Datasheet

MT-X1S Manual
Buttons / Jumper
There are four modes of operation which are selected using the PROG button and JMP
jumper. The button and jumper are sampled when powering up or pressing reset. Additionally, the MT-
X1S can be switched between the AVRISP mkII programmer and the serial bridge during runtime by
pressing the PROG button. This is useful, for example, to program the XMEGA, then switch to the
serial bridge for printf() debugging. The reset button resets the USB AVR, which will in turn reset the
XMEGA when it boots. The following table lists the mode selection during power-up and reset.
Mode Selection During Power-up and Reset
PROG Button JMP Jumper Mode
Pressed Installed DFU Bootloader
Not Pressed Installed Configuration Mode
Pressed Not Installed AVRISP mkII PDI Programmer
Not Pressed Not Installed USB Serial Bridge
Power / Status LEDs
There are two green LEDs that are used to indicate USB status, the mode of operation,
communication activity, programmer status, and more. The following table lists LED functionality in
each mode. Both LEDs are turned off in sleep mode.
LED Functionality
Mode STS LED PWR LED
AVRISP mkII Programmer Programmer Activity PWM pulsing
Configuration Mode On On
USB Serial Bridge RX Activity TX Activity
DFU Bootloader On Off
Power Supply
The MT-X1S can be powered via USB or via an external header. Both sources are connected
to the input of a 1A, 3.3V LDO linear regulator through Schottky diodes rated at 2A each (2A was
chosen also to keep the dropout voltage low throughout the range of current). The diodes provide
reverse-polarity protection as well as ensuring that current will not flow from one source to the other.
For example, if the external header has a greater voltage than the USB VBUS voltage, the diode
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