UM1018
Hardware and layout
Doc ID 18141 Rev 1
11/44
2.7 Audio
The STM32L152-EVAL evaluation board supports both:
●
The speaker which is connected to the DAC output of the STM32L152VBT6 through an
audio amplifier.
●
The microphone which is connected to the ADC input of the STM32L152VBT6 through
a microphone amplifier.
The speaker can be enabled or disabled by setting JP16, refer to
Table 7
for details.
2.8 USB
The STM32L152-EVAL evaluation board supports USB 2.0 compliant full speed
communication via a USB type B connector (CN1). The evaluation board can be powered by
this USB connection at 5 V DC with 500 mA current limitation.
USB disconnection simulation can be implemented by controlling the internal 1.5 K pull-up
resistor on the USB D+ line to detect 5 V power on the USB connector, CN1 (using the
resistor bridge that is connected to PE5).
2.9
RS-232 and IrDA
Both IrDA and RS-232 (with hardware flow control CTS and RTS) communication is
supported by:
●
IrDA transceiver, U17 (connected to USART2 of the STM32L152VBT6 on the
STM32L152-EVAL evaluation board).
●
RS-232 connector, CN2 (D-type 9-pin).
For ISP support, two signals are added on the RS-232 connector CN2:
–
Bootloader_RESET (shared with CTS signal).
–
Bootloader_BOOT0 (shared with DSR signal).
Another RS-232 (without hardware flow control) connector, CN5, is connected to USART3
of the STM32L152VBT6.
Table 7.
Audio related jumpers
Jumper
Description
JP16
Speaker amplifier U27 is enabled when JP16 is open (
default setting
).
Speaker amplifier U27 is disabled when JP16 is closed.
Table 8.
RS-232 and IrDA related jumpers
Jumper
Description
Setting
JP5
USART2_RX is connected to RS-232 transceiver and RS-232 communication
is enabled when JP5 is set as shown (
default setting
).
USART2_RX is connected to IrDA transceiver and IrDA communication is
enabled when JP5 is set as shown.
3
2
1
3
2
1
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