Still no go yet! I need confirming with the designer prior doing some damages to this beneficial board!
Power up problems
I have been progressing my build of an integrated BBB, DSP, DAC using I2S directly from BBB to minisharc DSP.
Having built linear power supplies for the different elements I have finally hooked it all up but have a problem with the BBB powering up. The BBB is supplied by a regulated 5V supply using an LT3080. I am using an external oscillator which is powered from the same transformer as the BBB but a separate winding via a TPS7A4700 regulator. When I switch on power with both of these connected the BBB does not power up. If I power up the oscillator first then plug in power to the BBB from the PSU described above, the BBB powers up fine. I haven't tried it the other way round (i.e. BBB first) as that is difficult because of the setup.
Earlier I had them on separate supplies (BBB plug pack SMPS, oscillator linear) but both supplies powered off the same power panel and switched on together. This also worked fine.
So I am thinking its some sort of timing issue? Maybe I need a delay circuit for either the oscillator or the BBB.
I know there has been extensive discussion around power sequencing but I'm afraid I did't follow that closely as I have never had any issues.
Any help or suggestions welcome.
I have been progressing my build of an integrated BBB, DSP, DAC using I2S directly from BBB to minisharc DSP.
Having built linear power supplies for the different elements I have finally hooked it all up but have a problem with the BBB powering up. The BBB is supplied by a regulated 5V supply using an LT3080. I am using an external oscillator which is powered from the same transformer as the BBB but a separate winding via a TPS7A4700 regulator. When I switch on power with both of these connected the BBB does not power up. If I power up the oscillator first then plug in power to the BBB from the PSU described above, the BBB powers up fine. I haven't tried it the other way round (i.e. BBB first) as that is difficult because of the setup.
Earlier I had them on separate supplies (BBB plug pack SMPS, oscillator linear) but both supplies powered off the same power panel and switched on together. This also worked fine.
So I am thinking its some sort of timing issue? Maybe I need a delay circuit for either the oscillator or the BBB.
I know there has been extensive discussion around power sequencing but I'm afraid I did't follow that closely as I have never had any issues.
Any help or suggestions welcome.
Further testing and even more confused.
It seems its not to do with the power to the oscillator. With the P9 connections disconnected, using the normal power socket in the BBB - if I switch on power to the PSU with the plug in the power socket it does not power up but if I remove and replug the power with power already on it powers up.
However if I try switching on power using a plug pack SMPS with the plug already in the socket - it powers up.
But I have another BBB with linear supply and it powers up fine.
CONFUSED!
EDIT: My be getting close to this, sorry if I am wasting your time. The LT3080 needs at least .5ma load to operate, without any load output voltage is same as input (about 7.5v in my case). I had already added a load resistor but I am wondering now if it takes some small amount of time to settle and the BBB is seeing the higher voltage initially and has some protection circuitry to prevent over voltage.
If anybody understand the LT3080 and the BBB protection circuitry would be grateful to hear.
It seems its not to do with the power to the oscillator. With the P9 connections disconnected, using the normal power socket in the BBB - if I switch on power to the PSU with the plug in the power socket it does not power up but if I remove and replug the power with power already on it powers up.
However if I try switching on power using a plug pack SMPS with the plug already in the socket - it powers up.
But I have another BBB with linear supply and it powers up fine.
CONFUSED!
EDIT: My be getting close to this, sorry if I am wasting your time. The LT3080 needs at least .5ma load to operate, without any load output voltage is same as input (about 7.5v in my case). I had already added a load resistor but I am wondering now if it takes some small amount of time to settle and the BBB is seeing the higher voltage initially and has some protection circuitry to prevent over voltage.
If anybody understand the LT3080 and the BBB protection circuitry would be grateful to hear.
Last edited:
ChrisMmm: are you trying to destroy your BBB?
You need to look up this protection info in the datasheet of power module TPS65217 | Power Management Multi-Channel IC (PMIC) Solutions | Power Management | Description & parametrics
You need to look up this protection info in the datasheet of power module TPS65217 | Power Management Multi-Channel IC (PMIC) Solutions | Power Management | Description & parametrics
ChrisMmm: are you trying to destroy your BBB?
You need to look up this protection info in the datasheet of power module TPS65217 | Power Management Multi-Channel IC (PMIC) Solutions | Power Management | Description & parametrics
Thanks, well datasheet says there is over-voltage protection up to 20v, if the input voltage to the AC pin is over the max (5.8V) the chip goes to "off" mode.
I am guessing this is what is happening and that the LT3080 is going over-voltage for the short time it is settling this triggering the "off" state. I have no real proof as I only ever see it registering 5.07v but that seems to be the best explanation.
I have another BBB powered by a linear supply with an LM1085 - that has never exhibited this problem so I think it is specific to the LT3080. I will try another regulator, have a LM1086 handy or a 5v LM2940.
No sync
Happy New Year.
I have installed the latest botic on my BBB and am trying to connect to Buffalo III via I2S.
On the BBB Pin 31 goes to D0 on the buffalo, 29 to D1 and 42 to D2, grnnto grnd. The Buffalo is set for I2s/Dsd. It works fine when fed from the Amanero board.
All the Botic settings are default. I get no sync. In fact
cat proc/asound/card0/pcm0p/sub0/hw_params
returns
No setup
It looks to me like an alsa issue but I may be wrong.
TIA
Happy New Year.
I have installed the latest botic on my BBB and am trying to connect to Buffalo III via I2S.
On the BBB Pin 31 goes to D0 on the buffalo, 29 to D1 and 42 to D2, grnnto grnd. The Buffalo is set for I2s/Dsd. It works fine when fed from the Amanero board.
All the Botic settings are default. I get no sync. In fact
cat proc/asound/card0/pcm0p/sub0/hw_params
returns
No setup
It looks to me like an alsa issue but I may be wrong.
TIA
I use the following when using the Botic drivers/I2S:
cat /proc/asound/BOTICAudio/pcm0p/sub0/hw_params
giulio: please recheck the http://bbb.ieero.com/ and if you miss some infirmation, please let me know
Don't forget to connect DAC BCLK to BBB pin P9_31.
Don't forget to connect DAC BCLK to BBB pin P9_31.
D0 on the Buffalo is BCLK
D1 is LRCK
D2 is Data
I have tried to follow the instructions on the ieero website to the letter.
What I find strange is that even if the connection were wrong I thought that
cat /proc/asound...
should return some meaningful info.
The BBB works fine when connected to the Buffalo via the Amanero using Voyage mpd.
D1 is LRCK
D2 is Data
I have tried to follow the instructions on the ieero website to the letter.
What I find strange is that even if the connection were wrong I thought that
cat /proc/asound...
should return some meaningful info.
The BBB works fine when connected to the Buffalo via the Amanero using Voyage mpd.
It works fine with Buffalo 3 for me, so there must be another catch. Can you post photos? Do you have oscilloscope to check if there is signal on I2S output pins from BBB.
The hw_params file in the /proc/asound/... should contain "closed" when audio channel is not used. Otherwise there is audio format specified.
Also I assume for I2S playbacj you are using Botic image for BBB and not Voyage MPD, right?
The hw_params file in the /proc/asound/... should contain "closed" when audio channel is not used. Otherwise there is audio format specified.
Also I assume for I2S playbacj you are using Botic image for BBB and not Voyage MPD, right?
BBB Cape with DDDAC1794
Hi Miero, thanks a lot for your great work, and thanks to Russ and the DIY folk for ideas around the cape.
While waiting for Russ' cape I built my own protocape with BBB Rev. C, works great in I2S mode connected to a DDDAC1794. After some tests with a DSD DAC I'll design my own board layout.
There is still one hardware issue. My power supply uses a small LiPo for safe shutdown (following discussion in this thread), but when BBB is totally shut down there is still a small current on the 3V3 power line on the BBB by LiPo. So after 24h hours the LiPo is dead. Thats why I switch the LiPo shortly off after complete shutdown of BBB by a small 3V3 relay, then it's fine. Any other ideas? The relay cannot control by BBB.
Hi Miero, thanks a lot for your great work, and thanks to Russ and the DIY folk for ideas around the cape.
While waiting for Russ' cape I built my own protocape with BBB Rev. C, works great in I2S mode connected to a DDDAC1794. After some tests with a DSD DAC I'll design my own board layout.
There is still one hardware issue. My power supply uses a small LiPo for safe shutdown (following discussion in this thread), but when BBB is totally shut down there is still a small current on the 3V3 power line on the BBB by LiPo. So after 24h hours the LiPo is dead. Thats why I switch the LiPo shortly off after complete shutdown of BBB by a small 3V3 relay, then it's fine. Any other ideas? The relay cannot control by BBB.
Attachments
I don't understand this statement well.
AC and USB is off, and the battery is connected to BBB using battery connector, right?
But the BBB draws power from battery even when it is in OFF mode?
Also I've never tried battery, so I don't have experience with this. Just trying to guess what is going on.
Maybe you can use BBB support forum for that question: https://groups.google.com/forum/?place=forum/beagleboard#!forum/beagleboard
I had gotten the battery idea from here:
BeagleBone Black: BBB - Rechargeable on-board b... | element14
They might be able to help?
BeagleBone Black: BBB - Rechargeable on-board b... | element14
They might be able to help?
Yes, BBB was switched off, by switching off 5V supply via cape (USB and AC are off) or by SSH command "shutdown -hP now".
BBB in my setup is always connected via BAT connector to 3.7V LiPo and the 3V3 line (P9.3-4) is still on after shutdown. I tested this with different BBB boards (element14, Rev.C). Maybe the TP65217 is not absolutely off after this procedure? Shortly switching off LiPo after BBB shutdown is a solution but maybe there is a better way. I'm still on investigating but if anybody has tip...
BBB in my setup is always connected via BAT connector to 3.7V LiPo and the 3V3 line (P9.3-4) is still on after shutdown. I tested this with different BBB boards (element14, Rev.C). Maybe the TP65217 is not absolutely off after this procedure? Shortly switching off LiPo after BBB shutdown is a solution but maybe there is a better way. I'm still on investigating but if anybody has tip...