MC68HC705C9A_1 Datasheet, PDF (37/157 Pages) Freescale Semiconductor, Inc – General Release Specification

2.4 EPROM
Freescale Semiconductor, Inc.
General Release Specification
EPROM
When configured as a C12A the main user EPROM consists of 48 bytes
of page zero EPROM from $0020 to $004F, 12,032 bytes of EPROM
from $1000 to $3EFF, and 14 bytes of user vectors from $3FF4 to
$3FFF. When configured as a C9A, an additional 3,840 bytes of user
EPROM from $0100 to $0FFF are enabled.
Locations $3FF0 and $3FF1 are the mask option registers (MOR) (see
1.5 Mask Options).
For detailed information on programming the EPROM see Appendix A.
EPROM Programming.
2.5 EPROM Security
A security feature has been incorporated into the MC68HC705C9A to
help prevent external access to the contents of the EPROM in any mode
of operation. Once enabled, this feature can be disabled only by
completely erasing the EPROM.
NOTE: For OTP (plastic) packages, once the security feature has been enabled,
it cannot be disabled.
2.6 ROM
The bootloader ROM occupies 239 bytes in the memory space from
$3F00 to $3FEF. The bootloader mode provides for self-programming of
the EPROM array. See Appendix A. EPROM Programming.
2.7 I/O Registers
Except for the option register, mask option registers, and the C12 COP
clear register, all I/O, control and status registers are located within one
32-byte block in page zero of the address space ($0000–$001F). A
summary of these registers is shown in Figure 2-3. More detail about the
contents of these registers is given in two diagrams, each showing a
MC68HC705C9A — Rev. 2.0
Memory
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