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Kova78
August 20th, 2004, 11:41 AM
Hi!
I have modify the UIRT2a scheme (i have deleted from the scheme the line IN and OUT, the WOL connector and ICSP)
The scheme is only used to send and receive IR with girder!
Also I have add the 7805 for the power supply!!
One question: The ground of 7805 power supply must be separated/isoleted from the ground of rs232 pin 5? Can I connect togheter (the ground of 7805 to pin 5 of rs232)?
This is the link for download (right click and save as) http://kova.altervista.org/uirt2a_schemMOD.jpg

The semplify is ok? It will work?

Thanks all and sorry for my eng ;)

danward79
August 20th, 2004, 05:04 PM
Hi,

As the RS232, is not a floating system you may connect the grounds.

Dan

Kova78
August 21st, 2004, 01:49 AM
Hi,

As the RS232, is not a floating system you may connect the grounds.

Dan

Thanks for your answer ;)
Then i can connect GND of 7805 with (together) the GND of rs232, right? I have understand right?
In your opinion the simplification of scheme is correct?
The power supply is enough for the Uirt2?
Have i deleted from the original scheme the right components?

Sorry for all questions :) and sorry for my bad eng :oops:

Bye all :P

danward79
August 21st, 2004, 04:19 AM
Were is the original schematic?

Post a link I will have a look

Dan

Kova78
August 21st, 2004, 06:04 AM
Were is the original schematic?

Post a link I will have a look

Dan

:o :o

It's the uirt2A scheme: http://users.skynet.be/sky50985/uirt2a_schem.pdf

danward79
August 21st, 2004, 06:30 AM
Hi

You need to find out from http://www.microchip.com/, what you should do with unused inputs/outputs. I can't remember if they should be "tied".

I would suggest you leave the provision for in circuit programming in place. This is all the components attached to pin 4. I think the serial input for this is the stuff attached to pin 6. (would need to look at the datasheet to confirm this.)

I would also suggest you install the 100nF cap, on the power rail as close to pin 14 as reasonably possible.

On the input side of the regulator, it may be wise to either use 9 Vdc or lower the 12Vdc, this will reduce the heat produced across the regulator.

What is your reason for removing the 4k7 resistors from the output, and putting in the 10k resistor?

Also why did you remove the RTS signal?

Dan

Kova78
August 21st, 2004, 07:18 AM
[cut]

go here http://users.skynet.be/sky50985/Uirt2a.htm

Circuit simplification:

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.

* DB9 connector, you can solder the wires directly on the pads. If ICSP is not required only GND, RXD and TXD need connection to the comm port.


Thanks for the answer