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 powerup and reset.
Mode Selection During Powerup 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 MTX1S 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
reversepolarity 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
March 2, 2017
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