How can I tell if my chip is dead?
tjaeger
Posts: 5
I have the same problem and board/chip as described in this thread:
http://forums.parallaxinc.com/forums/default.aspx?f=25&m=438829
The board lights up red and blue when I plug in the USB, the green power light is one, VDD on the chip is correct (3.3V), VDD on the EEPROM is correct, my device manager on my PC is detecting the USB cable, and the chip was working before today. However, if I try to verify hardware or load a program to the EEPROM with the Propeller Tool I get the "No propeller chip found on any serial port" error, and the program that was already loaded doesn't do anything anymore. I also have another board with the same program on it that is fully functioning.
Is there a definitive way to tell if the chip is broken? Or maybe there are some other suggestions I can try.
Thanks,
Troy
http://forums.parallaxinc.com/forums/default.aspx?f=25&m=438829
The board lights up red and blue when I plug in the USB, the green power light is one, VDD on the chip is correct (3.3V), VDD on the EEPROM is correct, my device manager on my PC is detecting the USB cable, and the chip was working before today. However, if I try to verify hardware or load a program to the EEPROM with the Propeller Tool I get the "No propeller chip found on any serial port" error, and the program that was already loaded doesn't do anything anymore. I also have another board with the same program on it that is fully functioning.
Is there a definitive way to tell if the chip is broken? Or maybe there are some other suggestions I can try.
Thanks,
Troy
Comments
Were there any bits of metal on the table you set the board down onto that could cause a short?
You could use the other working and visually compare the differences between it and the bad board
I've had problems with computer to Propeller communications that were all the computer's fault.
Edit: My problem had to do with the way ports were assigned. Some of my boards would work while others wouldn't.
If you have a Prop Plug, you could try bypassing the FTDI chip and connect directly to pins 30,31, RST, and GND and see if it will identify.
But, I'd guess your Prop is dead
Let's get back to basics first.
What board are you using? (ie. Parallax Proto USB? Gadget Gangster Propeller USB?, something else?). There are lots of different Propeller boards out there. Knowing which one can give you more targetted advise on what to do.
Is it USB or Serial connection to the board?
Where did you get it from? (ie. Bought it new from Parallax, new from Gadget Gangster, second hand from eBay, etc). Will help us with some basic assumptions on what may be happening.
Has it ever worked? (did it work in the past? or have you just started?, or have you tried to fix something that was known to be broken?)
What is it's history? (If known. For example, a friend used it, never worked for him, he tried to repair it, didn't work, gave it to you, now you are looking at it... etc).
What have you done with it since you had it? (Any details will help. ie, this was a kit, you followed the instructions and put it together (don't laugh, but I've seen someone use hobby glue instead of solder as they didn't know what they were doing - beautiful work - just no electrical connections between components).
What happened before it failed? (ie. Connected a large solinoid directly to it and drove it via PWM with different frequencies till the solinoid threw and arc. (BTW. Don't do this, this would likely kill your poor Propeller chip)).
I've got a couple of USB Propeller boards, three I built from scratch etching the boards and soldering in the components, etc. And I've bought some blank Propeller USB boards from Gadget Gangster that I've built and given to friends. All of them have exhibited the problem of "no propeller found on any comm port" and there have been various solutions needed to get them working. Normally just bad solder joints, however I've also seen a bad USB cable, and a bad Crystal, though I've NEVER seen a bad Propeller chip. I'll share my troubleshooting, but I can speed up the troubleshooting for you based on the answers above questions.
Basic troubleshooting.
You will need)
Documentation.
http://www.parallax.com/ProductInfo/Microcontrollers/PropellerGeneralInformation/PropellerMediaPage/tabid/832/Default.aspx
http://www.alldatasheet.com/
A) User/owner guide for the board.
C) Pin out of the Propeller Chip on the board (found in the Propeller manual)
D) Pin out of the USB chip, ie. if it's an FT232RL then you'll need the pin-out.
Tools you'll need.
A) Multi-meter that can measure voltage and resistence. You can buy a cheap one at a dollar shop for about $10.
C) Depending on your dexterity, you may want to put together a Pin on the end of a pencil or pen with a wire to a crocodile clip. You can then use this to measure the voltages on very small pins (ie. QFP prop or FT232RL USB chip).
D) You may need a soldering iron, probably a 15W with a small tip, rosen core solder, rosen desolder wick and possibly some wire wrap wire.
E) Consider a magnifying glass. My eyesight it shot from years of work on electronics and sitting in front of computer screens 16 hours of the day. I also use a little barrel lense out of an old scanner, wonderful for checking between the FT232RL pins.
1) Check the details in the documentation. If for example it says it needs +9V with center pin positive, then we will need that.
2) Check your supply against the documentation. (see above)
3) Test your supply. (DC side not AC mains side) Make sure it's the correct voltage before plugging it into the board. Verify that it's the correct orientation, ie. center pin positive. If your using a battery, check that it's not flat.
4) Plug it in and observe if any power lights come on.
If there are no lights, then
4A) Measure the voltage on the connector from the supply, if there is no voltage then this is the place to start looking.
4B) If the connector works ok, then measure at the input of the regulator (if no voltage then it's something between the regulator and the power supply connector, start measuring. If there is a switch in between then check the voltage coming in and going out.
4C) Measure the output pin of the regulator and see if your getting it's voltage (ie. a 7805 will put out +5V), and then the 3.3V regulator.
4D) Make sure the 3.3V gets to the Propeller Chip power pins (there are more than one depending on the package).
If you are getting the right voltages to the right places then proceed to 5.
5) USB testing. Plug in the cable, If the board has any activity LEDs on the USB chip (ie. FT232 RL) then these may actually flicker (normal). You should see Windows identify a USB Serial adapter.
5A) If windows sees an unknown device, then go to Control Pannel, SYSTEM, HARDWARE, DEVICE MANAGER, USB devices). If it's there but unknown then follow the steps to apply the FTDI driver. http://www.parallax.com/tabid/530/Default.aspx
5B) Using the Propeller Tool try the "F7" to "Identify Hardware". You should see it try the comm ports, if it sees the USB comm port then great. if not check the FTDI driver, and maybe try a reboot (that's fixed it for me in the past!).
5C) If it's still not found then check the USB connection. Disconnect the cable from the PC, leave the cable in the Propeller board. Check the pin in the cable (PC side fo the cable) to the corresponding pins on the USB chip (see chip pin-out and circuit diagram of the board). You will need to put your multimeter in Resistence mode or Continuity mode. If you do not see a connection then it could be;
5Ci) A bad USB cable (unlikely)
5Cii) Bad solder joints, usually;
- uUSB connector solder joint to the board.
- USB chip (ie. FT232RL) pin on the board.
- or a bad (cracked circuit board track) (very rare, but I've seen it)
After resolving the connection problem then retest the USB connection.
5D) If it's still not working then check the electrical continuity between pins on the FT232RL compared to the pin-out and the circuit diagram for shorts (solder bridges) again use the multi-meter in resistence or continuity mode.
5E) Check pin to pin electrical connections. This will isolate out the solder joints and board. This can be tedious, if you find a bad solder joint then fix it.
If this doesn't work then go to 6.
6) Reconnect and use the Logic Probe (my friend (I usually start here, but the basics help)). Connect the logic probe to the board circuit ground and the +5V supply.
6A) Put it on the USB recieve line (check board circuit diagram and chip pin out). Then do the "F7" you should see a pulse (LED flicker) on the Logic probe, this indicates that it's tried to identify the chip.
6Ai) if it doesn't then keep the Logic probe connected, disconnect the USB cable from the PC side, wait a few minutes (or a reboot of the PC), reconnect and see if the PC tries to talk to the USB chip. If it doesn't then you'll have a USB cable, PC Driver, USB port issue.
6B) If you saw the flicker on the Recieve line, then look at the USB chip output to the Propeller Chip P31. This should momentarily flicker on the F7.
6C) If that all works, then you should check the Prop Reset Line, normally high. On F7 it should be taken LOW for a short period. You can read in the Propeller manual the actual details of what it's doing. You can measure this with the Logic Probe, it this is not happening then check the circuit between the Prop and the USB chip, normally it's the DTR line on the chip, toggles the base of a transistor, which pulls the floating (or pulled high) Propeller pin to ground (LOW) and back up. You should be able to test this on the USB chip (see the circuit diagram and pin out), and then the base of the transistor and then the Prop Pin. If you don't see this occur then it's where you should start troubleshooting.
6Ci) I've had this issue too many times, usually it's the USB chip not soldered properly and not operating correctly.
6D) If you are recieving from the USB, and the Prop chip is then resetting, then check that Pin 30 of the Prop Chip answers back, through the USB chip (follow the circuit diagram) then to the USB connector. This may be an itterative process using the F7.
When all of Step 6. is resolved then you should be able to see the Propeller chip identified in the Propeller tool.
7) Try loading a basic LED flash demo program into memory. Use the Logic Probe to test.
If that works then;
8) Try loading it into EEPROM. if that doesn't work then troubleshoot the EEPROM circuit and connections.
9) Try loading the Graphics DEMO, with output to a composite TV. Your logic probe should give you enough information to guess if this is working without connecting a monitor or RCA port on a TV, but a it's a cool demonstration if it's working.
If it doesn't then this is where I've seen bad Crystal experiences. In one case I soldered it too low and bridged between the pin and the can (crystal case). I've also seen a "dead" crystal.
10) if all of this works then write a program to walk the pins (on and off), check with the logic probe to ensure all pins are good.
Try to answer the above, we'll see what we can do to help. Please be open with any details (ie. you plugged in a 50V power supply in reverse (center pin negative), or you bought it broken,etc) This will help us to help you.
In the past in this forum I've seen folks with these issues and it's been they've used a dead +9V battery, dead power supply, etc. If it was bought new and good, you should try and use the warranty from the seller before taking a soldering iron to the board (you'll void the warranty).
Don't get frustrated. Treat this as a learning experience.
Dave
I'm not sure it this will work, but try using a resistor in series with an LED as a probe. About ~1K will do. Just a normal LED that will use a few MA of current. Connect the cathode of the LED to ground, connect a wire to the resistor (maybe a bit of wire wrap wire (something small that you can position easily (make sure it's insulated)). Again a Pin, on the end of a pen may work as the tool. And try that on the Reset line. It's a short pulse, it may see it, I've never tried it. But it could be quicker than the logic probe.
If that doesn't show the reset then, then start back tracking to the line on the FT232RL (or whatever USB chip it is) (from memory it's the DTR line, but I'd need to look. I think it's LOW most of the time and pulsed HIGH, you should catch this flicker with the LED. If you see that, then you sould see that on the Base of the transistor, etc. Following the circuit diagram will help.
If you don't see it on the FT232RL or whatever the USB chip is, then it maybe that the USB chip is in some funny state, so check the rest of it's pins, such as the reset and test lines.
If you don't have a circuit diagram, then let us know what the board is in case one of us can further guide you.