HT45FM03B Datasheet, PDF (60/83 Pages) Holtek Semiconductor Inc – Brushless DC Motor Flash Type 8-Bit MCU

HT45FM03B
Register
ADCR
ACSR
CMPC
MISC
OPAC
DBTC
Reset
(Power-on)
WDT Time-out
RES Reset
(Normal Operation) Normal Operation
RES Reset
(HALT)
0100 0000 0100 0000 0100 0000 0100 0000
---- -000 ---- -000 ---- -000 ---- -000
1011 0000 1011 0000 1011 0000 1011 0000
000x 0--- 000x 0--- 000x 0--- 000x 0---
0000 0000 0000 0000 0000 0000 0000 0000
-000 0000 -000 0000 -000 0000 -000 0000
Note:
²u² stands for unchanged
²x² stands for unknown
²-² stands for unimplemented
WDT Time-out
(HALT)*
uuuu uuuu
---- -uuu
uuuu uuuu
uuuu u---
uuuu uuuu
-uuu uuuu
Oscillator
Various oscillator options offer the user a wide range of
functions according to their various application require-
ments. Three types of system clocks can be selected
while various clock source options for the Watchdog
Timer are provided for maximum flexibility. All oscillator
options are selected through the configuration options.
More information regarding the oscillator is located in
Application Note HA0075E on the Holtek website.
Clock Source Modes
There are three methods of generating the system
clock, using an external crystal/ceramic oscillator, an
external RC network and an internal RC clock source.
One of these three methods must be selected using the
configuration options.
· _{External Crystal/Ceramic Oscillator}
The simple connection of a crystal across OSC1 and
OSC2 will create the necessary phase shift and feed-
back for oscillation. However, for some crystals and
most resonator types, to ensure oscillation and accu-
rate frequency generation, it is necessary to add two
small value external capacitors, C1 and C2. The exact
values of C1 and C2 should be selected in consulta-
tion with the crystal or resonator manufacturer¢s spec-
ification.
C1
O SC1
In te r n a l
O s c illa to r
C ir c u it
Rp
Rf
Crystal Oscillator C1 and C2 Values
Crystal Frequency
C1
C2
12MHz
8pF
10pF
8MHz
8pF
10pF
4MHz
8pF
10pF
1MHz
100pF
100pF
Note: C1 and C2 values are for guidance only.
Crystal Recommended Capacitor Values
· _{External RC Oscillator}
Using the external system RC oscillator requires that
a resistor, with a value between 47kW and 1.5MW, is
connected between OSC1 and VDD, and a capacitor
is connected to ground. Although this is a cost effec-
tive oscillator configuration, the oscillation frequency
can vary with VDD, temperature and process varia-
tions and is therefore not suitable for applications
where timing is critical or where accurate oscillator fre-
quencies are required. Note that only the OSC1 pin is
used, which is shared with I/O pin PD2, leaving pin
PD3 free for use as a normal I/O pin.
V DD
R O SC
470pF
O SC1
T o in te r n a l
C2
O SC2
c ir c u its
N o te : 1 . R p is n o r m a lly n o t r e q u ir e d . C 1 a n d C 2 a r e r e q u ir e d .
2 . A lth o u g h n o t s h o w n O S C 1 /O S C 2 p in s h a v e a p a r a s itic
c a p a c ita n c e o f a r o u n d 7 p F .
Crystal/Resonator Oscillator - HXT
PD3
External RC Oscillator
Rev. 1.00
60
December 16, 2009