mc68hc908qf4 Freescale Semiconductor, Inc, mc68hc908qf4 Datasheet - Page 174

• Manufacturer Part Number: mc68hc908qf4
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

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Data Sheet
174
To determine whether the security code entered is correct, check to see if bit 6 of
RAM address $80 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).
V
RST
PA0
Notes:
DD
1 = Echo delay, approximately 2 bit times
2 = Data return delay, approximately 2 bit times
3 = Wait 1 bit time before sending next byte
4 = Wait until clock is stable and monitor runs
Freescale Semiconductor, Inc.
For More Information On This Product,
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Go to: www.freescale.com
Figure 16-19. Monitor Mode Entry Timing
4096 + 32 CGMXCLK CYCLES
FROM MCU
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