M68HC11K Datasheet, PDF (101/290 Pages) Freescale Semiconductor, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
Operating Modes and On-Chip Memory
EEPROM and the CONFIG Register
Address: $003F
Bit 7
6
5
4
3
2
1
Bit 0
Read:
ROMAD
1
Write:
CLKX PAREN NOSEC NOCOP ROMON EEON
Reset: —
1
—
—
1
—
—
—
Figure 4-13. System Configuration Register (CONFIG)
NOTE: CONFIG is writable once in normal modes and writable at any time in
special modes.
NOSEC — RAM and EPROM Security Disabled Bit
0 = Enable security
1 = Disable security
M68HC11K Family devices are normally manufactured with NOSEC set
and the security option unavailable. However, on special request, a
mask option is selected during fabrication that enables the security
mode. The secure mode can be invoked on these parts by clearing
NOSEC. Contact a Motorola representative for information on the
availability of this feature.
The bootstrap program performs this sequence when the security
feature is present, enabled, and bootstrap mode is selected:
1. Output $FF, all 1s, on the SCI.
2. Clear the BPROT register by turning block protect off.
3. If the EEPROM is enabled, erase the EEPROM.
4. Verify that the EEPROM is erased. If EEPROM is not erased,
begin sequence again.
5. Write $FF, all 1s, to the entire block of RAM.
6. Erase the CONFIG register.
If all of the operations are successful, the bootload process continues as
if the device was never secured.
M68HC11K Family
MOTOROLA
Operating Modes and On-Chip Memory
For More Information On This Product,
Go to: www.freescale.com
Technical Data
101