st72324bk STMicroelectronics, st72324bk Datasheet - Page 26

• Manufacturer Part Number: st72324bk
• Description: 3 V/5 V Range 8-bit Mcu With 4/8 Kbyte Rom, 10-bit Adc, Four Timers And Spi
• Manufacturer: STMicroelectronics

Supply, reset and clock management
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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 4 oscillators with different frequency ranges
has to be done by option byte in order to reduce consumption (refer to
153
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.
Internal RC oscillator
This oscillator allows a low cost solution for the main clock of the ST7 using only an internal
resistor and capacitor. Internal RC oscillator mode has the drawback of a lower frequency
accuracy and should not be used in applications that require accurate timing.
In this mode, the two oscillator pins have to be tied to ground.
Table 4.
External clock
Crystal/ceramic resonators
Internal RC oscillator
for more details on the frequency ranges). In this mode of the multioscillator, the
Clock sources
ST7 clock sources
Hardware configuration
C
L1
EXTERNAL
SOURCE
OSC1
OSC1
OSC1
CAPACITORS
LOAD
ST7
ST7
ST7
OSC2
OSC2
OSC2
Section 13.1 on page
C
ST72323 ST72323L
L2