UM1521
Hardware layout and configuration
Doc ID 022868 Rev 1
17/56
2.7 Audio
The STM32L152D-EVAL evaluation board supports stereo audio play by using an audio
DAC CS43L22 connected to both I2S2 port and one channel of DAC in the microcontroller
STM32L152ZDT6.
●
OpAmp3 of the STM32L152ZDT6 acts as a low pass filter of audio output for this DAC.
●
A headphone jack is connected to the output of CS43L22.
●
A microphone is connected to ADC through OpAmp1 of STM32L152ZDT6.
The I2C address of CS43L22 is 0b1001010.
The LCD glass module has to be mounted on "IO" position for Audio I2C usage. Refer to
for detail.
2.8 USB
The STM32L152D-EVAL evaluation board supports USB2.0 compliant full speed
communication via a USB type B connector (CN15). The evaluation board can be powered
by this USB connection at 5 V DC with a 500 mA current limitation.
USB disconnection simulation can be implemented by controlling the internal 1.5 K pull-up
resistor on USB+ line and detection of 5 V power on USB connector CN15 by using a
resistor bridge connected to PE6.
USB will work properly when VDD > 3 V.
2.9 RS-232
and
IrDA
RS-232 and IrDA communication is supported by D-type 9-pin RS-232 connector CN1, and
IrDA transceiver U2 which is connected to USART1 of the STM32L152ZDT6 on the
STM32L152D-EVAL evaluation board.
The signals Bootloader_RESET and Bootloader_BOOT0 can be added on RS-232
connector CN1 for ISP support. If Bootloader_RESET signal is used, mount R39 (Default:
Unmounted) with a 0 Ohm resistor as
shows.
Table 13.
Audio related jumpers
Jumper
Description
Setting
JP7
PA4 is connected to analog input signal for ADC or output signal from DAC on
CN8 when JP7 is set as shown to the right:
PA4 output signal to OpAmp3 as low pass filter when JP7 is set as shown to the
right: (
Default setting
)
JP8
Description of JP8 is in
JP6
Description of JP6 is in
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