MattairTech MT-X1, Manual

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MT­X1 Manual
Headers / Pin Descriptions
Pin Description
External Power Header Under the default configuration, 5V should be supplied to this pin. Lower
voltages may be used down to around 4V (or lower if using less current).
Voltages greater than 5.5V require J2 to be disconnected . Disconnecting J2
will disable the 5V output pin and inductive kickback protection of the relay
driver. But it will allow voltages up to ~7.5V. This header is reverse polarity
protected using a schottky diode.
3.3V output headers (x4) There are four 2­pin power output headers next to each port header group. The
header next to the analog ports (ports A and B) comes from the analog 3.3V rail.
Note that if these headers are installed, there will not be enough room to plug in
IDC connectors next to each other.
Relay Header 3.3V This can be used for the positive 3.3V side of a relay or other device.
Relay Header 5V This can be used for the positive 5V side of a relay or other device. This is also
the common cathode of the kickback diodes in the relay driver. Both of these are
disabled when J2 is diconnected.
Relay Header 1­8 These are the 8 relay driver outputs. They are open­drain active low. When
enabled, the output is connected to ground. When disabled, the pin is in a high
impedance state. When driving inductive loads, like relays, free­wheeling diodes
provide kickback protection (when J2 connected). Non­inductive loads can also
be connected (ie: LCD backlight). Each output is capable of sinking 70mA.
Outputs can be combined.
Audio Header This is the singe channel output from the audio amplifier. It can drive 8 ohm
loads. 4 ohm loads may also be connected, but under some conditions,
distortion or automatic thermal shutdown may occur.
JTAG Header JTAG header for the XMEGA which can be used for programming, debugging,
and JTAG boundary scans. Disable JTAG to gain access to the four underlying
analog/GPIO pins.
PDI Header PDI header for the XMEGA which can be used for programming or debugging.
Note that an onboard programmer is already provided. When using this header,
J19 MUST be disconnected.
This is due to the fact that RX and PDI_DATA are
shared. This means that the XMEGA serial TX won't be connected to the USB
AVR RX. This doesn't affect programming, but may present a problem in certain
situations when debugging. If serial TX is required when debugging, the JTAG
header can be used. Alternatively, an external USB­serial bridge can be
connected.
ISP Header ISP header for the USB AVR which can be used for programming or debugging.
The USB AVR can be programmed over USB using the DFU bootloader.
Port A All pins are routed to headers. The 1.25V precision reference can be connected
to pin A0 (Vref input) through a solder jumper. The temperature sensor output
and audio amplifier input are also connected to this port.
June 2, 2015 7 http://www.mattairtech.com/