MC912DG128A Motorola, MC912DG128A Datasheet - Page 374

• Manufacturer Part Number: MC912DG128A
• Description: Microcontrollers
• Manufacturer: Motorola

Appendix A: MC68HC912DT128A
1d. Flash
Programming Time
1e. Flash External
Programming
Voltage
2. EEPROM
2a. EEPROM
Architecture
3b. EEPROM Clock
Source and
Pre-scaler
2c. EEPROM AUTO
programming &
erasing
MC68HC912DT128A Rev 2.0
374
The most significant change resulting from the new flash technology is
that the bulk erase and program times are now fixed. The erase time is
at least twice as fast while the word programming time is at least 20%
faster.
The new flash does not require an external high voltage supply. All
voltages required for programming and erase are now generated
internally. Pin 97 that was the VFP pin on the 68HC912DG128 is now a
factory TEST pin. On ealy production devices it is recommended that
this pin is not connected within the application, but it may be connected
to VSS or 5.5V max without issue. On later production parts this pin is
not bonded out.
Like the flash, the EEPROM is also made from this new NVM
technology. The architecture and basic programming and erase
operations are unchanged. However, there is a new optional
programming method that allows faster programming of the EEPROM.
The first major difference on the new EEPROM is that it requires a
constant time base source to ensure secure programming and erase
operations. The clock source that is going to drive the clock divider input
is the external clock input, EXTALi. The divide ratio from this source has
to be set by programming an 10-bit time base pre-scalar into bits spread
over two new registers, EEDIVH and EEDIVL.
The EEDIVH and EEDIVL registers are volatile. However, they are
loaded upon reset by the contents of the non-volatile SHADOW word
much in the same way as the EEPROM module control register
(EEMCR) bits interact with the SHADOW word for configuration control
on the existing revision.
The second major change to the EEPROM is the inclusion in the
EEPROM control register (EEPROG) of an AUTO function using the
previously unused bit 5 of this register.
Appendix A: MC68HC912DT128A
MOTOROLA
2-appA