Possible header configurations and RTC question


#1

Hi all, I have couple questions to which I cannot find clear answer:

  1. Is it possible to power supply BPi-M2+ over header ? If no, then, are there any workarounds/reworks I can made to achieve that ?
  2. What is maximum number of USB and UART ports I can use on BPi-M2+ assuming configuration of some pins on header ?
  3. Is BPi-M2+ immune to RTC issue ? I can’t see any RTC on board so I assume it is not. I see typically you use external DS1307, are there any other solutions worth consider ?

I would be glad to any materials that describe RTC issue in more technical terms.


CON1 (SIP2-254) and USB-DM3 usage
#2

You can have a look into schematics (if you trust in the contents – which is nothing I really would consider :wink: )


#3

I saw that thread. This doesn’t help me much or maybe I’m missing something.

Schematics doesn’t contain layout, so I have no idea how power barrel is connected and how 5V gets to header. If it is connected directly I probably can use pin 2 or pin 4 to provide 5V and power on board in that way. I don’t have board, so I cannot try. Also if this can damage board I would like to know that without trying.

Do you know anything about RTC ?


(BlinkQ) #4

it has four usb and three uart, and RTC can use this module: https://bananapi.gitbooks.io/bpi-accessories/content/rtcmodule.html


#5

Where is the 4th USB port exposed please?


(BlinkQ) #6

as everyone knows two USB port and OTG, and the 4th port is CON1, I see it from schematic at page 5. I asked for the usb pin from M1, again, and again. I see it on BPI-M2+, but I not yet tested it.


#7

Don’t we already know that schematic is wrong? And where is this CON1 connector on the PCB? I can not spot it.


(BlinkQ) #8

I found two hole near the rx & tx, I guess it is CON1. I’ll confirm it later. or you know is it what port?


#9

Ah, now I see it (and spotted the same for BPi M3 back then, there the fourth port coming from the USB hub there is also exposed for soldering at the same location). Would be great if you could check! I would immediately update the wiki after confirmation.


(BlinkQ) #10

I test it using CH340 module on M2+ and M3, it can find usb device on M3 through the two hole, but on M2+ I can’t find any new device. maybe it not CON1 or no configure in system?


#11

Most probably the latter: https://github.com/igorpecovnik/lib/blob/master/config/fex/bananapim2plus.fex#L865-L872

Just change usb_used = 1, then recompile script.bin, reboot and give it a try again please :slight_smile:


(BlinkQ) #12

after change it, i find the usb device on CON1, and i will write it next day


#13

Well after the change in fex file the port will be available to the kernel even if the USB lines aren’t exposed physically. So looking forward to your testing :slight_smile:

On a related note: We have just figured out how to reliably use H3 with 3.4.x kernel as USB Ethernet gadget device: http://igor2.repo.hu/tmp/opi_usb_gadget.txt (requires one smallish kernel change and should also work with BPi M3 where it makes not that much sense since only 1 real USB port there is available)


(BlinkQ) #14

I make an usb port with four lines

because i will use 40pin connector, so I did not solder two pins

I join red line to pin2 and join black line to pin6, other two line to two holes

as beginner, thanks to tkaiser for configure guide, now we can use this usb port. because it directly to H3 without any protective device, use it should be as careful as possible.


#15

I tried to add this information to linux-sunxi wiki since this subforum seems to be even more dead than the others and as usual SinoVoip doesn’t provide correct documentation (this port is mentioned nowhere, in their chapter about USB OTG M3 and not M2+ is mentioned – so as usual you never know whether this is correct or just the usual copy&paste errors they’re so famous for)

@sinovoip: Do you get the idea why providing correct documentation might matter?

@sinovoip: Care to update your wrong schematic (1.3V instead of 1.2V)?

@sinovoip: Do you know why users vanish from these forum? Since you don’t answer even the most simple questions. This is not a community forum since no users are around. The only reason people are posting here is to ask support questions. Like question N°1 above: “Is it possible to power supply BPi-M2+ over header”. Why don’t you answer your user’s questions?

@sinovoip: Do you get the idea why people are not that satisfied? Of course not :slight_smile:


#16

@tkaiser, @BPI_Q many thanks for your research and testing. Without this answers it is hard to imaging that people will choose Banana platforms for further project, not saying about serious prototyping.


#17

But even if 100 others tell them they won’t get the idea that respecting their users and answering such basic questions would be a good idea. It’s no wonder that devices like these might be sold to newbies (since they are uneducated and think the new Bananas would be compatible to the good old ones based an A20) but then only collect dust lying somewhere around due to lack of software or even basic information :slight_smile: