to enter monitor mode and communicate with a host computer via a standard
RS-232 interface.
POR RESET
CONDITIONS
FROM Table 19-1
DEBUGGING
AND EEPROM
PROGRAMMING
(IF EEPROM
IS ENABLED)
278
NO
IRQ = V_TST?
NORMAL
USER MODE
YES
PTA0 = 1,
NO
PTC0 = 1, AND
PTC1 = 0?
YES
NORMAL
MONITOR MODE
INVALID
USER MODE
HOST SENDS
8 SECURITY BYTES
IS RESET
POR?
NO
YES
YES
ARE ALL
SECURITY BYTES
NO
CORRECT?
ENABLE ROM
DISABLE ROM
MONITOR MODE ENTRY
EXECUTE
MONITOR CODE
YES
DOES RESET
NO
OCCUR?
Figure 19-7. Simplified Monitor Mode Entry Flowchart
MC68HC08AZ32A Data Sheet, Rev. 2
Freescale Semiconductor