You really need a 3.3V regulator near the power pins, the inductance of wires from the bench supply tend to make the system unstable.
The Omega 2 is designed to be used as a mezzanine module on a circuit card with good power regulation. It's not so forgiving as a stand alone module.
@Chris-Drake said in Can I run real-time applications on Omega?:
Nothing can "crash" when it has no control
An operating system that doesn't have control isn't really an operating system. It is possible to write software that can replace the various functions of the operating system that are necessary for your application, but on a complex processor this is non-trivial. I would expect an effort counted in man-months (and probably a lot of them) for someone familiar with the this sort of thing to do what you've described. This is the essence of the first reply.
Consider this: X Y Problem
If you really need to generate time critical software bit banged I/O on a small single board computer, one of the BeagleBone products would be a better starting point than the Omega. The processor chip used on those boards include both a Linux/ARM main processor and two fast real time processors, so you (relatively) easily get the benefit of both a high level OS and fast hard real time capability.
It is possible to totally mask all interrupts. Shortly thereafter the operating system would crash.
Yes it is possible to vector all interrupts to your software. You would then have to write an operating system.
See first bullet.
Waste electricity?
Linux systems have a task priority scheme. See the "nice" command. This probably doesn't get you what you want.
@Andrey-Shafray said in Omega2 boot loop:
After message
[ 18.768343] EEPROM:Read from [factory] offset 0x0,length 0x400.go reboot
Power to the Omega 2 is probably inadequate. The next boot message after "EEPROM: . . ." is when the wifi turns on and there is a surge in current draw. Instead the processor has rebooted before that message can be output.
@Mark-B said in Omega2+ hot hot hot:
If you have the ability it might be worth measuring current draw and comparing with others. In quick search I found one poster seeing 170 mA. I'll to remember to measure and post mine a bit later.
Just to follow up on this. With my Omega2+ running on a proto-board with nothing but a linear regulator I got the following data points. This is monitoring current with a inexpensive USB voltmeter which has questionable accuracy at low current levels and updates about twice per second.
idle current ~= 110 mA
current running cpu intensive task* ~= 170 mA
current running wifi task** ~= 280 mA average, peaks around 350 mA - board is noticeably warmer to the touch, but not hot
I think this suggests that CPU activity doesn't matter much. If an Omega2 is particularly warm (and not otherwise defective) it's likely because the wifi activity is high for some reason.
* - Python for cpu task gives near 100% cpu
import random
import math
x = 0
for m in range(0,1000000): x = x + math.sin(random.uniform(0.0,1.0))
print(x)
** - Python for wifi task run via ssh over wifi gives about 50% cpu load
for k in range(0,10000):
__ for m in range(0,k): print(m,k)
Edit to add: I see similar numbers for my Omega 2 (not plus) except "wifi" numbers are higher, with and average of about 330 and peaks up to 420 mA.
Also, the current spikes are apparent in the boot process where the serial debug suggests wifi activity with the first about 20 seconds into boot.
@Alessandro-Nichelini said in Factory Reset due to "invisible" Omega2:
@Mark-B
Thank you for your answer.
For the power supply i'm using a MB102 (http://www.petervis.com/Raspberry_PI/Breadboard_Power_Supply/YwRobot_Breadboard_Power_Supply.html) which should supply stable 3.3 V. However I tried also to connect the Omega2 to the arduino 3.3V Out but nothing changed...
When I was seeing the boot loop I was using an MB102 with 10 cm Dupont connector wires as well.
You might try shortening your leads to the Omega2 as much as practical, use heavier gauge wire, and maybe put a capacitor on the Omega2 power pins, but I'm not convinced this is a stable setup.
I (and many others) had much the same problem with the ESP8266 boards with off-board power regulation which can be fixed in a similar manner.
Edit to add: From another current thread, I think the last boot line I saw on the serial port was "[ 18.882660] EEPROM:Read from [factory] offset 0x0,length 0x400." Then it started to exercise the WiFi stuff and immediately rebooted.
@Costas-Costas said in [resolved] Help, My Omega2 plus can't start successfully:
@Pierre-Rossinès said in [resolved] Help, My Omega2 plus can't start successfully:
@ccs-hello
The worst part is that sometimes they work, sometimes they don't.That's the problem I have with my 2+'s wired up to AMS1117's. They will normally run for 24 to 36 hours and then fail. Don't know if they get too hot, run out of memory or receive a power spike. When I reboot them sometimes they boot up and sometimes they don't. If they don't bootup after a few tries I leave them for perhaps 30 to 60 minutes and generally they do bootup. Bit of a mystery.
My Omega 2+ had a similar problem in that it would not reboot after it had been running a while (10 or 15 minutes was enough). After sitting unpowered for a while, it would happily boot again and run without apparent issue.
Guessing that there was an intermittent thermally sensitive connection somewhere on the board that affected start up, I reflowed the solder on all exposed connections with an SMD hot air tool and the problem seems to have gone away. So with a sample set of one, it looks like a manufacturing defect in my case.
My Omega 2 (not plus) didn't have this particular issue.
Both had problems during boot when running from inadequate power. The symptom of that problem is running normally through startup, as monitored on the serial port, to the point where wifi was first brought up, about 18-20 seconds into the boot sequence. At that point they would reset and repeat this process indefinitely.
@Akshat-Mehra Sorry to hear that. I've done similar things an embarrassing number of times, some of them far more visually spectacular.
@Ken-Conrad said in Omega2 expansion dock alternative?:
Yes, the 16 hole 2mm headers are a bit rare. Is $1 per Omega delivered to your mail box cheap enough? Available here in a few days, after the Rooster holiday in China ends - http://www.ebay.com/itm/182057549028?_trksid=p2057872.
For what it's worth I got 2 mm 16 pin headers from this supplier and received them to the US in 8 days. That's probably not typical though.
Prior to getting 2 mm bits, I built up a jig on a 0.100" perf board with individual sockets for power pins, serial I/O, and locating sockets on the corner pins (2 of which are GND anyway). I put the socket headers on the Omega, inserted them through the closest hole in the 0.100" (so they were angled to go from 0.100" to 2 mm), and soldered in place. The socket headers I had were cannibalized from a wire-wrap DIP socket I had in the junk pile.
@ccs-hello etal
I posted the results of some testing I did using a little different procedure than "ccs-hello" and saw indications of spikes to 420 mA on one of my Omegas. I've pasted that post below. I second ccs-hello's comments about wire gauge and filter capacitors and would add that you want the wires short and the 3.3 V capacitor close to the Omega power pins.
Pasted post follows:
@Mark-B said in Omega2+ hot hot hot:
With my Omega2+ running on a proto-board with nothing but a linear regulator and 22 uF tantalum capacitor on 3.3 V, I got the following data points. This is monitoring current with a inexpensive USB voltmeter which has questionable accuracy at low current levels and updates about twice per second, so I'm probably not seeing the absolute peak current.
idle current ~= 110 mA
current running cpu intensive task* ~= 170 mA
current running wifi task** ~= 280 mA average, peaks around 350 mA - board is noticeably warmer to the touch, but not hot
I think this suggests that CPU activity doesn't matter much. If an Omega2 is particularly warm (and not otherwise defective) it's likely because the wifi activity is high for some reason.
* - Python for cpu task gives near 100% cpu
import random
import math
x = 0
for m in range(0,1000000): x = x + math.sin(random.uniform(0.0,1.0))
print(x)
** - Python for wifi task run via ssh over wifi gives about 50% cpu load
for k in range(0,10000):
__ for m in range(0,k): print(m,k)
Edit to add: I see similar numbers for my Omega 2 (not plus) except "wifi" numbers are higher, with and average of about 330 and peaks up to 420 mA.
Also, the current spikes are apparent in the boot process where the serial debug suggests wifi activity with the first about 20 seconds into boot.
You really need a 3.3V regulator near the power pins, the inductance of wires from the bench supply tend to make the system unstable.
The Omega 2 is designed to be used as a mezzanine module on a circuit card with good power regulation. It's not so forgiving as a stand alone module.
help("modules") in Python should list the modules installed. Of course one would have to install Python Light in order to do this.
opkg list | grep python from the command line should list the modules available.
@Gökhan-Türkeli
I had problems running from an MB102 power module. Using relatively heavy gauge wire and short runs would probably help. Ultimately I built a small board with the LM1117 regulator and a tantalum bypass capacitor very close to the Omega power pins to get reliable operation.
An easy way to test your USB to Serial converter is to wire the Tx and Rx pins together and verify that it can talk to itself. If this is the case then your device drivers are working. When connecting to an external serial device (the Omega) you may have to go Tx to Tx or you may have to go Tx to Rx between the device and USB serial. Labeling of USB to Serial devices is inconsistent.
The Omega should be warm to the touch, but not so hot you can't keep a finger on it indefinitely. Current draw is a few hundred milliamps and fluctuates largely depending upon WiFi activity.
I posted some power data in this thread link text
@Costas-Costas said in [resolved] Help, My Omega2 plus can't start successfully:
@Pierre-Rossinès said in [resolved] Help, My Omega2 plus can't start successfully:
@ccs-hello
The worst part is that sometimes they work, sometimes they don't.That's the problem I have with my 2+'s wired up to AMS1117's. They will normally run for 24 to 36 hours and then fail. Don't know if they get too hot, run out of memory or receive a power spike. When I reboot them sometimes they boot up and sometimes they don't. If they don't bootup after a few tries I leave them for perhaps 30 to 60 minutes and generally they do bootup. Bit of a mystery.
My Omega 2+ had a similar problem in that it would not reboot after it had been running a while (10 or 15 minutes was enough). After sitting unpowered for a while, it would happily boot again and run without apparent issue.
Guessing that there was an intermittent thermally sensitive connection somewhere on the board that affected start up, I reflowed the solder on all exposed connections with an SMD hot air tool and the problem seems to have gone away. So with a sample set of one, it looks like a manufacturing defect in my case.
My Omega 2 (not plus) didn't have this particular issue.
Both had problems during boot when running from inadequate power. The symptom of that problem is running normally through startup, as monitored on the serial port, to the point where wifi was first brought up, about 18-20 seconds into the boot sequence. At that point they would reset and repeat this process indefinitely.
@Akshat-Mehra Sorry to hear that. I've done similar things an embarrassing number of times, some of them far more visually spectacular.
You also want to use moderately heavy gauge wire (say 22 gauge) between your regulator (or lab power supply) and the Onion Vcc and Gnd pins.
Better would be to put the regulator and bypass capacitors on a small assembly directly connected to the onion pins. Then the wires to the regulator are much less critical.
@Akshat-Mehra What are you using for a power supply? Have you verified that the voltage at the Omega power pins is 3.3 V?
@Chris-Stratton said in Did WinSCP just fry my Onion?:
Really? How many actual soundly engineered products are built around a pi? There have been a few attempts, but it's not very suitable for real use, which becomes obvious when you seriously try
Interesting tangent this thread has taken. The Raspberry Pi is aimed at the education market, not the commercial product market. I don't think they could be more clear about that. Certainly they have been adopted by hobbyists and have found a niche in some products, but, except for the "compute module" variant the latter isn't something they are targeting. Moreover the Pi is more of a small server or high end graphic user interface sort of device with some GPIO, not really in competition with node devices like the Omega or ESP8266.
@Chris-Drake said in Can I run real-time applications on Omega?:
Nothing can "crash" when it has no control
An operating system that doesn't have control isn't really an operating system. It is possible to write software that can replace the various functions of the operating system that are necessary for your application, but on a complex processor this is non-trivial. I would expect an effort counted in man-months (and probably a lot of them) for someone familiar with the this sort of thing to do what you've described. This is the essence of the first reply.
Consider this: X Y Problem
If you really need to generate time critical software bit banged I/O on a small single board computer, one of the BeagleBone products would be a better starting point than the Omega. The processor chip used on those boards include both a Linux/ARM main processor and two fast real time processors, so you (relatively) easily get the benefit of both a high level OS and fast hard real time capability.
@Ken-Conrad said in Omega2 expansion dock alternative?:
Yes, the 16 hole 2mm headers are a bit rare. Is $1 per Omega delivered to your mail box cheap enough? Available here in a few days, after the Rooster holiday in China ends - http://www.ebay.com/itm/182057549028?_trksid=p2057872.
For what it's worth I got 2 mm 16 pin headers from this supplier and received them to the US in 8 days. That's probably not typical though.
Prior to getting 2 mm bits, I built up a jig on a 0.100" perf board with individual sockets for power pins, serial I/O, and locating sockets on the corner pins (2 of which are GND anyway). I put the socket headers on the Omega, inserted them through the closest hole in the 0.100" (so they were angled to go from 0.100" to 2 mm), and soldered in place. The socket headers I had were cannibalized from a wire-wrap DIP socket I had in the junk pile.