MattairTech MT-DB--U1, Manual

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MT-DB-U1 Manual
Pin Descriptions
Pin Description
Gnd Ground
5V, Vbus 5V output from USB Vbus. Vbus pin and 5V pin are tied together.
Vcc Voltage input pin. Use solder jumper J8 to configure. This pin is connected
to the Vcc and AVcc pins on the microcontroller, as well as the ISP header
and reset pullup. See Power Configuration Section.
3.3V 3.3V output from the microcontroller internal 3.3V regulator. This pin is
connected to Ucap on the microcontroller.
X2 (C0) This pin can be connected to the XTAL2 pin of the microcontroller using
jumper J7. This is useful if pin C0 is used as GPIO (if external clock is
used). This pin is disconnected by default (onboard crystal is used).
X1 This pin can be connected to the XTAL1 pin of the microcontroller using
jumper J7. This is useful if an external clock is used. This is also useful for
HV programming or recovery from incorrectly set fuses. This pin is
disconnected by default (onboard crystal is used).
C2 GPIO pin (Port C) Consult datasheet for functionality.
D0 ­ D7 GPIO pins (Port D) Consult datasheet for functionality.
D0 / LED The green status LED is connected to this pin when solder jumper J2 is
set. The LED is connected to ground through a 240 ohm resistor. The user
application is free to use this LED. Drive the pin high to turn on the LED.
D7 / HWB This pin is connected to the bootloader jumper (HWB). The jumper is
connected to ground through a 240 ohm resistor. The pin is sampled after
all reset sources, including power­up. If the pin is low (HWB jumper
installed), then the bootloader is run. If the pin is high (HWB jumper
removed), then the user application is run. This pin functions as a normal
GPIO pin at all other times. The 240 ohm resistor provides short­circuit
protection in case the pin is used as an output and the jumper is installed.
RST Connects to reset pin of microcontroller as well as the reset button. A 10K
pullup resistor and 100nF capacitor are connected to this pin. If jumper J1
is set to ISP In, then RST is also connected to pin 5 of the ISP header.
B0 ­ B6 GPIO pins (Port B) Consult datasheet for functionality.
B7 PWM filter C output (OC.1C) or pin B7, depending on jumper
configuration.
C4, C7 GPIO pins (Port C) Consult datasheet for functionality.
C5 PWM filter B output (OC.1B) or pin C5, depending on jumper
configuration.
C6 PWM filter A output (OC.1A) or pin C6, depending on jumper
configuration.
December 30, 2015 9 http://www.mattairtech.com/