MC68HC11KA4 MOTOROLA
MC68HC11KA4TS/D 21
3 Erasable Programmable Read-Only Memory
The MC68HC711KA4 has 24 Kbytes of ROM/EPROM. The MC68HC711KA2 has 32 Kbytes of ROM/
EPROM. In all parts, the ROM/EPROM can be mapped to one of two locations in the memory map. The
locations are as follows:
In the MC68HC11KA4, the ROM/EPROM can be mapped at $2000–$7FFF or $A000–$FFFF. If it is
mapped to $A000–$FFFF, vector space is included. In single-chip mode the MC68HC11KA4 ROM/
EPROM is forced to $A000–$FFFF (ROMAD = 1) and enabled (ROMON = 1), regardless of the value
in the CONFIG register.
In the MC68HC11KA2, the ROM/EPROM can be mapped at $0000–$7FFF or $8000–$FFFF. If it is
mapped to $8000–$FFFF, vector space is included. In single-chip mode the MC68HC11KA2 ROM/
EPROM is forced to $8000–$FFFF (ROMAD = 1) and enabled (ROMON = 1), regardless of the value
in the CONFIG register.
In PROG mode, the EPROM/OTPROM is programmed as a stand-alone EPROM by adapting the MCU
footprint to the 27256-type EPROM and using an appropriate EPROM programmer. Programming
EPROM/OTPROM requires an external 12.25 volt nominal power supply (V
PPE
). There are two meth-
ods that can be used to program and verify EPROM/OTPROM.
In normal MCU mode, EPROM/OTPROM can be programmed in any operating mode —special test,
bootstrap, expanded, or single chip. Normal programming is completed using the EPROG register.
To program the EPROM, complete the following steps using the EPROG register:
1. Write to EPROG with the ELAT bit set.
2. Write data to the desired address.
3. Write to EPROG with the ELAT and EPGM bits set.
4. Delay for 10 ms or more, as appropriate.
5. Clear the EPGM bit in EPROG to turn off the V
PPE
voltage.
6. Clear the EPROG register to reconfigure the EPROM address and data buses for normal operation.
MBE — Multiple Byte Program Enable
Used for factory test purposes only
Bit 6 — Not implemented
Always reads zero
ELAT — EPROM Latch Control
If ELAT = 1, EPROM is in programming mode and cannot be read. If ELAT = 1, writes to EPROM cause
address and data to be latched.
0 = EPROM address and data bus configured for normal reads
1 = EPROM address and data bus configured for programming
EXCOL — Select Extra Columns
Used for factory test purposes only
EXROW — Select Extra Row
Used for factory test purposes only
Bits [2:1] — Not implemented
Always read zero
EPROG —EPROM Programming Control $002B
Bit 7 654321Bit 0
MBE — ELAT EXCOL EXROW — — EPGM
RESET: 0000000 0