XC912BC32CFU8 Motorola Semiconductor Products, XC912BC32CFU8 Datasheet - Page 346

• Manufacturer Part Number: XC912BC32CFU8
• Description: M68HC12B Family Data Sheet
• Manufacturer: Motorola Semiconductor Products

Electrical Specifications
19.13 Pulse-Width Modulator Characteristics
Data Sheet
346
E-clock frequency
A-clock frequency
B-clock frequency
Left-aligned PWM frequency
Left-aligned PWM resolution
Center-aligned PWM frequency
Center-aligned PWM resolution
1. V
Selectable
Selectable
8-bit
16-bit
8-bit
16-bit
DD
= 5.0 Vdc ± 10%, V
When checking to ensure that the reservoir capacitance value of C4 is not too low,
the voltage level of V
Remember that the largest current draw on erasing is when all of the bits of the
FLASH are programmed to 0. Conversely, the highest programming current is
seen when programming all the bits to 0 from the erased state of 1. The user should
look at this on an oscilloscope, due to the brevity of the pulses. Using a port pin or
the SHDN signal may be useful to trigger the scope when the pulses are fired. If
the voltage dips below 11.4 volts, the capacitance used can be increased, but be
sure to verify that decay rates of V
with each successive pulse, try inserting some delays between each pulse to allow
the charge pump to recharge.
The solution shown here uses the ST662A dc-dc converter, but any similar device
will work. Some other options are the LTC1262C from Linear Technology
Corporation or the MAX662 from Maxim Integrated Products, Inc.
Characteristic
SS
= 0 Vdc, T
A
(1)
= T
L
to T
Electrical Specifications
H
FP
, unless otherwise noted
can be monitored during an initial erase and a write pulse.
DD
and V
Symbol
f
r
f
r
f
f
f
CPWM
CPWM
LPWM
LPWM
ECLK
ACLK
BCLK
FP
are still the same. If V
f
f
ECLK
ECLK
f
f
f
f
f
f
ECLK
ECLK
ECLK
ECLK
ECLK
ECLK
Min
—
/256 M
/512 M
/128
/128
/1 M
/2 M
/4 K
/4 K
M68HC12B Family — Rev. 8.0
f
f
ECLK
ECLK
f
f
f
f
f
f
Max
ECLK
ECLK
ECLK
ECLK
ECLK
ECLK
8.0
FP
/2
/2
is declining
MOTOROLA
MHz
Unit
Hz
Hz
Hz
Hz
Hz
Hz