XESS XStend XS40, Manual

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Figure 3: Top-side view of the network of VCC and GND buses around the component through-holes
in the XStend Board prototyping area.
The placement of the shunt on jumper J16 will determine whether the VCC buses in the
prototyping area carry either 5V or 3.3V (see Figure 6). Of course, the jumper selection
will have no effect unless you have both these voltages supplied to the XStend Board
either by the XS Board or by connecting external power supplies.
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Figure 4: Shunt placement for setting the VCC bus voltage..
Connections from the XS Board to the prototyping area are made through connector J3.
The arrangement of pins on this connector exactly matches the arrangement of pins on
the XS40 Board. For example, the pin at the bottom-left of J3 on the XStend Board
corresponds to pin 21 at the bottom-left of the XS40 Board.
The XS95 Board has a completely different pin arrangement than the XS40. Therefore,
each pin on J3 is explicitly labeled with the corresponding pin number on the XS95 Board.
For example, the pin at the bottom-left of J3 on the XStend Board is connected to pin 68
near the top-left of the XS95 Board.
Daughterboard Connector
Daughterboards with specialized circuitry can be connected to the XStend board through
connector J18. This 42×2 connector brings all the I/O and VCC/GND from the XS40 or
XS95 Board to the daughterboard.