Can I have fried my propeller?
Silinary
Posts: 4
Hello all, new to the forums here and well, microcontrollers in general. Playing around with a BS2 boe-bot, but with a side project picked up a Propeller Project Board USB. I was just trying to figure out basic servo controls and the propeller stopped being detected by SimpleIDE, or the spin programming environment. Apologies but at work atm so I dont' have the tools in front of me atm and memory isn't the best.
Basic question really, is can a MG90S servo that is stalled pull too much amperage through the data pin to fry the propeller or connecting circuitry? My setup is fairly simple, I only soldered a 40pin header to the quickstart section. I had the data pin (orange) going to pin 16, and power and ground going to an external power supply, with a ground wire connected from the external supply strait to the propeller's quickstart header GND pin. I used a small breadboard if it matters. I have not yet tried a different computer or USB port, will try that later today.
After testing one servo, I started working on a second one and while it was trying to push past 0 degrees because I havn't figured out the exact C code for working with the servos yet, the servo stopped trying to push. Going through the programming tools indicate it can not find the propeller on any com port. I realize in hindsight I should have put a resistor on the data pin to ensure to protect the microcontroller, but that is now water under the bridge. I'm now wondering if I did indeed fry the microcontroller, or if there is something else that happens to be at play that is a known issue that I havn't found in all my searches.
I do have the right drivers and everything worked fine for about a week before this test. I believe the computer sees the device as an unknown USB device on COM5. Com5 shows as an active choice, but trying to send a program or use identify in the propeller spin program yields no propeller found. I can update this more when I can get home and look at the computer again.
Thank you for any assistance.
Basic question really, is can a MG90S servo that is stalled pull too much amperage through the data pin to fry the propeller or connecting circuitry? My setup is fairly simple, I only soldered a 40pin header to the quickstart section. I had the data pin (orange) going to pin 16, and power and ground going to an external power supply, with a ground wire connected from the external supply strait to the propeller's quickstart header GND pin. I used a small breadboard if it matters. I have not yet tried a different computer or USB port, will try that later today.
After testing one servo, I started working on a second one and while it was trying to push past 0 degrees because I havn't figured out the exact C code for working with the servos yet, the servo stopped trying to push. Going through the programming tools indicate it can not find the propeller on any com port. I realize in hindsight I should have put a resistor on the data pin to ensure to protect the microcontroller, but that is now water under the bridge. I'm now wondering if I did indeed fry the microcontroller, or if there is something else that happens to be at play that is a known issue that I havn't found in all my searches.
I do have the right drivers and everything worked fine for about a week before this test. I believe the computer sees the device as an unknown USB device on COM5. Com5 shows as an active choice, but trying to send a program or use identify in the propeller spin program yields no propeller found. I can update this more when I can get home and look at the computer again.
Thank you for any assistance.
Comments
I don't think it should be a problem with the Project board but sometimes, I have to press the reset button on the QuickStart half of a second before pressing F10 or F11. Apparently a debug signal from the Prop can interfere with the download process. I kind of doubt this is your problem though.
The servo signal shouldn't kill the Prop. I rarely use resistors on my servo projects and I have a lot of projects which use servos. I didn't use any resistors when making my 32 servo demo nor do I use resistors with my 18 servo hexapod.
Smarter people than myself suggest using resistors with servos so it's probably a good idea. One reason I don't use resistors is I've found some servos will not respond to 3.3V logic if a resistor is in line with servo. I'm sure a lower value resistor probably won't cause this issue and it would probably be a good idea to use some sort of resistor.
Let us know when you are back at your computer so we can suggest other things to try.
On this particular issue, no. The signal pin is only supplying a signal. There is really no current involved, (minimal). The real current is being pulled from the power and and ground lines.
Hal, sorry I should have mentioned that yes, the green power light is on. Now that I am home and at my computer and board, I see that when plugged in, it is recognized in Devices and printers (win 7) as FT232X USB UART. LOAD VCP is enabled in it's advanced settings and everything in that respect seems to work. When I try to identify it using the propeller tool, the red RX led lights up for a split second and then the error comes in saying it wasn't found.
I tried setting it up on my laptop, but it got the same problem (though on com7)
I hooked up an LED to the 3.3v and GND pins, and it came on. That with the power light should say it's getting power just fine.
I tried using the reset button multiple times, I do have to I say I dont' like the reset button on this board as it felt mushy and took a bit of effort to make it 'click' to where I felt it was fully depressed. That said, I see no result after pressing the reset pin. The program that was on it was:
/*
Blank Simple Project.c
http://learn.parallax.com/propeller-c-tutorials
*/
#include "simpletools.h" // Include simple tools
#include "servo.h"
int main() // Main function
{
// Add startup code here.
while(1)
{
// Add main loop code here.
servo_angle(16, 140); // P16 servo to 0 degrees
pause(3000);
}
}
I tried connecting the LED to pin 16 and resetting it, as well as unplugging and plugging it in, but no result could be seen.
Hold the reset button down, and get a reading on all the pins. They cannot be connected to anything.
In reset all legs should be floating, this means you should be able to pull each leg high or low with a simple 10k resistor.
If any leg doesn't float to high or low when you hook up a 10 k to the leg while the prop is in reset, you have an issue.
If a prop is fried, chances are even the reset will not function properly, and might show random legs on the prop being actively pulled high or low by the prop, I have had a few props do this also when they die. They hold legs high or low permanently, even when not hooked up to an eeprom. Either the prop will get hot, or you will see legs that are permanently high or low, and cannot be pulled opposite with a 10k.
Any properly floating leg when in reset or when not running a program, can easily be pulled high or low.
Put your finger on the propeller chip after you have had the power on for a few minutes, is it warm/hot to the touch?
CAREFULL IT COULD BURN YOU, IF ITS COOKIN!
Do any other parts on the board get warm/hot to the touch?
Do you see any obviously burn traces, solder bridges, damaged traces... etc...
Take a picture of your setup, so people can see how you have everything wired up.
Inspect all solder joints on the board, perhaps you have a pcb with a bad solder joint that didn't act up at first.
Almost every propeller I fried, started to get warm/hot after it was popped.
The best way to test a prop for failure, is measure the resistance between positive 3.3v and ground, while the board is completely off and discharged.
There are other components on the pcb, but if the prop is fried, you should measure very low resistance between 3.3v and ground, not all props fry like this, by the majority I have tested after they died, showed abnormal resistance readings over positive and negative.
If someone else has the same circuit board, they could test the resistance between positive and negative, and let you know what a working board is supposed to read.
Make sure all resistance tests are done with a blank pcb (nothing plugged in and no parts on the prototyping area) (or at least disconnect all parts from VSS and VDD before testing resistance)
Good luck.
I have an email to tech support, but seeing as this is a $24 board, I think I'm going to just chalk this one up to a learning experience and get a new board. Maybe the quickstart this time so I don't need to solder hehe.
Thank you all for the help and suggestions.
You might want to double check that you have the latest version of the Prop Tool.
If you are doing smt soldering, get a precision temp solder gun, with detachable gun.
Once you buy a nice one, you never buy another one. (you just buy packs of tips for $5 each tip)
They last much longer than average guns/tips also.
$222
http://www.amazon.com/Pace-Analog-Solder-Station-Housing/dp/B00FS77LL6/ref=sr_1_3?s=power-hand-tools&ie=UTF8&qid=1393906437&sr=1-3
Im sure you are being modest.. if it worked at one point....