UPIO-M3U1XX Datasheet, PDF (6/28 Pages) Silicon Laboratories – The Unified Development Platform (UDP) provides a development

UPIO-M3U1xx
4.2. Switches and LEDs
The I/O card has two push-button switches (SW2 and SW3) and six LEDs (DS1-5 and D1). The switches are
normally open and pull the port pin voltage to ground when pressed. DS5 integrates a red, green and blue LED into
a single component. D1 is a bright white LED. Table 2 shows the port pin connections.
Table 2. Switch and LED Connections
SW or LED
Push-Button Switch (SW2)
Push-Button Switch (SW3)
Red LED (DS1)
Yellow LED (DS2)
Green LED (DS3)
Blue LED (DS4)
Red LED (DS5)
Green LED (DS5)
Blue LED (DS5)
Bright White LED (DS6)
GPIO Pin
PB3.4
PB3.4
PB2.4
PB2.5
PB2.6
PB2.7
PB4.0
PB4.1
PB4.2
PB4.3
4.3. Joystick Switch
The I/O card has five-position joystick switch (SW1). The joystick is normally open and pulls a port pin voltage to
ground when the joystick placed in one of the five positions. Table 3 show the port pin connections to the joystick.
Table 3. Joystick Switch Connections
Joystick Position
Center
Up
Down
Left
Right
GPIO Pin
PB3.3
PB2.13
PB3.0
PB2.14
PB3.1
4.4. Piezo Buzzer
The I/O card has a piezo buzzer (LS1) connected to PB4.4 that resonates audibly when the voltage input is toggled
periodically.
4.5. External Regulator Circuit
The I/O card has a BJT transistor connected to four port pins to implement a regulator circuit with the SiM3U1xx
EXTVREG module. The positive supply to the circuit can be 5 V from the UDP motherboard or PB3.8. PB3.9
connects to the negative supply and the collector of the BJT. The positive and negative supply are used to create a
voltage drop across R42 to regulate the collector current.
PB3.10 is connected to the output of the regulator circuit and the emitter of the BJT. PB3.11 is connected the base
of the BJT and enables and disables the regulator circuit.
4.6. EBID MCU
The I/O card has a unique ID that can be read out from the Silicon Labs C8051F990 MCU (U2). This MCU enables
software tools to recognize the connected hardware and automatically select the appropriate firmware image.
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Rev. 0.1