3.4 Peripherals
The EFR32FG23 Dev Kit contains a set of peripherals that can be accessed from the EFR32FG23:
• One segment LCD
• One Silicon Labs Si7021 relative humidity & temperature sensor
• One LC sensor
• One LED and two push buttons
3.4.1 Segment LCD
A 20-pin segment LCD is connected to the EFR32FG23's LCD peripheral. The LCD has 4 common lines and 10 segment lines, giving a
total of 40 segments. These lines are not shared on the breakout pads. Refer to the kit schematic for information on signals to seg-
ments mapping.
4x10 Segment LCD
EFR32FG23
PD[5:2]
LCD_SEG[19:18]
PC[9:8]
LCD_SEG[10,8]
PA[4,0]
PC[1:0]
LCD_SEG[1:0]
PC[7:4]
LCD_SEG[7:4]
LCD_COM[4:0]
LCD_SEG
LCD_COM
PA6
LCD_CP
1 uF
Figure 3.3. Segment LCD
3.4.2 Si7021 Relative Humidity and Temperature Sensor
The Si7021 I
2
C relative humidity and temperature sensor is a monolithic CMOS IC integrating humidity and temperature sensor ele-
ments, an analog-to-digital converter, signal processing, calibration data, and an I
2
C interface. The patented use of industry-standard,
low-K polymeric dielectrics for sensing humidity enables the construction of low-power, monolithic CMOS Sensor ICs with low drift and
hysteresis, and excellent long term stability. The Si7021 offers an accurate, low-power, factory-calibrated digital solution ideal for meas-
uring humidity, dew-point, and temperature, in applications ranging from HVAC/R and asset tracking to industrial and consumer plat-
forms.
Si7021
Temperature
& Humidity
Sensor
VMCU
EFR32FG23
PA08
PA07
I2C_SCL
I2C_SDA
Figure 3.4. Si7021 Relative Humidity and Temperature Sensor
Although measures have been taken to thermally isolate the sensor from the board, temperature readings will be influenced when pow-
er is dissipated on the board. More accurate temperature measurements are achieved when powering the board with a battery or
through the Mini Simplicity connector as self-heating from the on-board LDO is eliminated and the on-board debugger is put in a low
power state.
UG508: EFR32FG23 Dev Kit User's Guide
Hardware
silabs.com
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