
Technical Data
MC68HC11E Family
—
Rev. 4
86
Operating Modes and On-Chip Memory
MOTOROLA
Operating Modes and On-Chip Memory
4.4.3.1 System Configuration Register
The system configuration register (CONFIG) consists of an EEPROM
byte and static latches that control the startup configuration of the MCU.
The contents of the EEPROM byte are transferred into static working
latches during reset sequences. The operation of the MCU is controlled
directly by these latches and not by CONFIG itself. In normal modes,
changes to CONFIG do not affect operation of the MCU until after the
next reset sequence. When programming, the CONFIG register itself is
accessed. When the CONFIG register is read, the static latches are
accessed. See
4.6.1 EEPROM and CONFIG Programming and
Erasure
for information on modifying CONFIG.
To take full advantage of the MCU
’
s functionality, customers can
program the CONFIG register in bootstrap mode. This can be
accomplished by setting the mode pins to logic 0 and downloading a
small program to internal RAM. For more information, Motorola
application note AN1060 entitled
M68HC11 Bootstrap Mode
has been
included at the back of this document. The downloadable talker will
consist of:
Bulk erase
Byte programming
Communication server
All of this functionality is provided by PCbug11 which can be found on
the Motorola Web site at
http://www.motorola.com/semiconductors/
.
For more information on using PCbug11 to program an E-series device,
Motorola engineering bulletin EB296 entitled
Programming
MC68HC711E9 Devices with PCbug11 and the M68HC11EVBU
has
been included at the back of this document.
NOTE:
The CONFIG register on the 68HC11 is an EEPROM cell and must be
programmed accordingly.
Operation of the CONFIG register in the MC68HC811E2 differs from
other devices in the M68HC11 E series. See
Figure 4-10
and
Figure 4-11
.