STMicroelectronics B-G474E-DPOW1, Руководство пользователя

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13.6 RC sinus function
The RC sinus function is used to demonstrate HRTimer output capability.
The principle is to generate a triangle waveform, to show the accuracy of the HRTimer on the ramp down
compared to a standard PWM on the ramp-up. The signal may be filtered with a low-pass filter to get a sine-wave
shape.
The generated signal is available for probing on the TP4 test point.
13.7 Joystick function
The B2 joystick, with 4-direction and a selection key, is located on top. It is used to switch between different
modes of Demonstration Software. It is also used to dim the luminance and select the color of the RGB power
LED. The selection key can be used as a wake-up key. Through their interrupt feature, five PIOs manage this
joystick. All keys are active low.
13.8 Reset button function
The B1 reset button located on top activates the STM32G474RET6 microcontroller PG10-NRST pin (T_NRST
signal tied to GND). It resets the board with a low logical level.
The board reset is also accessible on the CN9 extension connector, on the JP7 header, and on the CN1 debug
connector.
During reset activation, the LD2 blue user LED is lit in low luminance. PA15 has an internal pull-up during reset
and it drives this LD2 with low current.
13.9 Buttons and LEDs function
Table 12 summarizes the different buttons and LEDs of the B-G474E-DPOW1 Discovery kit and their function:
Table 12. Buttons and LEDs
Reference Color Function Comment
B1 Black RESET button (T_NRST) Reset the board
B2 Blue
JOYSTICK_SELECT PC13
JOYSTICK_UP PB10
JOYSTICK_DOWN PC5
JOYSTICK_RIGHT PB2
JOYSTICK_LEFT PC4
LD1 Red, green or blue Lighting
RGB power LED for lighting
application
LD2 Blue LED_DOWN_BLUE
User LED, PA15 (lit during
reset)
LD3 Orange LED_LEFT_ORANGE User LED, PB1
LD4 Green LED_RIGHT_GREEN User LED, PB7
LD5 Red LED_UP_RED User LED, PB5
LD6 Green 3V3 power lit when 3V3 is ON
LD7 Green 5V power lit when 5V is ON
LD8 Red ST-LINK Overcurrent (OC)
lit when STLK overcurrent
detected
LD9 Red, green, or orange ST-LINK COM
lit according to ST-LINK
status
UM2577
RC sinus function
UM2577 - Rev 2
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