mc9s12xd256 Freescale Semiconductor, Inc, mc9s12xd256 Datasheet - Page 1087

• Manufacturer Part Number: mc9s12xd256
• Description: Hcs12x Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

then 182 kHz. In this case, the EEPROM program and erase algorithm timings are increased over the
optimum target by:
If the ECLKDIV register is written, the EDIVLD bit is set automatically. If the EDIVLD bit is 0, the
ECLKDIV register has not been written since the last reset. If the ECLKDIV register has not been written
to, the EEPROM command loaded during a command write sequence will not execute and the ACCERR
flag in the ESTAT register will set.
Freescale Semiconductor
Program and erase command execution time will increase proportionally
with the period of EECLK. Because of the impact of clock synchronization
on the accuracy of the functional timings, programming or erasing the
EEPROM memory cannot be performed if the bus clock runs at less than 1
MHz. Programming or erasing the EEPROM memory with EECLK < 150
kHz should be avoided. Setting ECLKDIV to a value such that EECLK <
150 kHz can destroy the EEPROM memory due to overstress. Setting
ECLKDIV to a value such that (1/EECLK+Tbus) < 5 s can result in
incomplete programming or erasure of the EEPROM memory cells.
MC9S12XDP512 Data Sheet, Rev. 2.17
200 182
–
CAUTION
200 100
=
Chapter 26 4 Kbyte EEPROM Module (S12XEETX4KV2)
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