mc68hc08az60 Freescale Semiconductor, Inc, mc68hc08az60 Datasheet - Page 151

• Manufacturer Part Number: mc68hc08az60
• Description: M68hc08 Family Of 8-bit Microcontroller Units Mcus
• Manufacturer: Freescale Semiconductor, Inc

Security
11-mon
MOTOROLA
NOTE:
A security feature discourages unauthorized reading of ROM locations
while in monitor mode. The host can bypass the security feature at
monitor mode entry by sending eight security bytes that match the bytes
at locations $FFF6–$FFFD. Locations $FFF6–$FFFD contain
user-defined data.
Do not leave locations $FFF6–$FFFD blank. For security reasons, enter
data at locations $FFF6–$FFFD even if they are not used for vectors.
During monitor mode entry, the MCU waits after the power-on reset for
the host to send the eight security bytes on pin PA0.
If the received bytes match those at locations $FFF6–$FFFD, the host
bypasses the security feature and can read all ROM locations and
execute code from ROM. Security remains bypassed until a power-on
reset occurs. After the host bypasses security, any reset other than a
power-on reset requires the host to send another eight bytes. If the reset
was not a power-on reset, the security remains bypassed regardless of
the data that the host sends.
V
RST
PA7
PA0
NOTE: 1 = Echo delay (2 bit times)
DD
Freescale Semiconductor, Inc.
For More Information On This Product,
2 = Data return delay (2 bit times)
4 = Wait 1 bit time before sending next byte.
Go to: www.freescale.com
FROM HOST
Monitor ROM (MON)
FROM MCU
4096 + 32 CGMXCLK CYCLES
Figure 6. Monitor Mode Entry Timing
24 CGMXCLK CYCLES
1
256 CGMXCLK CYCLES (ONE BIT TIME)
4
1
MC68HC08AZ60 — Rev 1.0
1
Functional Description
Monitor ROM (MON)
2
4
1
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