MC68HC908GZ8 Datasheet, PDF (160/344 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Monitor ROM (MON)
V_DD
4096 + 32 CGMXCLK CYCLES
RST
FROM HOST
PA0
5
FROM MCU
1
4
1
1
2
4
1
Notes:
1 = Echo delay, approximately 2 bit times
2 = Data return delay, approximately 2 bit times
4 = Wait 1 bit time before sending next byte
5 = Wait until the monitor ROM runs
Figure 15-9. Monitor Mode Entry Timing
To determine whether the security code entered is correct, check to see if bit 6 of
RAM address $40 is set. If it is, then the correct security code has been entered
and FLASH can be accessed.
If the security sequence fails, the device should be reset by a power-on reset and
brought up in monitor mode to attempt another entry. After failing the security
sequence, the FLASH module can also be mass erased by executing an erase
routine that was downloaded into internal RAM. The mass erase operation clears
the security code locations so that all eight security bytes become $FF (blank).
Data Sheet
160
Monitor ROM (MON)
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MC68HC908GZ8
MOTOROLA