MT-X1S
Manual
J28
Serial TX (pin E3) to RS232 DIN or RS485 DI (external pullup)
J29
Serial Noninverting screwterminal to 680 ohm bias resistor to 3.3V (RS485 ONLY)
J30
Serial Nonnverting screwterminal to 120 ohm termination resistor to Inverting screw
terminal (RS485 ONLY)
J31
Serial Inverting screwterminal to 680 ohm bias resistor to GND (RS485 ONLY)
J32
3.3V to 33KOhm minimum current resistor to GND (MTX1S ONLY) Disconnect for
lowest power consumption, but observe 3.3V regulator minimum load specification
J33
Jumpers J33 and J34 allow routing of the USB data lines to either the XMEGA or the
A90USB162. Jumpers J10 and J11 were changed to 3pad to support this. The Serial
RAM cannot be used when the XMEGA is connected to USB. See Board Variants
section above.
J34
See J33
J35
J35 connects the STS_LED to TX (XMEGA F2) . This allows the XMEGA to control the
STS LED when the AT90USB162 in not installed. See Board Variants section above.
J36
J36 connects the PROG button to XCK (XMEGA F1) . This enables bootloader entry
selection for the DFU bootloader on the XMEGA when the AT90USB162 in not installed.
See Board Variants section above.
J37
The XMEGA reset line is also the PDI_CLK line used for programming/debugging. It
cannot have a capacitor installed. J37 disconnects the debouncing capacitor of the Reset
button for use with the XMEGA . See Board Variants section above.
J38
J38 connects Reset button to XMEGA PDI_CLK (also reset). This allows the XMEGA to
be reset when the AT90USB162 in not installed. See Board Variants section above.
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 then allow voltages up to ~7.5V. This header is reverse
polarity / reverse current 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.
March 2, 2017
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