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#1
A20 / Re: OLinuXino Lime 2 fails to ...
Last post by LubOlimex - Today at 11:35:04 AMI wonder how do you apply the power supply? Via the power jack?
Did you try with more than one power adapter?
Does the issue persists with more than one board?
Did you try with more than one power adapter?
Does the issue persists with more than one board?
#2
A20 / Change clock frequency of i2c ...
Last post by tedium - Today at 11:31:26 AMHi
I am trying to change the I2C clock frequency on my 'A20-OLinuXino-LIME2' with the Image 'A20-OLinuXino-bullseye-minimal-20220928-143706.img'.
I have done some research on this topic and came across Device Tree Overlays which an be linked in the '/boot/uEnv.txt' file. So my question is how do I find the right device the in device tree?
If I search the device tree file I get five results:
And I don't know which is the one I should overlay. Another point is, that in these devices there is no clock frequency attribute, only the clocks attribute which contains two addresses of clocks.
This is my fist post in this forum, I hope my text structure is okey and you understand my questions.
Thanks in advance
I am trying to change the I2C clock frequency on my 'A20-OLinuXino-LIME2' with the Image 'A20-OLinuXino-bullseye-minimal-20220928-143706.img'.
I have done some research on this topic and came across Device Tree Overlays which an be linked in the '/boot/uEnv.txt' file. So my question is how do I find the right device the in device tree?
If I search the device tree file I get five results:
Code Select
i2c@1c2ac00 {
compatible = "allwinner,sun7i-a20-i2c\0allwinner,sun4i-a10-i2c";
i2c@1c2b000 {
compatible = "allwinner,sun7i-a20-i2c\0allwinner,sun4i-a10-i2c";
i2c@1c2b400 {
compatible = "allwinner,sun7i-a20-i2c\0allwinner,sun4i-a10-i2c";
i2c@1c2b800 {
compatible = "allwinner,sun7i-a20-i2c\0allwinner,sun4i-a10-i2c";
i2c@1c2c000 {
compatible = "allwinner,sun7i-a20-i2c\0allwinner,sun4i-a10-i2c";
And I don't know which is the one I should overlay. Another point is, that in these devices there is no clock frequency attribute, only the clocks attribute which contains two addresses of clocks.
This is my fist post in this forum, I hope my text structure is okey and you understand my questions.
Thanks in advance
#3
A20 / Re: OLinuXino Lime 2 fails to ...
Last post by Julien - June 01, 2023, 12:41:24 PM> When this happened, was the procedure you described followed ?
No. If this happens, the process is stopped and the power is on.
> It is important to notice that in the design we have placed big capacitor [...]
If the AC power is of for two minutes, do you think it is possible that the capacitor is not fully discharged ?
However, we're going to do the test by removing it.
No. If this happens, the process is stopped and the power is on.
> It is important to notice that in the design we have placed big capacitor [...]
If the AC power is of for two minutes, do you think it is possible that the capacitor is not fully discharged ?
However, we're going to do the test by removing it.
#4
A20 / Re: OLinuXino Lime 2 fails to ...
Last post by LubOlimex - May 31, 2023, 04:03:25 PM> That's the problem: for unknown reasons, the system fails to start at random times.
- When this happened, was the procedure you described followed (aka "We detect that the AC power is off and shut down the system. After two minutes, the power is restored and the system starts 'normally'.")?
- Or was it quick disconnect of power supply, attach power supply?
It is important to notice that in the design we have placed big capacitor near the power jack (C200 in most revisions). It serves to prevent small and quick glitches to the power supply, the downside is that it requires some time to discharge after power supply goes missing. And if you restore the power supply before it is discharged, there would be a problem. This problem will persist no matter if you have battery or not. You might try to improve behavior by unsoldering C200, this way power up and power down would be more responsive. The best test is empirical.
- When this happened, was the procedure you described followed (aka "We detect that the AC power is off and shut down the system. After two minutes, the power is restored and the system starts 'normally'.")?
- Or was it quick disconnect of power supply, attach power supply?
It is important to notice that in the design we have placed big capacitor near the power jack (C200 in most revisions). It serves to prevent small and quick glitches to the power supply, the downside is that it requires some time to discharge after power supply goes missing. And if you restore the power supply before it is discharged, there would be a problem. This problem will persist no matter if you have battery or not. You might try to improve behavior by unsoldering C200, this way power up and power down would be more responsive. The best test is empirical.
#5
A20 / Re: OLinuXino Lime 2 fails to ...
Last post by Julien - May 31, 2023, 03:09:42 PMWe have updated our test, now using a Li-Po battery.
We detect that the AC power is off and shut down the system. After two minutes, the power is restored and the system starts 'normally'.
That's the problem: for unknown reasons, the system fails to start at random times.
The AXP209 doesn't supply any power.
I have to disconnect and reconnect the battery and AC power to get it to boot.
Or press the reset button (middle button).
Do you have any information on this?
Thanks you in advance !
We detect that the AC power is off and shut down the system. After two minutes, the power is restored and the system starts 'normally'.
That's the problem: for unknown reasons, the system fails to start at random times.
The AXP209 doesn't supply any power.
I have to disconnect and reconnect the battery and AC power to get it to boot.
Or press the reset button (middle button).
Do you have any information on this?
Thanks you in advance !
#6
STMP1 / Re: Board occasionally will no...
Last post by LubOlimex - May 31, 2023, 08:13:45 AMQuoteAny hardware mitigation on our side will take months to get into production due to where we are in the production lifecycle. Any update the the SOM if it reduces the time window (and probability) of the hangup occurring would be welcome. The change would need to come from Olimex as we won't do rework on a third-party OEM component. But we would welcome the option to purchase an updated rev from Olimex.
As long as you have tested and confirmed it works for you we can probably do it, but I am not the person that can promise it. It has to reach the boss, so please drop an e-mail at support@olimex.com describing the issue and linking this thread. Keep me updated how testing with the resistor goes.
#7
STMP1 / Re: Board occasionally will no...
Last post by thom_nic - May 30, 2023, 08:40:03 PMThanks for the update.
We will do some testing with a C37 resistor at some point when we have a free tech to run the setup and test, to quantify the before and after behavior.
Any hardware mitigation on our side will take months to get into production due to where we are in the production lifecycle. Any update the the SOM if it reduces the time window (and probability) of the hangup occurring would be welcome. The change would need to come from Olimex as we won't do rework on a third-party OEM component. But we would welcome the option to purchase an updated rev from Olimex.
If it helps I can provide our company name so you can look up our purchase history. We're not huge quantity but we've been regular purchasers of your SOMs for years.
We will do some testing with a C37 resistor at some point when we have a free tech to run the setup and test, to quantify the before and after behavior.
Any hardware mitigation on our side will take months to get into production due to where we are in the production lifecycle. Any update the the SOM if it reduces the time window (and probability) of the hangup occurring would be welcome. The change would need to come from Olimex as we won't do rework on a third-party OEM component. But we would welcome the option to purchase an updated rev from Olimex.
If it helps I can provide our company name so you can look up our purchase history. We're not huge quantity but we've been regular purchasers of your SOMs for years.
#8
STMP1 / Re: Board occasionally will no...
Last post by LubOlimex - May 30, 2023, 03:30:47 PMWe tested a few different hardware values but they don't fix this sort of behavior completely. I still managed to hang it every time albeit harder.
My advice is to test with the 330 Ohm 0805 resistor on the C37 location and see if that works better for you. However, again notice I managed to hang the board with it too.
You might need to also think of an alternative solution.
My advice is to test with the 330 Ohm 0805 resistor on the C37 location and see if that works better for you. However, again notice I managed to hang the board with it too.
You might need to also think of an alternative solution.
#9
STMP1 / Re: Board occasionally will no...
Last post by thom_nic - May 30, 2023, 03:13:08 PMPlease let me know what you conclude in your investigation. Anything we can do to minimize the time window of this occurring will be beneficial.
We're buying these in quantity from you already and if there's an SMT mod on the SOM we may see if we can order these from you with the mod in place. I'm going to talk with the HW/EE lead today (I'm the SW guy) and will follow up.
We're buying these in quantity from you already and if there's an SMT mod on the SOM we may see if we can order these from you with the mod in place. I'm going to talk with the HW/EE lead today (I'm the SW guy) and will follow up.
#10
STMP1 / Re: Board occasionally will no...
Last post by LubOlimex - May 30, 2023, 08:56:20 AMGlad that it was identified and confirmed, this is usually the hardest part of fixing an issue.
If you are not going to use battery (if your design doesn't allow for it), you can test by adding 330 Ohm resistor (at least 100 milliwatt, any PTH size works, if using SMT then at least 0805 size no smaller) on the IPS line. If it was me the easiest place I can attach it is on C37 location, above the reset button, which by default is not placed, this leaves us nice free pads to attach such resistor.
Edit: I actually tested this now and it feels for me that it improves the start up behavior, and haven't noticed a major downside so far.
We would also be doing our own investigation and evaluation of this behavior, but not sure if behavior can be completely fixed without sacrifices. Overall, it is impossible to be able to completely avoid it, any device that gets powered down in a instant and then powered up a second later is bound to malufcution after a number of such cycles. There are a lot of things going on, like start-up currents and so on.
If you are not going to use battery (if your design doesn't allow for it), you can test by adding 330 Ohm resistor (at least 100 milliwatt, any PTH size works, if using SMT then at least 0805 size no smaller) on the IPS line. If it was me the easiest place I can attach it is on C37 location, above the reset button, which by default is not placed, this leaves us nice free pads to attach such resistor.
Edit: I actually tested this now and it feels for me that it improves the start up behavior, and haven't noticed a major downside so far.
We would also be doing our own investigation and evaluation of this behavior, but not sure if behavior can be completely fixed without sacrifices. Overall, it is impossible to be able to completely avoid it, any device that gets powered down in a instant and then powered up a second later is bound to malufcution after a number of such cycles. There are a lot of things going on, like start-up currents and so on.