• Uses all the features incorporated in the PIC firmware written by Jon Rhees(version 1.7 is required for errorfree operation).

• The PCB is designed to fit in a recuperated COM1 (DB9) + COM2 (DB25) PC bracket and can be mounted in a spare slot inside the PC.
• Takes power from the Wake On Lan connector on the motherboard. If your MB doesn't have this or it's in use already, you can take +5VSB from other locations like the Wake On Modem header.

• It has one input (RBO) wich generates an event to Girder.

• It also has four buffered output ports wich can be controlled by Girder. They can also be controlled by the PIC directly when Girder is not running or even when the PC is powered down: an IR code can be stored in the PIC and the corresponding output can be pulsed, toggled ,set high or low. This is what we use to power up the PC through WOL, WOM or the power button connector. The PC can also be reset by connecting one of these outputs to the reset button.

• LED's or relays can also be connected to these outputs. When doing this and you want to use the 5VSB to power these devices make sure that the PC power supply has enough 5VSB power left. It's better to use another supply like the regular 5 or 12v from the power supply. Also when using inductive loads there needs to be a clamping diode connected over the load to protect the darlington chip.

• The PCB has a stereo jack to connect the IR receiver. There are several types of receivers with jacks already on the market but the connections are different and some use 5V others 12V. I dismantled a Xantech one (for wich I did not have the specs) and it was a 12v one. The +5V pin on the actual receiver had a series resistor of 1K and a zener diode of 5.1V to convert +12 to +5V.

• 2 jacks for IR emitters are provided on the PCB. The values of R5 and R6 need to be determined depending on wich and how many you use. Important: none of the 2 jack connections is ground, so I decided to use a stereo jack and use the pin and ring for the actual connections

• Wake On Lan: The PC can be powered up by using one of the four PIC internal programmable IR codes. WOL requires a positive pulse on it's input so I took a direct PIC I/O pin (RB2) because these are low after reset. Using a buffer transistor would invert this and pull the WOL input high wich might cause problems. A 3k3 series resistor is provided to protect both the PIC and the motherboard in case of incorrect connections. When using WOL the OUT4 output can no longer be used as it uses the same RB2 pin.

• Power up the PC by using the power button. One of the outputs can be used to simulate a power button press. This requires a connection to the "+" of the power button pin on the mother board. Before using this feature verify that the power button shorts it's + pin to ground. Not all motherboards are configured like this and you could damage it.....

• In Circuit Serial Programming: I have succesfully programmed several PIC's using Danjiel Pjitcar's programmer(uirt-dp.prog13), the version on Ruud's site didn't work, his older version wich should work would not open the hex files version 1.6.

If some features are not required the following components can be ommited:

• Wake On Lan: R4 (3K3).
• In Circuit Serial Programming: D1, D2, R7, R9, ZD1 and Shunt1 (solder the 2 pads together). These are also used to reset the PIC when Girder is not running, removing these components will also disable this feature. If you decide to leave them in, bear in mind that the UIRT will not work when Girder isn't running but it will work when the PC is powered off.

• RB0 input: R1, R2 and C1. In this case you must ground the RB0 pin or it could generate false events if left floating.
• Optional emitters: R5 or R6

Construction:

Place all components exept the crystal.

Perform the In Circuit Serial Programming:Place Shunt1 on the top 2 pins and apply the programming voltage (12 - 14v) to the VPP pad.

I used the +12V from an unused hard disk header. 12V is on the low limit for the programming voltage but it has always worked for me, exept once but a second try was succesfull. Another possibility is to "raise" the 5V by connecting a 9V battery to the pins of Shunt1, the minus connects to the +5v pin, the positive to R3. This will create a VPP of 14V.

After programming put shunt1 back on the lowest 2 pins.Mount the crystal and your UIRT2 should be working.