MC68HC908AB32CFU Freescale Semiconductor, MC68HC908AB32CFU Datasheet - Page 168

• Manufacturer Part Number: MC68HC908AB32CFU
• Description: IC MCU 8MHZ 32K FLASH 64-QFP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68HC908AB32CFU

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: SCI, SPI
• Peripherals: POR, PWM
• Number Of I /o: 51
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 8x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-QFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Monitor ROM (MON)
10.6 Extended Security
Technical Data
168
NOTE:
NOTE:
Upon power-on reset, if the received bytes of the security code 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 a
FLASH location returns an invalid value and trying to execute code from
FLASH causes an illegal address reset. After receiving the eight security
bytes from the host, the MCU transmits a break character, signifying that
it is ready to receive a command.
To determine whether the security code entered is correct, check to see
if bit 6 of RAM address $50 is set. If it is, then the correct security code
has been entered and FLASH can be accessed.
The MCU does not transmit a break character until after the host sends
the eight security bits.
If the host fails the security bypass as described in
MCU remains in monitor mode, but reading a FLASH location returns an
invalid value and trying to execute code from FLASH causes an illegal
address reset. The MCU monitor commands are still valid and user
software can execute from RAM. A bulk-erase operation is possible,
erasing the entire FLASH memory, including the security bytes at
$FFF6–$FFFD.
To further disable monitor mode functions, an extended security
command keyword can be programmed at FLASH locations
$FFC0–$FFC7. The keyword is eight bytes long with a 7-byte ASCII
string and 1-byte $00 delimiter. The keyword for the MC68HC908AB32
MCU is "PSWDOPT" + $00.
Entry to monitor mode with extended security command keyword
programmed, the MCU stops communicating with the host after
transmitting a break character if the host fails the security bypass as
described in
Once the extended security command keyword is programmed, the
FLASH memory cannot be erased without a valid security code
(matching $FFF6–$FFFD). Therefore, the extended security command
keyword should not be programmed during software development.
10.5
Monitor ROM (MON)
Security.
MC68HC908AB32
Freescale Semiconductor
10.5
Security, the
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Rev. 1.1