ST92196A STMicroelectronics, ST92196A Datasheet - Page 65

• Manufacturer Part Number: ST92196A
• Description: 8/16-bit Mcu For Tv Applications With Up To 96k Rom, On-screen-display And 1 Or 2 Data Slicers
• Manufacturer: STMicroelectronics

5.3 OSCILLATOR CHARACTERISTICS
Because of the real time need of the application, it
is assumed the ST92196A will be used with a 4
MHz crystal fed to the Core by the frequency mul-
tiplier output after it is started and stabilized.
5.3.1 HALT State
When a HALT instruction is processed, it stops the
main crystal oscillator preventing any derived
clock into the chip. Exit from the HALT state can
be obtained through a main system reset.
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 28. Crystal Oscillator
65/268
RESET AND CLOCK CONTROL UNIT (RCCU)
C
*Recommended for oscillator stability
L1
OSCIN
CRYSTAL CLOCK
ST9
1M*
OSCOUT
C
L2
VR02116A
Table 13. Crystal Specification
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 table is relative to the fundamental quartz crys-
tal only (not ceramic resonator).
Figure 29. Internal Oscillator Schematic
Rs max (ohm)
L1
, C
HALT
R
L2
IN
OSCIN
: Maximum Total Capacitances on pins OSCIN
C
1
=C
200
2
=56pF
R
OSCOUT
C
1
=C
260
2
R
VR02086A
=47pF
OUT