Changes compared to version 3.42:

• optional crystal, only needs to be used for outdoor-applications or if you got one of these uncalibrated LPCs
• 10-pinhead for LEDs, makes it even possible to connect push-buttons, e.g. for relais-actor
• R12 and R18 are now 3k3, for use with the dimmer R13 and R14 are obsolete

Changes compared to version 3.31:

• an improved transmitter design

• an inductor as input filter

• programming pushbutton and LED onboard

• an external pcb for the status LEDs

The new transmitter now works with a well defined level of approx. -7V. It's independent of the actual bus situation. High bus load needs a significant higher current for the same level compared to a low bus load. This is due to the fact that EIB components pull less current during a logical zero compared to normal operation. Therefore the transmitter needs to compensate this current to get the same dI at the choke. The maximum current is limited to approx. 350mA by the FET.

The inductor maintains a minimum current of approx. 3mA during the reception of a logical zero from the bus. The previous version didn't pull any curent in this case and would have stressed the concerned transmitter more. In addition the filter effect is most welcome.

The programing pushbutton on the controller board makes it much easier when the board is laying in front of you on the table. It also gives more space on the application boards for more important things. But it's also possible to leave the pushbutton on the application board.

The separate pcb for the status LEDs allows everyone to chosse his own layout. Some like to place all 8 LEDs horizontaly, others prefer 2 x 4 vertical ... you only need a tiny pcb.

The schematic: (in Firefox: right click to view a bigger image)

Assembling:

Pay attention to mount the puschbutton, the LED and the 10-pinhead on the soldering side. If th pushbutton is not used you need to bridge the inner 2 contacts in case you have a single sided pcb. (GND)

Optionaly you can mount athe crystal (7,3728MHz) and C7/C8. In that case you need to specify in flash-magic that you are using an external crystal. If not the LPC is still running with the internal RS-oscillator. This is done in the Flash-Magic menu under ISP and then Device Configuration. there you have to select High Speed Crystal.

For normal operation a jumper needs to be placed over pin1 (Vout) and pin2 (Vin) of the ISP connector.

The schematic and the layout can be found in the Download-Area. Professiolal PCBs can be ordered in our shop. Be aware that we only order if there is sufficient interest. So, be perpared that it may take a while.

There is also a  Reichelt-orderlist and below a part list with links. (thx mel)

Have fun
Andreas (kubi)