Datasheet

Monitor ROM (MON)
MC68HC908GR16 Data Sheet, Rev. 5.0
Freescale Semiconductor 243
• If $FFFE and $FFFF contain $FF (erased state):
– The external clock is 32.768 kHz
–IRQ
= V
SS
The last two conditions are the forced monitor mode.
Figure 19-9. Simplified Monitor Mode Entry Flowchart
MONITOR MODE ENTRY
POR RESET
PTA0 = 1, PTA1 = 0,
PTB0 = 1, AND
PTB1 = 0?
IRQ = V
TST
?
PTA0 = 1,
PTA1 = 0, RESET
BLANK?
YES
NO
YES
NO
FORCED
MONITOR MODE
NORMAL
USER MODE
NORMAL
MONITOR MODE
FACTORY
USE ONLY
NO NO
SEND 8 BYTES
SECURITY
IS RESET
POR?
YES
YES
YES
NO
ARE ALL
SECURITY BYTES
CORRECT?
NO
YES
ENABLE FLASH
DISABLE FLASH
EXECUTE
MONITOR CODE
DOES RESET
OCCUR?
CONDITIONS
FROM Table 19-1
DEBUGGING
AND FLASH
PROGRAMMING
(IF FLASH
IS ENABLED)