Hardware layout and configuration
UM1817
18/58
DocID026902 Rev 3
2.7 Audio
STM32091C-EVAL evaluation board supports stereo audio playback and microphone
recording by an external headset connected on audio jack CN13. Audio play is connected to
DAC output of the STM32F091VCT6 through an audio amplifier and microphone on
headset is connected to ADC input of the STM32F091VCT6 through a microphone
amplifier. Audio amplifier is enabled or disabled by setting JP17 and mono/stereo playback
is selected by setting JP14, refer to
for details.
Audio amplifier operates correctly when VDDA > 2.2V and microphone amplifier operates
correctly when VDDA > 2.7V.
2.8
RS-232, RS-485 and IrDA
The RS-232 (with hardware flow control CTS and RTS), the RS-485 and the IrDA
communication are supported by the D-type 9-pins RS-232/RS-485 connectors CN9, and
by the IrDA transceiver U14 which is connected to the USART1 of the STM32F091VCT6 on
the STM32091C-EVAL evaluation board. The signal Bootloader_RESET (shared with CTS
signal) and the Bootloader_BOOT0 (shared with DSR signal) are added on the RS-232
connector CN9 for ISP support.
USART1_Rx is chosen by setting of JP13, refer to
for details.
Table 8. Boot0 related jumpers
Jumper
Description
JP4
The Bootloader_BOOT0 is managed by pin 6 of the connector CN9 (RS-232 DSR
signal) when JP4 is closed. This configuration is used for the bootloader application
only.
Default Setting: Not fitted
Table 9. Audio related jumpers
Jumper
Description
JP17
Speaker amplifier U18 is enabled when JP17 is closed (Default setting)
Speaker amplifier U18 is disabled when JP17 is open
JP14
Mono playback is enabled when JP14 is set as shown to the right (Default setting):
Stereo playback is enabled when JP14 is set as shown to the right:
1 2 3
1 2 3
