MC68HC11E0CFNE2 Datasheet, PDF (41/242 Pages) Freescale Semiconductor, Inc – M68HC11 CPU, Power-saving stop and wait modes, Low-voltage devices available (3.0–5.5 Vdc)

Memory Map
Table 2-1. Hardware Mode Select Summary
Input Levels
at Reset
MODB
MODA
1
0
1
1
0
0
0
1
Mode
Single chip
Expanded
Bootstrap
Special test
Control Bits in HPRIO
(Latched at Reset)
RBOOT
SMOD
MDA
0
0
0
0
0
1
1
1
0
0
1
1
A normal mode is selected when MODB is logic 1 during reset. One of three reset vectors is fetched from
address $FFFA–$FFFF, and program execution begins from the address indicated by this vector. If
MODB is logic 0 during reset, the special mode reset vector is fetched from addresses $BFFA–$BFFF,
and software has access to special test features. Refer to Chapter 5 Resets and Interrupts.
Address: $103C
Bit 7
Read: _RBOOT(1)
Write:
6
SMOD⁽¹⁾
5
MDA⁽¹⁾
4
IRV(NE)⁽¹⁾
3
PSEL3
2
PSEL2
1
PSEL1
Bit 0
PSEL0
Resets:
Single chip: 0
0
0
0
0
1
1
0
Expanded: 0
0
1
0
0
1
1
0
Bootstrap: 1
1
0
0
0
1
1
0
Test: 0
1
1
1
0
1
1
0
1. The reset values depend on the mode selected at the RESET pin rising edge.
Figure 2-9. Highest Priority I-Bit Interrupt and Miscellaneous
Register (HPRIO)
RBOOT — Read Bootstrap ROM Bit
Valid only when SMOD is set (bootstrap or special test mode); can be written only in special modes
0 = Bootloader ROM disabled and not in map
1 = Bootloader ROM enabled and in map at $BE00–$BFFF
SMOD and MDA — Special Mode Select and Mode Select A Bits
The initial value of SMOD is the inverse of the logic level present on the MODB pin at the rising edge
of reset. The initial value of MDA equals the logic level present on the MODA pin at the rising edge of
reset. These two bits can be read at any time. They can be written anytime in special modes. MDA can
be written only once in normal modes. SMOD cannot be set once it has been cleared.
Input
MODB MODA
1
0
1
1
Mode
Single chip
Expanded
Latched at Reset
SMOD MDA
0
0
0
1
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor
41