Unable to Program Axon, USB not detecting--Help Please!

[saliraza]

Hi,

I have been working with the Axon for quite sometime, just today i tried to update the code and noticed that the USB connection does not establish.

1. Tried troubleshooting the Silab USB-bridge driver yet no luck.
2. Inspected the USB pins for any solder short or loose pins ....all looks fine and continuity good!
3. After disconnecting everything, still the USB does not detected.
4. The 3.3 volt pin shows only 1.6 volts when checked with multimeter.
5. with nothing connected just USB plugged in from PC the SILAB CP2102 IC gets burning hot.
6. Checked the L43 shunt regulator pins almost all three pins had approx 4.xx volts on it.
7. My previous code does work ...however the CP2102 IC gets very hot even without being connected.

Please help as the time this problem started is very bad. In first week of september my Prof. is returning from summer vacations ...I've been working on this project for many months ...everyday till now ....and unable to program my robot. I have to present the demo to my Prof.  :?(  and things really dont look good.

I hope that the above mentioned observations will give you a good insight about what may be the main cause ..... I believe its either the 3.3v supply ....or the CP2102 IC...... I am in desparate need of help....


Regards,

Ali

[SmAsH]

I think that your CP2102 is busted, if the pc doesn't detect anything, it gets very hot and the regulator isn't working.
I'm pretty sure that the CP2102 creates the 3V3 line, so if that isn't working it looks like the chip is gone or faulty.

If you cannot program the axon and really need to, i would suggest getting a hardware programmer.
The other option is to talk to admin about getting a replacement CP2102... but that would require some crazy soldering skills man, trust me!

[Admin]

Yeap, your CP2102 is busted. Were you at any time using the 3.3V line when this happened? Anything you think might have caused this to happen? Changed pin configurations in code? (I just want to know to warn other people to be careful)

Does your CP2102 heat up even when USB is disconnected? If so, there is a permanent short. To 'fix' it, unsolder the 3-pin diode to the left of the chip. Its rectangular, with a pin on top and two on the bottom. This I think will disconnect power to your USB. If it doesn't heat up while USB is disconnected, you can ignore this paragraph.

Anyway, to program without a bootloader, you'll need to buy/borrow a hardware ISP programmer. Mouser/Digikey sells them for ~$36. If you borrowed a programmer, I can write you a bootloader to use on another UART port - you'll just need a serial to USB adapter (under $15).

I have a spare CP2102 that I can mail you, but you'd need a hot air soldering pin and crazy soldering skills (that tiny chip has 28 pins underneath it).

[saliraza]

Thank you Admin and SmAsH,

I have access to a hotair soldering station and can use it as well as get another expert technician to replace the CP2102 on the Axon board. I believe that will fix my problem quicker, the time is critical. I will greatly appreciate if you can mail a CP2102 chip to me, as well as guide me if I can purchase one (or if possible desold one from any hardware you know) from any place that can ship quickly, I live in Ottawa, Canada.

In the mean while I will also check if I can borrow a ISP programmer ..... I have a Microchip PICKit2 programmer....may be that can work, I'll see if it works before asking for a modified bootloader and buying S2U adapter.



Answers to Admin's Questions:

1. Were you at any time using the 3.3V line when this happened?
A. I was powering the bluetooth using the 3.3v (2.2mA to 3.1mA load), I jumped the 3.3v pin on Axon to the beside unused pin (discussed in my previous post) and use that pin to power my bluetooth.

2. Anything you think might have caused this to happen? Changed pin configurations in code?
A. I programmed the device for the last time and test-ran my robot for few minutes. No changes in the code. I cannot think of a major reason that might have caused it, however am thinking about all possibilities since this failure cus i cannot afford any future failures .... The bluetooth kit was placed close to a carbon fiber rod, and it may have shorted out the Vcc and TxD line ..... the bluetooth still works.

3. Does your CP2102 heat up even when USB is disconnected?
A. Withnothing connected to the Axon, even a USB connector .....when I power the Axon the CP2102 heats up. Also when nothing is connected to Axon even no power connections and then i plug in usb cable ...the CP2102 heats up.

If you have any questions please let me know ......

Regards,

Ali

[Admin]

You can buy them here:
http://www.mouser.com/ProductDetail/Silicon-Labs/CP2102-GM/?qs=sGAEpiMZZMtUpMOmSPzkH4LNgvJCyH6m

You may just want to buy a few, just in case. I checked my inventory and only have three left, and I need two of them for prototyping next week. I thought I had more . . . 

I recommend calling up Mouser and asking how long it'll take for them to rush ship it to you. Being in Canada might complicate shipping.

I was powering the bluetooth using the 3.3v (2.2mA to 3.1mA load), I jumped the 3.3v pin on Axon to the beside unused pin (discussed in my previous post) and use that pin to power my bluetooth.

Which bluetooth device? Also, you may need a cap across power and ground:
http://www.societyofrobots.com/axon/axon_FAQ.shtml#usb_voltage
(if the device doesn't do it already)

In the mean while I will also check if I can borrow a ISP programmer ..... I have a Microchip PICKit2 programmer....may be that can work

nope . . .
http://www.mouser.com/ProductDetail/Atmel/ATAVRISP2/?qs=sGAEpiMZZMsaJrqdZ%252b6EWyua%252bG%2fwcOQP26MNKN%252bCIDE%3d
Seems the price dropped to $34!
Programmers are a nice tool to have around, with more features than the Axon bootloader, so don't feel its a waste to buy it. I personally prefer using a programmer.

I have access to a hotair soldering station and can use it as well as get another expert technician to replace the CP2102 on the Axon board

If your tech needs any tips, let me know!

And if you decide to get another Axon, I can FedEx fast (just let me know which shipping type to use).

[saliraza]

Hi Admin,

I have been to the Campus today and checked for my options ......

1. I can get the CP2102 from Digikey (1-2day), however the technicians are aprehensive about damage to the board while removing the old IC and then putting back the good one on. Also the cost of man-hours might exceed the Axon's pricetag.

2. I can buy the ISP programmer ASAP. What i need to know for certain, can I use this programmer for future reprogramming my code to the Axon ...instead of using the bootloader altogether(disconnecting the CP2102 powerpin)??

Please confirm if ISP programmer can get me back to programming the Axon with my code .... and I can leave the usb bootloading option ....

Thank you very much for your prompt support.

Regards,

Ali

[SmAsH]

yes, you can program the board with the hardware programmer, the usb will never be needed again.
and the isp programmer can be used with future avr projects

[Admin]

1. I can get the CP2102 from Digikey (1-2day), however the technicians are aprehensive about damage to the board while removing the old IC and then putting back the good one on. Also the cost of man-hours might exceed the Axon's pricetag.

To remove the chip, I recommend adding some ChipQuick (low temp melting solder paste). If heated properly, the old chip should just slide off. The worst damage you'll do is blacken the PCB. The first time I ever did it, it took me about 40 minutes (and I was definitely no expert at that time).


Anyway, if not the CP2102, I recommend getting a serial to USB adapter as it makes debugging much easier.

[Admin]

What did you end up deciding on/doing?

[saliraza]

Hello,

I have just received the CP2102 IC's from the Digikey. I have also got the AVR ISP programmer. For now, I am going to disconnect the 5v power supply to the CP2102 coming from the L43 shunt voltage reference so that it does not heatup and shortout the supply. I will use the ISP programmer to get my code working on the robot for the presentation. Once that is done then I will ask the technicians help to replace the CP2102 with the new one.

I have one question at this point, after compiling, when I have my Axon.hex file ready, to which memory I should program it ...EEPROM or the flash memory? Sort of a silly question ...and I guess it has to be EEPROM but I just wanna make sure I dont do any further blunder at this point. Also should I expect the AVR programmer to detect the ATMEGA640 itself or I have to specify it?  I remember there was a good tutorial on the forum about this .... I wish I had bookmarked it :?/

At this point I would like to thank from the bottom of my heart all of you who provided me with prompt help and support. I am happy to be a SoR member.

Regards,

Ali.

[Admin]

You have to specify the 640, and program into flash. Make sure the ISP speed is set to 4MHz (in same window as 640 specification).

*DO NOT* change the fuses unless you know what you are doing