mc9s12e256 Freescale Semiconductor, Inc, mc9s12e256 Datasheet - Page 578

• Manufacturer Part Number: mc9s12e256
• Description: Hcs12 Microcontrollers 16-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Appendix A Electrical Characteristics
A.4
A.4.1
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 program and erase operations are timed using a clock derived from the oscillator using the
FCLKDIV register. 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.4.1.1
The programming time for single word programming is dependent on the bus frequency as a well as on the
frequency f¨
A.4.1.2
Flash programming where up to 64 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.4.1.3
Erasing a 1024 byte Flash sector takes:
The setup times can be ignored for this operation.
578
Flash NVM
bus
NVM Timing
NVMOP
Single Word Programming
Row Programming
Sector Erase
. The maximum times are calculated for minimum f
and can be calculated according to the following formula.
NVMOSC
is required for performing program or erase operations. The NVM modules
t
t
swpgm
t
bwpgm
MC9S12E256 Data Sheet, Rev. 1.08
brpgm
t
era
=
=
=
9
t
4
swpgm
4000
Table A-14
------------------------ -
f
------------------------ -
f
NVMOP
NVMOP
1
1
------------------------ -
f
NVMOP
+
63 t
1
+
+
25
9
are calculated for maximum f
bwpgm
----------- -
f
----------- -
f
bus
bus
1
NVMOP
1
and a f
bus
Freescale Semiconductor
of 2MHz.
NVMOP
NVMOP
.
and