ST7232AK2-Auto STMicroelectronics, ST7232AK2-Auto Datasheet - Page 37

• Manufacturer Part Number: ST7232AK2-Auto
• Description: 8-bit MCU for automotive, 16 Kbyte Flash, 10-bit ADC, 4 timers, SPI, SCI
• Manufacturer: STMicroelectronics

Specifications of ST7232AK2-Auto

• Hdflash Endurance: 100 cycles, data retention
• Clock Sources: crystal/ceramic resonator oscillators and bypass for external clock
• Four Power Saving Modes: halt, active halt, wait and slow
• Main Clock Controller With: real time base, beep and clock-out capabilities
• Two 16-bit Timers With: 2 input captures, 2 output compares, PWM and pulse generator modes

ST7232Axx-Auto
Figure 10. Clock, reset and supply block diagram
6.4
Caution:
6.4.1
6.4.2
RESET
OSC2
OSC1
V
V
DD
SS
Multi-oscillator (MO)
The main clock of the ST7 can be generated by two 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
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
f
unsafe/undefined state. The product behaviour must therefore be considered undefined
when the OSC pins are left unconnected.
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 4 oscillators with different frequency ranges
has to be done by option byte in order to reduce consumption (refer to
devices on page 185
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.
OSC
An external source
4 crystal or ceramic resonator oscillators
clock frequency in excess of the allowed maximum (> 16MHz), putting the ST7 in an
7. Refer to
Reset sequence manager
Multi-oscillator
(MO)
(RSM)
Section 12: Electrical characteristics
f
for more details on the frequency ranges). In this mode of the multi-
OSC
(option)
PLL
SICSR
0
System integrity management
Supply, reset and clock management
0
for more details.
0
0
WDG
f
RF
OSC2
Main clock controller
with real-time clock
Section 14.2: Flash
Watchdog timer
(MCC/RTC)
(WDG)
f
37/201
CPU