HC705C9AGRSSLASHD datasheet(37/157 Pages) NXP

37 / 157 page

General Release Specification

EPROM

MC68HC705C9A — Rev. 2.0

Memory

2.4 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

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

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