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UM1855
Hardware layout and configuration
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2.4 Clock
references
Two clock references are available on STM32L476G-EVAL for the STM32L476ZGT6 target
microcontroller:
•
32.768 kHz crystal X1, for embedded RTC
•
8 MHz crystal X2, for main clock generator
The main clock can also be generated using an internal RC oscillator. The X2 crystal is in a
socket. It can be removed when the internal RC oscillator is used.
2.5 Reset
sources
Reset signal of the STM32L476G-EVAL board is active low.
Table 3. X1-crystal-related solder bridge settings
Solder
bridge
Setting
Description
SB41
Open
Default setting
.
PC14-OSC32_IN terminal is not routed to extension connector CN7. X1 is
used as clock reference.
Closed
PC14-OSC32_IN is routed to extension connector CN7.
R87 must be removed, for X1 quartz circuit not to disturb clock reference
or source on daughterboard.
SB33
Open
Default setting
.
PC15-OSC32_OUT terminal is not routed to extension connector CN7.
X1 is used as clock reference.
Closed
PC15-OSC32_OUT is routed to extension connector CN7.
R88 must be removed, for X1 quartz circuit not to disturb clock reference
on daughterboard.
Table 4. X2-crystal-related solder bridge settings
Solder
bridge
Setting
Configuration
SB24
Open
Default setting
.
PH0-OSC_IN terminal is not routed to extension connector CN7. X2 is
used as clock reference.
Closed
PH0-OSC_IN is routed to extension connector CN7.
X2 and C54 must be removed, in order not to disturb clock reference or
source on daughterboard.
SB23
Open
Default setting
.
PH1-OSC_OUT terminal is not routed to extension connector CN7. X2 is
used as clock reference.
Closed
PH1-OSC_OUT is routed to extension connector CN7.
R95 must be removed, in order not to disturb clock reference or source on
daughterboard.
