mc9s12hz256v2 Freescale Semiconductor, Inc, mc9s12hz256v2 Datasheet - Page 636

• Manufacturer Part Number: mc9s12hz256v2
• Description: Hcs12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Appendix A Electrical Characteristics
A.3
A.3.1
The time base for all NVM program or erase operations is derived from the oscillator. A minimum
oscillator frequency f
do not have any means to monitor the frequency and will not prevent program or erase operation at
frequencies above or below the specified minimum. Attempting to program or erase the NVM modules at
a lower frequency a full program or erase transition is not assured.
The Flash and EEPROM program and erase operations are timed using a clock derived from the oscillator
using the FCLKDIV and ECLKDIV registers respectively. The frequency of this clock must be set within
the limits specified as f
The minimum program and erase times shown in
maximum f
A.3.1.1
The programming time for single word programming is dependant on the bus frequency as a well as on the
frequency f
A.3.1.2
Flash programming where up to 32 words in a row can be programmed consecutively by keeping the
command pipeline filled. The time to program a consecutive word can be calculated as:
The time to program a whole row is:
Row programming is more than 2 times faster than single word programming.
A.3.1.3
Erasing a 512 byte Flash sector or a 4 byte EEPROM sector takes:
636
t
t
t
brpgm
era
swpgm
4000
t
NVM, Flash and EEPROM
=
bwpgm
NVMOP
bus
=
NVM timing
t
Single Word Programming
Row Programming
Sector Erase
. The maximum times are calculated for minimum f
swpgm
9
Unless otherwise noted the abbreviation NVM (Non Volatile Memory) is
used for both Flash and EEPROM.
---------------------
f
NVMOP
---------------------
f
and can be calculated according to the following formula.
NVMOP
=
NVMOSC
1
NVMOP
1
+
4
31 t
---------------------
f
NVMOP
.
is required for performing program or erase operations. The NVM modules
+
1
bwpgm
25
MC9S12HZ256 Data Sheet, Rev. 2.05
----------
f
bus
+
1
9
----------
f
bus
1
NOTE
Table A-11
are calculated for maximum f
NVMOP
and a f
bus
Freescale Semiconductor
of 2MHz.
NVMOP
and