MC68HC705C9A Datasheet, PDF (17/118 Pages) Motorola, Inc – Microcontrollers

Mask Options
$3FF1 Bit 7
6
5
4
3
2
1
Bit 0
Read:
SEC
Write:
STOPDIS C12IRQ
C12COPE
C12A
= Unimplemented
Figure 1-3. Mask Option Register 2
C12A — C12A/C9A Mode Select Bit
This read/write bit selects between C12A configuration and C9A configuration.
1 = Configured to emulate MC68HC05C12A
0 = Configured to emulate MC68HC05C9A
C12IRQ — C12A Interrupt Request Bit
This read/write bit selects between an edge-triggered only or edge- and level-triggered external
interrupt pin. If configured in C9A mode, this bit has no effect and will be forced to 0 regardless of the
programmed state.
1 = Edge and level interrupt option selected
0 = Edge-only interrupt option selected
NOTE
Any Port B pin configured for interrupt capability will follow the same edge
or edge/level trigger as the IRQ pin.
STOPDIS — STOP Instruction Disable Bit
This read-only bit allows emulation of the “STOP disable” mask option on the MC68HC05C12A. (See
5.9 COP During Stop Mode.) If configured in MC68HC05C9A mode, this bit has no effect and will be
forced to 0 regardless of the programmed state.
1 = If the MCU enters stop mode, the clock monitor is enabled to force a system reset
0 = STOP instruction executed as normal
C12COPE — C12A COP Enable Bit
This read-only bit enables the COP function when configured in MC68HC05C12A mode. If configured
in MC68HC05C9A mode, this bit has no effect and will be forced to 0 regardless of the programmed
state.
1 = When in C12A mode, this enables the C12ACOP watchdog timer.
0 = When in C12A mode, this disables the C12ACOP watchdog timer.
SEC — Security Enable Bit
This read-only bit enables the EPROM security feature. Once programmed, this bit helps to prevent
external access to the programmed EPROM data. The EPROM data cannot be verified or modified.
1 = Security enabled
0 = Security disabled
NOTE
During power-on reset, the device always will be configured as
MC68HC05C9A regardless of the state of the C12A bit.
MC68HC05C9A Advance Information Data Sheet, Rev. 4.1
Freescale Semiconductor
17