MC68HC908AZ32ACFU MOTOROLA [Motorola, Inc], MC68HC908AZ32ACFU Datasheet - Page 186

• Manufacturer Part Number: MC68HC908AZ32ACFU
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

Monitor ROM (MON)
Advance Information
186
NOTE:
If the received bytes match those at locations $FFF6–$FFFD, the host
bypasses the security feature and can read all FLASH locations and
execute code from FLASH. 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.
If the received bytes do not match the data at locations $FFF6–$FFFD,
the host fails to bypass the security feature. The MCU remains in monitor
mode, but reading FLASH locations returns undefined data, and trying
to execute code from FLASH causes an illegal address reset. After the
host fails to bypass security, any reset other than a power-on reset
causes an endless loop of illegal address resets.
After receiving the eight security bytes from the host, the MCU transmits
a break character signalling that it is ready to receive a command.
The MCU does not transmit a break character until after the host sends
the eight security bytes.
V
RST
NOTE: 1 = Echo delay (2 bit times)
DD
PA0
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
Figure 12-6. Monitor Mode Entry Timing
FROM HOST
Monitor ROM (MON)
FROM MCU
4096 + 32 CGMXCLK CYCLES
1
24 BUS CYCLES (MINIMUM)
4
1
68HC908AZ32A — Rev 0.0
1
2
4
MOTOROLA
1