Propeller Education Kit
hacktorious
Posts: 72
Hello,
I got a new Propeller Education kit for Christmas. I'm having several issues and am not sure how to proceed. The first issue is I am not certain where to connect the cathode for the capacitor on the 3.3v supply. I cannot find any info in the book, just the schematic, which I thought I understood. Could someone please give the the coordinates for the capacitors?
Also, I noticed in the testing section it shows several points to test which are actually under the controller. Am I actually supposed to remove the chip to test these points? Thanks.
I got a new Propeller Education kit for Christmas. I'm having several issues and am not sure how to proceed. The first issue is I am not certain where to connect the cathode for the capacitor on the 3.3v supply. I cannot find any info in the book, just the schematic, which I thought I understood. Could someone please give the the coordinates for the capacitors?
Also, I noticed in the testing section it shows several points to test which are actually under the controller. Am I actually supposed to remove the chip to test these points? Thanks.
Comments
I haven't used the PEK but it's common practice to build part of a circuit at a time. They may want you to test the power supplies before plugging the chip into the breadboard.
the PE-Kit Fundamentals write at several places
"Figure 3-5: Wiring Diagram Propeller DIP Plus Kit before ICs are Connected"
Please read the text in order to make sure you do things right.
Can you please post what doc-files you are using?
best regards
Stefan
I am reading the "Propeller Education Kit Labs: fundamentals" by Andy Lindsay, which is what came with the kit. I'm on pages 28-31. Here is the link:
http://parallax.com/sites/default/files/downloads/122-32305-PE-Kit-Labs-Fundamentals-Text-v1.2.pdf
In the diagram (p.27) it shows the anode is connected to the ground (j-6, or j--7 according to the instructions) , and the cathode is connected to the LED side. In the diagram of the board it looks like the reverse. However, my confusion is that I don't quite understand the layout of the board yet. The holes are connected vertically in the diagram, would this mean the anode should be plugged into L-8? The diagram looks opposite or something.
I'm still not sure if I understand everything exactly. So I attach pictures.
If you look on p.26 figure 3-3 you can see how the rows and columms are connected.
On p.27 is the schematic where the anode of the capacitor is connected to +3.3V
and the LEDs anode is connected to +3.3V too.
I attached the breadboard-overview and a cut-out detail
Now look on the detail of the bredboard and the additional text and red line.
The anode of the capacitor must be connected to the row where the red cables are plugged in
(one left from the ground-row)
For building up I recommend plugging in one component and then do a short test.
So this starts with the 9V battery-clip. Pluggin in the battery and measuring the voltage at k1 + and k2 ground
then adding the 5V regulator tripple-checking the right wiring
j1 must be inputpin
j2 must be ground
j3 must be outputpin
connecting your voltmeter to k1 / k2 then connecting the battery and watching the voltage.
If there is a shortcut the voltage would drop down then quickly disconnect battery.
If everything is right check voltage on whole h3 should be 5V
Next step plug in 3.3V regulator
tripple-checking
h3 is input-pin
h4 is ground-pin
h5 is output-pin
again connect battery and measure voltage at k1/k2 if there is no voltage-drop
measure voltage between ground and g5 and l5 should be 3.3V
after that connect wire from l5 to plus-row. then measuring voltage at plus-row
This seems to be a very slow hyper-ultra-careful proceeding. Yes it is. But how long does it take until a new part is purchised and delivered?
And you are right in the picture on p 28 the capacitor connected to plus 3.3V is drawn opposite to the one plugged intothe plus- and ground-row
@Parallax: hacktorious is following the instructions very carefully and found details that make no sense. Please correct it ASAP.
hacktorious The capacitors have a plus or minus identifier on their body. Connect Anode to plus whole k5 and kathode to j6.
Another tip. Do you have a DIP-40 socket?
If yes plug in the Propeller-Chip in the socket. If you remove and re-plug the socket the pins of the prop-chip itself stay connected and
keeps the pins mechanically unloaded.
@Parallax: add a high-precision DIP-40-socket to the kit and rise the price for $1.
As an additional protection I recommend adding 150 Ohm-resistors to ALL 32 IO-Pins.
For 99% of all devices (switches, LEDs, I2C-devices etc) you can connect to the prop-chip this will work properly.
But it adds overcurrent-protection to each IO-Pin.
If you happen to shortcut an IO-Pin to ground while configured as Output-pin and set high to 3.3V the current will be
3.3V / 150 Ohm = 22mA which can be dealt by the IO-Pin without damage. A real shortcut (0,1 Ohm) will blow up the IO-Pin.
best regards
Stefan
In which case I see the anode of the first cap at L-3 and its cathode in the ground rail at position 1. I'm not sure if you've used breadboards with ground and power rails. These are vertically oriented connections instead of horizontally connected strips like those used in the main portion of the breadboard. It might be good to check some of the positions with a meter to make sure it's clear which holes are connected to each other electrically.
I think I just found your confusion. The anode of the first cap looks like it's positioned over the ground rail but there's a black line showing it connected to L-3.
I think the illustration would have been clearer if they had rotated the cap a bit so the anode wasn't directly over the #3 position of the ground rail. The anode kind of looks like a wire from the ground rail to L-3.
The second cap has its anode at k-5 and cathode at j-6.
I hadn't seen you're post #5 before adding post #6.
I think you might be mistaking the position of the 5V cap. The anode is connected to L-3 not the power rail (if that's what you meant by the above description).
Thanks for the diagrams, they were very helpful.
we were posting almost at the same time 8:11 / 8:12 so you had almost no chance to see it.
We both needed some minutes for typing and uploading pictures. So it was a random coincidence.
best regards
Stefan
I was picking up the description of the thread-starter to make it easy to understand.
Now I'm interested: as a real experienced professional how do you call the terminals of a capacitor?
How would you describe a hint like "connect the ...?... of the capacitor to ground" ?
best regards
Stefan
Do you think you don't see the anode/cathode notation since both terminals kind of behave as one or the other depending out whether or not the cap is charging or discharging?
I haven't been involved in electronics as long but I also don't recall this terminology used with capacitors.
I thought the same. Caps have always been + or - ,unless non-polarized.
At least that what Forest Mimms and my 40 year old books tell me.
Is there a new definition of the capacitors leads? (Going to Wiki)
Been there, done that. It didn't help (much). All I could find was a reference to the anode of a battery being dependent on whether it was charging or not. I think the same applies to capacitors (though I'm not sure).
The photo I attached earlier looks like it was taken from Wikipedia but someone added the "anode" and "cathode" captions (I found the modified image with Google).
Duane, I don't think the fact that the positive terminal of a cap could have current flowing into it as well as out of it depending the circuit state should cause confusion since, in either case, the positive terminal is more "positive" than the negative terminal, so the anode and cathode definition would still apply whether the cap is charging or discharging. The current flow change is relative to the circuit, not the cap.