MattairTech MT--D21E, Руководство пользователя, Страница: 10 / 39

MT-D21E User Guide
A16, A17 (I2C) These can be used for digital functions. Additionally, jumpers J8 and J9
can be enabled, which will connect two 4.7Kohm pullup resistors for use
with I2C.
A18, A19, A22, A23 These can be used for digital functions.
A27 / Button A This can be used for digital functions. By default, this pin is connected to
Button A through jumper J13. This button is debounced using a 249ohm
resistor and a 100nF capacitor. The pin is brought to ground when the
button is pressed. The button is used for bootloader entry (optional) or can
be for general purpose use.
A28 / LED This can be used for digital functions. By default, this pin is connected to a
blue LED through jumper J14 and a 499ohm resistor. The LED circuit
should consume around 1mA. Drive the pin high to turn on the LED.
A30 / SWD CLK This can be used for digital functions. Additionally, this pin is connected to
the Cortex debug header where it is used as SWD CLK.
A31 / Button B / SWD
IO
This can be used for digital functions. Additionally, the pin is routed to the
Cortex debug header where it is used as SWD IO. Alternatively, this pin
can be connected to Button B through jumper J15 (note that this button
can also be used for RST). This button is debounced using a 249ohm
resistor and a 100nF capacitor. The pin is brought to ground when the
button is pressed. The button can be can be for general purpose use.
RST
RST connects to the reset pin of the microcontroller, to Button B through
jumper J15 ( note that this button can also be for general purpose use; see
A31 above), and to the Cortex debug header. A 10K pullup resistor is
connected as well.
NC These pins are not connected to anything. There are 7 pins marked NC.
Cortex Debug Header This 10­pin, 50­mil header can be connected to an external
programmer/debugger.
July 11, 2016 10 http://www.mattairtech.com/