Rc Sinus Function; Joystick Function; Reset Button Function; Buttons And Leds Function - STMicroelectronics B-G474E-DPOW1 Manual

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:
Reference
B1
B2
LD1
LD2
LD3
LD4
LD5
LD6
LD7
LD8
LD9
UM2577 - Rev 2
Table 12. Buttons and LEDs
Color Function
Black RESET button (T_NRST)
JOYSTICK_SELECT
JOYSTICK_UP
Blue JOYSTICK_DOWN
JOYSTICK_RIGHT
JOYSTICK_LEFT
Red, green or blue Lighting
Blue LED_DOWN_BLUE
Orange LED_LEFT_ORANGE
Green LED_RIGHT_GREEN
Red LED_UP_RED
Green 3V3 power
Green 5V power
Red ST-LINK Overcurrent (OC)
Red, green, or orange ST-LINK COM
UM2577
RC sinus function
Comment
Reset the board
PC13
PB10
PC5
PB2
PC4
RGB power LED for lighting
application
User LED, PA15 (lit during
reset)
User LED, PB1
User LED, PB7
User LED, PB5
lit when 3V3 is ON
lit when 5V is ON
lit when STLK overcurrent
detected
lit according to ST-LINK
status
page 32/54