MC68HC711K4CFN4 Datasheet, PDF (25/80 Pages) Motorola, Inc – 8-Bit Microcontroller

CONFIG —System Configuration Register
$003F
Bit 7
6
ROMAD
1
RESET:
—
1
5
CLKX
—
4
PAREN
—
3
NOSEC
—
2
NOCOP
—
1
ROMON
—
Bit 0
EEON
—
ROMAD —ROM/EPROM Mapping Control
In single-chip mode ROMAD is forced to one out of reset.
0 = ROM/EPROM located at $2000–$7FFF
1 = ROM/EPROM located at $A000–$FFFF
Bit 6 —Not implemented
Always reads one
CLKX —XOUT Clock Enable
0 = XOUT pin disabled
1 = Buffered XTAL signal (four times E frequency) driven out on the XOUT pin
PAREN —Pull-Up Assignment Register Enable
0 = Pull-ups always disabled regardless of state of bits in PPAR
1 = Pull-ups either enabled or disabled through PPAR
NOSEC —Security Disable
NOSEC is invalid unless the security mask option is specified before the MCU is manufactured. If se-
curity mask option is omitted NOSEC always reads one. Refer to 3.6 Security Feature.
0 = Security enabled
1 = Security disabled
NOCOP —COP System Disable
Resets to programmed value
0 = COP enabled (forces reset on timeout)
1 = COP disabled (does not force reset on timeout)
ROMON —ROM/EPROM Enable
In single-chip mode, ROMON is forced to one out of reset. In special test mode, ROMON is forced to
zero out of reset.
0 = ROM/EPROM removed from memory map
1 = ROM/EPROM present in memory map
EEON —EEPROM Enable
0 = EEPROM disabled from memory map
1 = EEPROM present in memory map with location depending on value specified in EE[3:0] in INIT2
3.6 Security Feature
The security feature protects memory contents from unauthorized access. Although many devices in
the M68HC11 family support the security feature, an enhancement has been added to the MC68S11K4
that protects the contents of EPROM/OTPROM.
The security feature affects how the MCU behaves in certain modes. When the optional security feature
has been specified prior to manufacture and enabled via the NOSEC bit in CONFIG, the MCU is re-
stricted to operation in single-chip modes only. When the NOSEC bit equals zero, the MCU ignores the
state of the MODA pin during reset. This allows the MCU to be operated in single-chip and bootstrap
modes only. These modes of operation do not allow external visibility of the internal address and data
buses. Although the security feature can easily be disabled when in bootstrap mode, the bootloader
firmware residing in bootstrap ROM checks to see if the NOSEC bit is clear. If NOSEC is clear (security
enabled), the bootloader program performs the following:
M68HC11 K Series
MC6HC11KTS/D
MOTOROLA
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