S908AC4MDRE FREESCALE [Freescale Semiconductor, Inc], S908AC4MDRE Datasheet - Page 43

• Manufacturer Part Number: S908AC4MDRE
• Description: M68HC08 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

For EEPROM emulation software to work successfully, the following items must be taken care of in the
user software:
The above EEPROM emulation software can be easily developed by using the on-chip FLASH routines
implemented in the MCU. These routines are located in the ROM memory and support FLASH program
and erase operations. Proper utilization of the on-chip FLASH routines guarantee conformance to the
FLASH specifications.
In the on-chip FLASH programming routine called PRGRNGE, the high-voltage programming time is
enabled for less than 125 µs when programming a single byte at any operating bus frequency between
1.0 MHz and 8.4 MHz. Therefore, even when a row is programmed by 32 separate single-byte
programming operations, t
care of by using this routine.
A page erased operation is provided in the FLASH erase routine called ERARNGE.
Application note AN2635 (On-Chip FLASH Programming Routines) describes how to use these routines.
The following application notes, available at www.freescale.com, describe how EERPOM emulation is
implemented using FLASH:
An EEPROM emulation driver, available at www.freescale.com, has been developed and qualified:
Freescale Semiconductor
1. Each FLASH byte in a page must be programmed only one time until the page is erased.
2. A page must be erased before the FLASH cumulative program HV period (t
3. FLASH row erase and program cycles should not exceed 10,000 cycles, respectively.
maximum t
before the next erase. For more detailed information, refer to
AN2183 — Using FLASH as EEPROM on the MC68HC908GP32
AN2346 — EEPROM Emulation Using FLASH in MC68HC908QY/QT MCUs
AN2690 — Low Frequency EEPROM Emulation on the MC68HC908QY4
AN3040 — M68HC08 EEPROM Emulation Driver
HV
MC68HC908QC16 • MC68HC908QC8 • MC68HC908QC4 Data Sheet, Rev. 5
. t
HV
is defined as the cumulative high-voltage programming time to the same row
HV
is less than the maximum t
HV
. Hence, item 2 listed above is already taken
19.17 Memory
FLASH Memory (FLASH)
HV
Characteristics.
) is beyond the
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