ST92141 STMicroelectronics, ST92141 Datasheet - Page 73

• Manufacturer Part Number: ST92141
• Description: 8/16-bit Mcu For 3-phase Ac Motor Control
• Manufacturer: STMicroelectronics

5.5 OSCILLATOR CHARACTERISTICS
The on-chip oscillator circuit uses an inverting gate
circuit with tri-state output.
Notes: Owing to the Q factor required, Ceramic
Resonators may not provide a reliable oscillator
source .
OSCOUT must not be directly used to drive exter-
nal circuits.
When the oscillator is stopped, OSCOUT goes
high impedance.
The parallel resistor, R, is disconnected and the
oscillator is disabled, forcing the internal clock,
CLOCK1, to a high level, and OSCOUT to a high
impedance state.
To exit the HALT condition and restart the oscilla-
tor, an external RESET pulse is required.
It should be noted that, if the Watchdog function is
enabled, a HALT instruction will not disable the os-
cillator. This to avoid stopping the Watchdog if a
HALT code is executed in error. When this occurs,
the CPU will be reset when the Watchdog times
out or when an external reset is applied.
Figure 34. Crystal Oscillator
C
*Recommended for oscillator stability
L1
OSCIN
CRYSTAL CLOCK
ST9
1M*
OSCOUT
C
ST92141 - RESET AND CLOCK CONTROL UNIT (RCCU)
L2
VR02116A
Table 17. Crystal Specification (5V)
Legend:
C
and OSCOUT (the value includes the external capaci-
tance tied to the pin CL1 and CL2 plus the parasitic capac-
itance of the board and of the device).
Note: The tables are relative to the fundamental quartz
crystal only (not ceramic resonator).
Figure 35. Internal Oscillator Schematic
Figure 36. External Clock
Rs max
(ohm)
Freq.=
3 MHz
Freq.=
4 MHz
Freq.=
5 MHz
L1
, C
HALT
R
L2
IN
OSCIN
: Maximum Total Capacitances on pins OSCIN
C
L1
56pF
270
150
110
=C
EXTERNAL CLOCK
L2
CLOCK
INPUT
OSCIN
=
C
L1
47pF
350
200
120
ST9
=C
L2
R
OSCOUT
=
NC
C
L1
22pF
850
510
340
=C
OSCOUT
L2
=
R
VR02116B
VR02086A
OUT
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