Design own PCB with Serial Port for Roboitic Project

azmax100

Hi all.

I am designing my own PCB for my robotic project. I am planing to include a serial port
for future programming. I used the schematic from parallax (attached below).

My question:

1. Is it I have to connect pin 6 and 7 or 2, 6 and 7. I am a bit confuse with the schematic.

2. What·the different between·Vdd and Vin.

3. Pin 24 on the BS2 have to connect to Vin. If i am using 12v power supply Can i
connect it direct to the pin.


Hope somebody will reply.

Thanks.

---

azmi.

LoopyByteloose

Pin 6 is connected to 7 but NOT to 2.
The schematic is in Eagle software and usually a wire without a Dot is not connected.
If it has a Dot at the intersection, it is connected.

Take a look at the schematics in the Basic Stamp Manual to verify that you are getting the right setup.
Vdd is V+, so is Vcc. In this case, regulated V+ at 5 Volts.


Vss is Ground

Since the BasicStamp has an on-board regulator, Vin is for UNregulated DC and Vdd is for regulated +5.

Regarding the 12v, which BasicStamp are you using?
Some will tolerate +12, but create more heat in the on-board regulator. +9 is better. +7.5 is even better. But often all will work.

If you supply Vin with power, Vdd can be used to output a small current of +5 [noparse][[/noparse]maybe 50ma].

If you supply Vdd with properly regulated power, Vin is useless as the on-board regulator is not operating.

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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········

···················· Tropical regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

azmax100

Thanks Kramer.

I am using BS2.

··· You said:

·· If you supply Vdd with properly regulated power, Vin is useless as the on-board regulator is not operating.

One more question just to make sure. If i connect 7805 output pin to VDD on BS2·is that mean I can just

ignore Vin?

Thanks again.

LoopyByteloose

Yes, I believe so.
But, double check everything for the right voltage at the right places BEFORE you plug in the BS2.

Whenever I build something, I check the Vdd and Vss for all points with actual power on before I populate the board.
Sometimes there is a solder bridge providing power to the wrong place.
Sometimes a reversed capacitor will actually blow up.
And if you use a diode protection scheme [noparse][[/noparse]to discharge large value capacitors] with the 7805, a backwards diode might create a charge pump with +12 volts where you want +5.
These are all things that have happened to me.

Then, I check all the other pins for continuity.

That way, I don't burn up an expensive device by rushing things.
Also, any problems I have later on don't drive me back to doubting my board's construction.

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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········

···················· Tropical regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

azmax100

Thanks Kramer for your help and advice.

Are you using Eagle PCB?

I am using Express PCB for the layout.

I tried to download eagle PCB zip file but after extract the file I only can use the program but not the component library file. How actually to use the library file to get the component on the board?

Here I attached the PCB layout.(using Express PCB)