Clock References; Reset Source; Table 6. 32 Khz Crystal X2 Related Solder Bridges; Table 7. 8 Mhz Crystal X3 Related Solder Bridges - STMicroelectronics STM32G081B-EVAL User Manual

UM2403
6.3

Clock references

Two clock sources are available on STM32G081B-EVAL Evaluation board for
STM32G081RBT6 and RTC embedded.
•
X2, 32KHz Crystal for embedded RTC
•
X3, 8MHz Crystal for the STM32G081RBT6 microcontroller, it can be disconnected by
removing R45 and R46 when internal RC clock is used
Jumper
PC14 is connected to 32KHz crystal when SB18 is open (default setting).
SB18
PC14 is connected to extension connector CN9 when SB18 is closed. In such case R43 must be
removed to avoid disturbance due to the 32Khz quartz.
PC15 is connected to 32KHz crystal when SB19 is open (default setting).
SB19
PC15 is connected to extension connector CN9 when SB19 is closed. In such case R44 must be
removed to avoid disturbance due to the 32Khz quartz.
Jumper
PF0 is connected to 8MHz crystal when SB20 is open (default setting).
SB20
PF0 is connected to extension connector CN10 when SB20 is closed. In such case R45 must be
removed to avoid disturbance due to the 8Mhz quartz.
PF1 is connected to 8MHz crystal when SB21 is open (default setting).
SB21
PF1 is connected to extension connector CN10 when SB21 is closed. In such case R46 must be
removed to avoid disturbance due to the 8Mhz quartz.
6.4

Reset source

The general reset of the STM32G081B-EVAL Evaluation board is active low and the reset
sources include:
•
Reset button B1
•
Debugging Tools from SWD connector CN12 and CN13
•
Daughterboard from CN4
•
Embedded ST-LINK/V2-1
•
RS232 connector CN11 for ISP.
Note: The jumper JP12 to be closed for RESET handled by pin8 of RS232 connector CN11 (CTS
signal), please refer to

Table 6. 32 KHz crystal X2 related solder bridges

Table 7. 8 MHz crystal X3 related solder bridges

Section 6.6.2
UM2403 Rev 2
Hardware layout and configuration
Description
Description
for detail.
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