Hi!
I'm using SM5100D 3.3V shield with netduino. I am not using it directly on top of netduino, but it is connected via wires. ND+ is powered with 9V via connector.
If I connect ND+ 5V pin to 5V pin on a cellular shield, it does not work (I get just some gibberish on a serial interface). But if I connect 5V pin from ND+ to VIN pin on cellular shield, the shield starts working. This is somewhat unexpected, since if I put it on top of ND+, VIN from ND+ would become VIN on cellular shield, and that does not work, since VIN is much higher than 5V (9+ V in my case) and I tried that as well, and it does not work. I was afraid for a second that I might have damaged the cellular shield, but it is still working.
What am I doing wrong?
Regards,
Miha.
Powering SM5100 with ND+
Started by Miha, Oct 20 2011 11:46 AM
3 replies to this topic
#2
Stefan W.
-
- Members
-
- 153 posts
Advanced Member
Posted 20 October 2011 - 03:34 PM
The Vin pin on the shield goes to a voltage regulator, that outputs ~3.8V, while the 5V and 3.3V pins are not connected on the shield. So you *have* to power it via vin. It's a low-drop regulator, so it's normal that it works with 5V (as Vin would be 5V also when the (net/ar)duino are powered via usb. However, it should also work fine if you connect +9V to it ...
http://www.sparkfun.... shield-v12.pdf shows you which pins are connected (top right of the schematics).
I believe that no discovery of fact, however trivial, can be wholly useless to the race, and that no trumpeting of falsehood, however virtuous in intent, can be anything but vicious.
-- H.L. Mencken, "What I Believe"
-- H.L. Mencken, "What I Believe"
#3
Mario Vernari
-
- Members
-
- 1768 posts
Advanced Member
- LocationVenezia, Italia
Posted 20 October 2011 - 06:00 PM
Nothing related to the problem itself, but if is involving the Netduino Plus it's better to file the thread under the proper category.
Cheers
Biggest fault of Netduino? It runs by electricity.
#4
Miha
-
- Members
-
- 94 posts
Advanced Member
Posted 20 October 2011 - 08:10 PM
The Vin pin on the shield goes to a voltage regulator, that outputs ~3.8V, while the 5V and 3.3V pins are not connected on the shield. So you *have* to power it via vin. It's a low-drop regulator, so it's normal that it works with 5V (as Vin would be 5V also when the (net/ar)duino are powered via usb. However, it should also work fine if you connect +9V to it ...
Thank you for the explanation.
http://www.sparkfun.... shield-v12.pdf shows you which pins are connected (top right of the schematics).
Cool. I found out that I needed to connect rx/tx to pins 2 and 3 by trying, as I didnt understand this schematic. I don't have any jumpers on the board that I could move around... and I didn't really understand the UART positioning. Can you explain the UART part to me please, so I can understand it (hopefully) in the future schematics? Thanks.
Edit: on second thought, while reexamining the schematic and the breakout board, I guess the jumpers are "things" that looke like small SMD stuff near D pins? And by removing solder and applying it differently, I can change which RX/TX is the real RX/TX... Not important for me really, but I think I understand. It is just that I expected a jumper to be similar to a jumper seen in 286 and 386 computers, where you had pins sticking out, and you put this plastic cap on top of two pins...
) (Re: Mario: I know, but I figured this part is probably the same, and since ND forum is a bit more frequent that ND+ forum, I hoped to get a faster answer here
. Thanks for the heads up, though.Regards,
Miha.
0 user(s) are reading this topic
0 members, 0 guests, 0 anonymous users
