ST72361J4-AUTO View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
ST72361J4-AUTO
STMicroelectronics
ST72361J4-AUTO Datasheet PDF : 279 Pages
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Supply, reset and clock management
ST72361xx-Auto
Figure 11. Clock, reset and supply block diagram
OSC2
OSC1
RESET
/ 8000
8-BIT TIMER
MULTI-
OSCILLATOR
(MO)
fOSC
fOSC2
PLL
(option)
SYSTEM INTEGRITY MANAGEMENT
MAIN CLOCK
CONTROLLER
WITH REALTIME
CLOCK (MCC/RTC)
fCPU
RESET SEQUENCE
MANAGER
(RSM)
AVD Interrupt Request
SICSR
0
AVD AVD LVD
IE F RF
0
0
0
WDG
RF
WATCHDOG
TIMER (WDG)
LOW VOLTAGE
VSS
DETECTOR
VDD
(LVD)
AUXILIARY VOLTAGE
DETECTOR
(AVD)
5.4
Multi-oscillator (MO)
Caution:
The main clock of the ST7 can be generated by two different source types coming from the
multi-oscillator block:
● an external source
● a crystal or ceramic resonator oscillator
Each oscillator is optimized for a given frequency range in terms of consumption and is
selectable through the option byte. The associated hardware configuration are shown in
Table 8. Refer to the electrical characteristics section for more details.
The OSC1 and/or OSC2 pins must not be left unconnected. For the purposes of Failure
Mode and Effect Analysis, it should be noted that if the OSC1 and/or OSC2 pins are left
unconnected, the ST7 main oscillator may start and, in this configuration, could generate an
fOSC clock frequency in excess of the allowed maximum (> 16 MHz), putting the ST7 in an
unsafe/undefined state. The product behavior must therefore be considered undefined when
the OSC pins are left unconnected.
External clock source
In external clock mode, a clock signal (square, sinus or triangle) with ~50% duty cycle has to
drive the OSC1 pin while the OSC2 pin is tied to ground.
Crystal/ceramic oscillators
This family of oscillators has the advantage of producing a very accurate rate on the main
clock of the ST7. The selection within a list of five oscillators with different frequency ranges
must be done by option byte in order to reduce consumption (refer to Section 22.2.1: Flash
configuration for more details on the frequency ranges). The resonator and the load
capacitors must be placed as close as possible to the oscillator pins in order to minimize
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Doc ID 12468 Rev 3
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