UM1817 Datasheet, PDF (24/58 Pages) STMicroelectronics – Evaluation board with STM32F091VC MCU

Hardware layout and configuration
UM1817
2.18
Note:
IR LED and IR receiver
The IR receiver TSOP34836 is connected to PC6 of the STM32F091VCT6 and a current
around 100 mA on IR LED is driven by PB9 through transistors T4 and T5 on the board.
The IR LED may be driven by PB9 directly with 20 mA current when SB20 is closed and
R116 is removed.
2.19
8x USARTs
USART chain could be routed to a 2*8 header so that some jumpers could be used to
connect them to demonstrate 8x USART channels in daisy chain.The data flow is showed in
the below Figure 8.
Figure 8. USART data flow
U SAR T1_TX
USART2_RX
U SAR T2_TX
U SAR T3_RX
U SAR T3_TX
U SAR T4_RX
U SAR T4_TX
USART5_RX
U SAR T5_TX
USART6_RX
USART6_TX
U SAR T7_RX
U SAR T7_TX
U SAR T8_RX
U SAR T8_TX
U SAR T1_RX
At the end both data sent at USART1_TX and data received at USART_RX can be
compared and validated thanks to USARTs chain on CN1.
Warning:
USART1/4/8 belongs to VDDIO2 power domain and
USART2/3/5/6/7 belongs to VDDIO power domain, so the
same voltage level for VDDIO and VDDIO2 is needed, to
demonstrate USART chain application on this header.
2.20
Display and input devices
The 2.4” color TFT LCD connected to SPI1 port of the STM32F091VCT6 and 4-general-
purpose-color LEDs (LD 1,2,3,4) are available as display device. The 4-direction joystick
(B3) with selection key, which connects to PA0 and supports wakeup feature, and Tamper
button (B2) are also available as input devices (see Table 16).
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