UM1521
Hardware layout and configuration
Doc ID 022868 Rev 1
11/56
2.3 Clock
source
Two clock sources are available on the STM32L152D-EVAL evaluation board for the
STM32L152ZDT6 and RTC embedded.
●
X1, 8 MHz crystal with socket for the STM32L152ZDT6 microcontroller, it can be
removed from socket when internal RC clock is used.
●
X3, 32 KHz crystal for embedded RTC
2.4 Reset
source
The reset signal of the STM32L152D-EVAL evaluation board is low active and the reset
sources include:
●
Reset button B1
●
Debug tools from JTAG connector CN16 and trace connector CN11
●
Daughterboard from CN10
●
Embedded ST-LINK/V2
●
RS-232 connector CN1 for ISP
Table 4.
8 MHz crystal X1 related solder bridges
Solder bridge
Description
SB1
PH1 is connected to 8 MHz crystal when SB1 is open. (
Default setting
)
PH1 is connected to extension connector CN10 when SB1 is closed. In such case
R51 must be removed to avoid disturbance due to the 8Mhz quartz
SB2
PH0 is connected to 8 MHz crystal when SB2 is open. (
Default setting
)
PH0 is connected to extension connector CN10 when SB2 is closed. In such case
C53 and X1 must be removed.
Table 5.
32 KHz crystal X3 related solder bridges
Solder bridge
Description
SB8
PC14 is connected to 32 KHz crystal when SB8 is open. (
Default setting
)
PC14 is connected to extension connector CN5 when SB8 is closed. In such case
R85 must be removed to avoid disturbance due to the 32Khz quartz
SB7
PC15 is connected to 32 KHz crystal when SB7 is open. (
Default setting
)
PC15 is connected to extension connector CN5 when SB7 is closed. In such case
R84 must be removed to avoid disturbance due to the 32 KHz quartz
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