MC68711E20CFNE3 Datasheet, PDF (45/242 Pages) –

Memory Map
NOSEC — Security Disable Bit
NOSEC is invalid unless the security mask option is specified before the MCU is manufactured. If the
security mask option is omitted NOSEC always reads 1. The enhanced security feature is available in
the MC68S711E9 MCU. The enhancement to the standard security feature protects the EPROM as
well as RAM and EEPROM.
0 = Security enabled
1 = Security disabled
NOCOP — COP System Disable Bit
Refer to Chapter 5 Resets and Interrupts.
1 = COP disabled
0 = COP enabled
ROMON — ROM/EPROM/OTPROM Enable Bit
When this bit is 0, the ROM or EPROM is disabled and that memory space becomes externally
addressed. In single-chip mode, ROMON is forced to 1 to enable ROM/EPROM regardless of the state
of the ROMON bit.
0 = ROM disabled from the memory map
1 = ROM present in the memory map
EEON — EEPROM Enable Bit
When this bit is 0, the EEPROM is disabled and that memory space becomes externally addressed.
0 = EEPROM removed from the memory map
1 = EEPROM present in the memory map
2.3.3.2 RAM and I/O Mapping Register
The internal registers used to control the operation of the MCU can be relocated on 4-Kbyte boundaries
within the memory space with the use of the RAM and I/O mapping register (INIT). This 8-bit
special-purpose register can change the default locations of the RAM and control registers within the
MCU memory map. It can be written only once within the first 64 E-clock cycles after a reset in normal
modes, and then it becomes a read-only register.
Address: $103D
Bit 7
6
5
4
3
2
1
Read:
Write:
Reset:
RAM3
0
RAM2
0
RAM1
0
RAM0
0
REG3
0
REG2
0
REG1
0
Figure 2-12. RAM and I/O Mapping Register (INIT)
Bit 0
REG0
1
RAM[3:0] — RAM Map Position Bits
These four bits, which specify the upper hexadecimal digit of the RAM address, control position of RAM
in the memory map. RAM can be positioned at the beginning of any 4-Kbyte page in the memory map.
It is initialized to address $0000 out of reset. Refer to Table 2-4.
REG[3:0] — 64-Byte Register Block Position
These four bits specify the upper hexadecimal digit of the address for the 64-byte block of internal
registers. The register block, positioned at the beginning of any 4-Kbyte page in the memory map, is
initialized to address $1000 out of reset. Refer to Table 2-5.
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor
45