ST72325R6-AUTO STMicroelectronics, ST72325R6-AUTO Datasheet - Page 48

• Manufacturer Part Number: ST72325R6-AUTO
• Description: 8-bit Mcu For Automotive With 16 To 60 Kbyte Flash, Adc, Css, 5 Timers, Spi, Sci, I2c Interface
• Manufacturer: STMicroelectronics

Supply, reset and clock management
6.3
Caution:
6.4
48/250
Phase locked loop
If the clock frequency input to the PLL is in the range 2 to 4 MHz, the PLL can be used to
multiply the frequency by two to obtain an f
byte. If the PLL is disabled, then f
The PLL is not recommended for applications where timing accuracy is required (see
Section 19.5.6: PLL characteristics on page
Figure 11. PLL block diagram
Multi-oscillator (MO)
The main clock of the ST7 can be generated by three different source types coming from the
multi-oscillator block:
●
●
●
Each oscillator is optimized for a given frequency range in terms of consumption and is
selectable through the option byte. The associated hardware configurations are shown in
Table
External clock source
In this 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 four oscillators with different frequency ranges
has to be done by option byte in order to reduce consumption (refer to
configuration on page 233
multi-oscillator, the resonator and the load capacitors have to be placed as close as possible
to the oscillator pins in order to minimize output distortion and start-up stabilization time.
The loading capacitance values must be adjusted according to the selected oscillator.
These oscillators are not stopped during the RESET phase to avoid losing time in the
oscillator start-up phase.
an external source
4 crystal or ceramic resonator oscillators
an internal high frequency RC oscillator
10. Refer to
Chapter 19: Electrical characteristics
f
OSC
for more details on the frequency ranges). In this mode of the
OSC2
PLL x 2
= f
/ 2
OSC
OSC2
206).
/2.
of 4 to 8 MHz. The PLL is enabled by option
PLL OPTION BIT
for more details.
0
1
f
OSC2
Section 21.1.1: Flash
ST72325xxx-Auto