On this page you will find pictures of the assembled PCB plus important positioning and other information.
Please read the whole page before attempting assembly. Keep scrolling until there’s no more page.
“Top” of the board means where the DB25 connector is. You can tell you’re looking at the top because the “USB” marker for the green dev module is on this side.
“Bottom” of the board means the same side as where the microSD slot goes.
Things which are installed into the bottom side of the PCB:
* Voltage Regulator (three pin device that has a big metal tab with a hole in it)
* R1, and R2. These resistors set the voltage which the regulator outputs. They are different sizes to make identification easier. R2 smaller, R1 larger.
Things which are installed into the top side of the PCB:
* DB25 connector
* Diode
* Fuse
* Termination Resistor Networks (important note on these later in instructions)
* Green dev module / microcontroller module
Here are pictures of the top and bottom with all parts assembled. Note that your kit *does not come with* sockets for the resistor packs, and also does not include a jumper for the Use_Tpwr jumper (it’s hard-soldered). Termination for these is always enabled, and cannot be disabled. Nicer DB25 connectors have been found as well, which come with anchor tabs preinstalled, so you don’t have to bodge something together through the mounting holes.
In these pictures, you will notice that the PCB is labeled with a hardware license and says not for commercial sale. This is because I intend to release the PCB design later on, and it will be a non-commercial license. As the creator of these designs, I am naturally allowed to sell them.
You will note the comments about resistor packs. Each resistor pack has text on one side, and the other side is blank. The side with text has a dot on the left by the letter B (B for Bourns, the manufacturer of the resistor pack). These dots must be in the center, meaning that one resistor pack faces the DB25 connector and the other faces the mirocontroller module. Installing these the wrong way around will cause your unit to not work at all. Picture for reference:
The bottom is pretty straightforward.
The most critical part of the bottom of the PCB is to align the hole in the voltage regulator with the hole in the PCB. A mounting post extends through here to press the metal tab against the exposed metal on the PCB to assist in cooling the voltage regulator.
Note that the leads from the voltage regulator and resistors must be cut short so that the microcontroller module does not touch them. A later revision might move the regulator somewhere else – this is a pretty crowded board.
When installing the case, place the bottom shell on first and ensure that all the alignment holes match up. There’s a post which reaches through to the bottom for extra rigidity, so that will need to line up before the case will fully close.