Freescale Semiconductor, Inc.
General Description
Programmable Options
• Software-programmable external interrupt sensitivity
• Bidirectional RESET pin
NOTE: A line over a signal name indicates an active low signal. For example,
RESET is active high and RESET is active low. Any reference to voltage,
current, or frequency specified in this document will refer to the nominal
values. The exact values and their tolerance or limits are specified in
Section 13. Electrical Specifications.
1.4 Programmable Options
These options are programmable in the mask option registers:
• Enabling of port B pullup devices (see 9.5.2 Mask Option
Register 1)
• Enabling of non-programmable COP watchdog (see 9.5.3 Mask
Option Register 2)
These options are programmable in the option register (see Figure 1-1):
• One of four selectable memory configurations
• Programmable read-only memory (PROM) security1
• External interrupt sensitivity
Address: $1FDF
Bit 7
RAM0
0
6
RAM1
0
5
0
0
4
0
0
3
SEC*
*
2
1
IRQ
1
Bit 0
0
Read:
Write:
Reset:
U
0
*Implemented as an EPROM cell
= Unimplemented
U = Unaffected
Figure 1-1. Option Register (Option)
1. No security feature is absolutely secure. However, Motorola’s strategy is to make reading or
copying the PROM difficult for unauthorized users.
MC68HC705C8A — Rev. 3
MOTOROLA
Technical Data
General Description
For More Information On This Product,
Go to: www.freescale.com
FREESCALE [ Freescale ]
