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Operating Modes and On-Chip Memory
Data Sheet
M68HC11E Family — Rev. 5
48
Operating Modes and On-Chip Memory
MOTOROLA
2.3.3.1 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
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
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
on using PCbug11 to program an E-series device, Motorola engineering bulletin
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
Address: $103F
Bit 7
654321
Bit 0
Read:
NOSEC
NOCOP
ROMON
EEON
Write:
Resets:
Single chip:
Bootstrap:
Expanded:
Test:
0
U
1
U
U(L)
U
U(L)
1
U
= Unimplemented
U indicates a previously programmed bit. U(L) indicates that the bit resets to the logic level held in the latch prior to reset,
but the function of COP is controlled by the DISR bit in TEST1 register.
Figure 2-10. System Configuration Register (CONFIG)