MT-X1S
Manual
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.
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 USB
serial 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.
Port B
All pins are routed to headers. The 1.25V precision reference can be connected
to pin B0 (Vref input) through a solder jumper. Note that JTAG is connected to
pins B4 – B7. JTAG must be disabled to use these pins for other purposes like
the ADC.
Port C
All pins are routed to headers. No peripheral devices are connected to this port.
Port D
All pins are routed to headers. This port also connects to the LEDs and 32KB
SPI SRAM memory through solder jumpers.
Port E
All pins are routed to headers. This port also connects to the buttons and the
MicroSD card slot through solder jumpers.
Port F
All pins are routed to headers. This port also connects to the USART of the USB
AVR (RX, TX, and optionally, XCK) as well as the SPI inputs of the relay driver
(MOSI and SCK) through solder jumpers. To minimize power consumption. TX
should be tristated before entering sleep.
Ports H, J, and K
All pins are routed to headers. No peripheral devices are connected to these
ports. They can be used for GPIO or for use with external memory.
March 2, 2017
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