The 512 bytes of EEPROM is located at $0800–$09FF, and can be programmed or erased without an additional external high voltage supply which has provide great benefit for Clone Motorola MM908E621A Eeprom Data. The program and erase operations are enabled through the use of an internal charge pump. For each byte of EEPROM, the write/erase endurance is 10,000 cycles.
The 8-bit EEPROM non-volatile register (EENVR) and the 16-bit EEPROM timebase divider non-volatile register (EEDIVNVR) contain the default settings for the following EEPROM configurations:
EENVR and EEDIVNVR are non-volatile, EEPROM registers. They are programmed and erased in the same way as EEPROM bytes in order to Unlock Philip Microcontroller P87C750 Eeprom Data. The contents of these registers are loaded into their respective volatile registers during a MCU reset. The values in these read/write, volatile registers define the EEPROM configurations.
For EENVR, the corresponding volatile register is the EEPROM array configuration register (EEACR).
For the EEDIVNVR (two 8-bit registers: EEDIVHNVR and EEDIVLNVR), the corresponding volatile register is the EEPROM timebase divider register (EEDIV: EEDIVH and EEDIVL)
A 35ms timebase is required by the EEPROM control circuit for program and erase of EEPROM content. This timebase is derived from dividing the CGMXCLK or bus clock (selected by EEDIVCLK bit in CONFIG2 register) using a timebase divider circuit to faciliate the process of Motorola MC68HC908JK8 Embedded Flash Memory Restoration, controlled by the 16-bit EEPROM timebase divider register (EEDIVH and EEDIVL) from COPY Microcontroller.
As the CGMXCLK or bus clock is user selected, the EEPROM timebase divider register must be configured with the appropriate value to obtain the 35ms. The timebase divider is calculated using the following formula:
EEDIV = INT [Reference frequency (Hz) ´ 35 ´ 10–6 + 0.5]