Propeller chip stopped working, can anyone tell me why?
woody363
Posts: 7
In the middle of a project the propeller chip/propstick simply stopped working, flashed its lights briefly and no longer draws power.
After receiving the "propeller education kit" and setting up the initial circuit I found that the 5V regulator didnt work, with a 9V battery input across "P+" and "0" terminal, there was also 9V across the "5" and "0" pins. Since i had a nice expensive power supply that could produce a very reliable 5V I removed the regulator and connected the power supply up instead. I'm reasonably sure that this isn't the cause of the problem, but I could be wrong.
Setting up the initial testing circuits showed no problems, they all functioned fully.
My next circuit was a very rudimentary stepper motor control, see attachment for breadboard layout. The setup used four outputs into a darlington array. which was in turn connected to a 12V supply for the motor. there were also some switches to control on/off etc.
darlington array datasheet (ULN2803A): http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXssxrt.pdf
After testing for 10 minutes the motor stopped, presumably because the propstick also seemed to have lost power: the "power indicator led" that is on the initial setup on the breadboard went out, the LEDs on the propstick flashed briefly as it failed. the supply was fine, still producing 5V.
can anyone see something wrong with my setup that could cause the propstick to stop working?
The USB cable (supplied) was connected at the time the chip failed, and the cable no longer functions with other devices, which makes me suspicious that this may have shorted and damaged the chip. It doesnt appear to be very strong, but could it really cause that much damage to the chip if it failed?
Essentially I want to know:
1) Was this my fault for incorrectly using the chip or was it faulty and therefore should be replaced by parallax,
2) how do I ensure that it never happens again?
Thanks guys,
Woody
After receiving the "propeller education kit" and setting up the initial circuit I found that the 5V regulator didnt work, with a 9V battery input across "P+" and "0" terminal, there was also 9V across the "5" and "0" pins. Since i had a nice expensive power supply that could produce a very reliable 5V I removed the regulator and connected the power supply up instead. I'm reasonably sure that this isn't the cause of the problem, but I could be wrong.
Setting up the initial testing circuits showed no problems, they all functioned fully.
My next circuit was a very rudimentary stepper motor control, see attachment for breadboard layout. The setup used four outputs into a darlington array. which was in turn connected to a 12V supply for the motor. there were also some switches to control on/off etc.
darlington array datasheet (ULN2803A): http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXssxrt.pdf
After testing for 10 minutes the motor stopped, presumably because the propstick also seemed to have lost power: the "power indicator led" that is on the initial setup on the breadboard went out, the LEDs on the propstick flashed briefly as it failed. the supply was fine, still producing 5V.
can anyone see something wrong with my setup that could cause the propstick to stop working?
The USB cable (supplied) was connected at the time the chip failed, and the cable no longer functions with other devices, which makes me suspicious that this may have shorted and damaged the chip. It doesnt appear to be very strong, but could it really cause that much damage to the chip if it failed?
Essentially I want to know:
1) Was this my fault for incorrectly using the chip or was it faulty and therefore should be replaced by parallax,
2) how do I ensure that it never happens again?
Thanks guys,
Woody
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Comments
welcome to the propeller-forum!
feel free to ask as many questions as you like.
providing information is always good. (like the datasheet of the darlington array)
The picture is not very sharp so it is hard to analyse something.
We would need a high resolutio and sharp picture to analyse this.
If you could provide a schematic of how everything is wired this would help a lot.
There must have been a reason why your 5V regulator got damaged. If you have no idea why,
I assume that you have overlooked something like a short circuit.
In general I recommend using a DIP40 propellerchip as they cost only $8. (instead of a prop-stick usb $50)
I recommend this even more if you might be not very familiar with electronics.
Did you test another USB cable?
If the original cable got damaged it must have encountered quite a lot mechanical stressing.
Do you have a digital multimeter to check each of the 4 wires inside of the USB-cable?
Did you try to identify the prop-chip in the propellertool by hitting F7?
If you use a proper working USB-cable does the FTDI-Chip gets recognized by the PC?
About avoiding damages in the future:
Do all softwaretests just with 5V connected to the Vin pin. (pin no 12)
be VERY sure that 5V is NEVER connected to pin 32 (named Vdd) this pin is just 3.3V. If connect more than 3.3V the propchip gets damaged!
If all pretests were succesfully connect to additional hardware. Before switching on the powersupply double-check if the wiring is correct.
To get even more security you can use optocouplers which completely isolates external hardware electrically from the propeller-chip
@parallax in the Setup and Testing - PropStick USB PE Platform manual the wire from the 5V regulator to the Vin-Pin of the propstick has the same color red as all other +-wires wich are only 3.3V
This is source for damages. This wire should have a different color to indicate its higher voltage.
best regards
Stefan
The 5V regulator seemed to be damaged as it was received, I checked the setup very carefully and found everything identical to the recommended wiring.
using a second usb cable produces the same results: the lights on the propstick flash brief;y but the power light doesnt glow dimly as it should normally. (i have tested the LED to check it works too) the computer wont be able to detect the chip because it is unpowered, so a functioning usb cable doesnt detect the ship either.
the 5V and 3V supplies are definitely isolated from each other, i originally used a different colour on purpose.
Thanks,
Woody
See attached.
You can't be "isolated."
If you had already had troubles with the 5v regulator, Have you checked the output of the 3.3v regulator (on the prop stick)?