MC68HC705C9A_1 Datasheet, PDF (20/157 Pages) Freescale Semiconductor, Inc – General Release Specification

Freescale Semiconductor, Inc.
General Release Specification _{Configuration Options}
1.4 Configuration Options
The options and functions of the MC68HC705C9A can be configured to
emulate either the MC68HC05C9A or the MC68HC05C12A.
The ROM device MC68HC05C9A has eight ROM mask options to select
external interrupt/internal pullup capability on each of the eight port B
bits. Other optional features are controlled by software addressable
registers during operation of the microcontroller. These features are IRQ
sensitivity and memory map configuration.
On the ROM device MC68HC05C12A, all optional features are
controlled by ROM mask options. These features are the eight port B
interrupt/pullup options, IRQ sensitivity, STOP instruction disable, and
COP enable.
On the MC68HC705C9A the ROM mask options of the MC68HC05C9A
and the MC68HC05C12A are controlled by mask option registers
(MORs). The MORs are EPROM registers which must be programmed
appropriately prior to operation of the microcontroller. The software
options of the MC68HC05C9A are implemented by identical software
registers in the MC68HC705C9A.
When configured as an MC68HC05C9A:
• The entire 16K memory map of the C9A is enabled, including
dual-mapped RAM and EPROM at locations $0020–$004F and
$0100–$017F.
• C12A options in the C12MOR ($3FF1) are disabled.
• The C9A option register ($3FDF) is enabled, allowing software
control over the IRQ sensitivity and the memory map
configuration.
• The C9A COP reset register ($001D) and the C9A COP control
register ($001E) are enabled, allowing software control over the
C9A COP and clock monitor.
• The C12 COP clear register ($3FF0) is disabled.
• The port D data direction register ($0007) is enabled, allowing
output capability on the seven port D pins.
MC68HC705C9A — Rev. 2.0
General Description
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