MC68HC912B32MFU8 MOTOROLA [Motorola, Inc], MC68HC912B32MFU8 Datasheet - Page 47

• Manufacturer Part Number: MC68HC912B32MFU8
• Description: 16-Bit Microcontroller
• Manufacturer: MOTOROLA [Motorola, Inc]

8 EEPROM
8.1 EEPROM Programmer’s Model
MC68HC912B32
MC68HC912B32TS/D
The MC68HC912B32 EEPROM serves as a 768-byte nonvolatile memory which can be used for fre-
quently accessed static data or as fast access program code.
The MC68HC912B32 EEPROM is arranged in a 16-bit configuration. The EEPROM array may be read
as either bytes, aligned words or misaligned words. Access times is one bus cycle for byte and aligned
word access and two bus cycles for misaligned word operations.
Programming is by byte or aligned word. Attempts to program or erase misaligned words will fail. Only
the lower byte will be latched and programmed or erased. Programming and erasing of the user EE-
PROM can be done in all operating modes.
Each EEPROM byte or aligned word must be erased before programming. The EEPROM module sup-
ports byte, aligned word, row (32 bytes) or bulk erase, all using the internal charge pump. Bulk erasure
of odd and even rows is also possible in test modes; the erased state is $FF. The EEPROM module
has hardware interlocks which protect stored data from corruption by accidentally enabling the program/
erase voltage. Programming voltage is derived from the internal V
pump. The EEPROM has a minimum program/erase life of 10,000 cycles over the complete operating
temperature range.
The EEPROM module consists of two separately addressable sections. The first is a four-byte memory
mapped control register block used for control, testing and configuration of the EEPROM array. The
second section is the EEPROM array itself.
At reset, the four-byte register section starts at address $00F0 and the EEPROM array is located from
addresses $0D00 to $0FFF (see Figure 9). For information on remapping the register block and EE-
PROM address space, refer to 5 Operating Modes and Resource Mapping.
Read access to the memory array section can be enabled or disabled by the EEON control bit in the
INITEE register. This feature allows the access of memory mapped resources that have lower priority
than the EEPROM memory array. EEPROM control registers can be accessed and EEPROM locations
may be programmed or erased regardless of the state of EEON.
Using the normal EEPROG control, it is possible to continue program/erase operations during WAIT.
For lowest power consumption during WAIT, stop program/erase by turning off EEPGM.
If the STOP mode is entered during programming or erasing, program/erase voltage will be automati-
cally turned off and the RC clock (if enabled) is stopped. However, the EEPGM control bit will remain
set. When STOP mode is terminated, the program/erase voltage will be automatically turned back on if
EEPGM is set.
At bus frequencies below 1 MHz, the RC clock must be turned on for program/erase.
DD
supply with an internal charge
MOTOROLA
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