
Operating Modes and On-Chip Memory
Memory Map
MC68HC11E Family
—
Rev. 4
Technical Data
MOTOROLA
Operating Modes and On-Chip Memory
83
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.
Address:
$103C
Bit 7
6
5
4
3
2
1
Bit 0
Read:
RBOOT
(1)
SMOD
(1)
MDA
(1)
IRV(NE)
(1)
PSEL3
PSEL2
PSEL1
PSEL0
Write:
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 4-9. Highest Priority I-Bit Interrupt and Miscellaneous
Register (HPRIO)
Input
Mode
Latched at Reset
MODB
MODA
SMOD
MDA
1
0
Single chip
0
0
1
1
Expanded
0
1
0
0
Bootstrap
1
0
0
1
Special test
1
1