MC68HC705C9A Datasheet, PDF (28/118 Pages) Motorola, Inc – Microcontrollers

Memory
2.4 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.
2.5 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.
2.6 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 Figure 2-4.
MC68HC05C9A Advance Information Data Sheet, Rev. 4.1
28
Freescale Semiconductor