UM1537
Hardware layout and configuration
Doc ID 023059 Rev 1
13/52
2.3 Clock
source
Two clock sources are available on the STM320518-EVAL evaluation board for
STM32F051R8T6 and RTC embedded.
●
X1, 8 MHz crystal with a socket for the STM32F051R8T6 microcontroller. It can be
removed from the socket when the internal RC clock is used.
●
X2, 32 kHz crystal for embedded RTC.
2.4 Reset
source
The reset signal of the STM320518-EVAL evaluation board is low active and the reset
sources include the following.
●
Reset button B1
●
Debugging tools from SWD connector CN10 and CN9
●
Daughterboard from CN6
●
Embedded ST-LINK/V2
●
RS232 connector CN7 for ISP.
Note:
The jumper JP6 is to be closed for RESET handled by pin8 of the RS-232 connector CN7
(CTS signal). Refer to
information.
Table 5.
8 MHz crystal X1 related solder bridges
Jumper
Description
SB13
PF0 is connected to an 8 MHz crystal when SB13 is open (default setting).
PF0 is connected to an extension connector CN6 when SB13 is closed. In such a
case, C34 and X1 must be removed.
SB14
PF1 is connected to an 8 MHz crystal when SB14 is open (default setting).
PF1 is connected to an extension connector CN6 when SB14 is closed. In such a
case, R59 must be removed to avoid disturbance due to the 8 MHz quartz.
Table 6.
32 kHz crystal X2 related solder bridges
Jumper
Description
SB9
PC14 is connected to a 32 kHz crystal when SB9 is open (default setting).
PC14 is connected to an extension connector CN5 when SB9 is closed. In such a
case, R57 must be removed to avoid disturbance due to the 32 kHz quartz.
SB10
PC15 is connected to a 32 kHz crystal when SB10 is open (default setting).
PC15 is connected to an extension connector CN5 when SB10 is closed. In such a
case, R58 must be removed to avoid disturbance due to the 32 kHz quartz.
