svema
Posts: 9
Joined: Sat Jun 20, 2020 10:38 am

Custom IO Board not detecting

Sat Jun 20, 2020 12:09 pm

Hello,

We made a custom IO prototype board.Windows/Cent OS doesn't recognize the board and load the drivers, when in salve boot mode. Here is the snippet of the boot circuit. The only thing that is different from the compute IO board is the USB_OTGID pin, which is connected to GND through a resistor but on our board we did not connect to anything, left it floating. Does this needs to be connected to GND for it to detect on Windows/Cent OS?
Capture.PNG
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Capture1.PNG
Capture1.PNG (57.41 KiB) Viewed 538 times
Thanks,

Santosh

svema
Posts: 9
Joined: Sat Jun 20, 2020 10:38 am

Re: Custom IO Board not detecting

Tue Jun 23, 2020 5:52 pm

Tried connecting the USB_OTGID pin to gnd and still it didnt make a difference.
Other thing is the manual says The USB port (Pins USB DP and USB DM) must be routed as 90 ohm differential PCB traces". Does this affect the board to get detected on Windows/Linux?

gsh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
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Joined: Sat Sep 10, 2011 11:43 am

Re: Custom IO Board not detecting

Wed Jun 24, 2020 3:14 pm

Yes, it's a definite possibility, all bets are off if you've not got the right differential impedance

Does it work when plugged into a Raspberry Pi? I assume it works fine with the CMIO board?

Gordon
--
Gordon Hollingworth PhD
Raspberry Pi - Director of Software Engineering

svema
Posts: 9
Joined: Sat Jun 20, 2020 10:38 am

Re: Custom IO Board not detecting

Thu Jun 25, 2020 3:03 pm

Hello Gordon,

Thanks for your reply. Yes the module works fine when connected to CMIO board.
But it should work in host mode? when I remove the J1 jumper or when the micro-USB is not connected.
When in host mode on CMIO I see:
EMMC_EN_N - 0V
EMMC_Disable_N - 3.3V
No matter if its in host/salve mode (micro-USB connected or not), on our board I see:
EMMC_EN_N - 1.8V
EMMC_Disable_N - 0.6V

Thanks,

Santosh

gsh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
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Re: Custom IO Board not detecting

Tue Jun 30, 2020 11:37 am

I'm not sure what your reply means, "But it should work in host mode?" is that a question or a statement?

What do you mean by host mode in that question? Should Linux enumerate a keyboard when plugged into the board? Yes, as long as R12 is there or you are driving OTG_ID to GND (Although that also depends on which driver you're using, the dwc_otg driver ignores the state of R12 and does host mode anyway). If you want both modes then you'll need to use the dwc2 driver that supports OTG mode.

Or do you mean booting from USB host (mass storage device or ethernet)? In which case it will only work if you've enabled the host boot mode in the OTP and you are correctly setting the OTG pin
--
Gordon Hollingworth PhD
Raspberry Pi - Director of Software Engineering

svema
Posts: 9
Joined: Sat Jun 20, 2020 10:38 am

Re: Custom IO Board not detecting

Tue Jun 30, 2020 2:53 pm

I'm using rpiboot_setup.exe from https://github.com/raspberrypi/usbboot/ ... ster/win32 as the driver under Windows.

Sorry, when I meant host mode, that is when the slave cable is not connected.

I found a problem with my board, the footprints for the MOSFETs were wrong, the drain and source were swapped in the footprint. Once I fixed that, now the PC detects the board and loads the driver. But I get this error when I start rpiboot. While rpiboot is running, if I remove the slave cable and connect again, then it works fine.
rpiboot_error.PNG
rpiboot_error.PNG (27.68 KiB) Viewed 310 times

gsh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
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Joined: Sat Sep 10, 2011 11:43 am

Re: Custom IO Board not detecting

Tue Jun 30, 2020 3:17 pm

I would guess its a signal integrity issue, are you getting this on the CMIO board as well?
--
Gordon Hollingworth PhD
Raspberry Pi - Director of Software Engineering

svema
Posts: 9
Joined: Sat Jun 20, 2020 10:38 am

Re: Custom IO Board not detecting

Tue Jun 30, 2020 8:09 pm

No I don't get this error when using CMIO board. It is only on our custom board.

dp11
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
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Joined: Thu Dec 29, 2011 5:46 pm

Re: Custom IO Board not detecting

Tue Jun 30, 2020 9:25 pm

Which does suggestion a signal integrity issue. Can you share your circuits and PCB layout ? I assume the USB signals are routed as 90Ohm differential pair and length matched?

gsh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 1551
Joined: Sat Sep 10, 2011 11:43 am

Re: Custom IO Board not detecting

Wed Jul 01, 2020 6:20 am

svema wrote:
Tue Jun 23, 2020 5:52 pm
Other thing is the manual says The USB port (Pins USB DP and USB DM) must be routed as 90 ohm differential PCB traces". Does this affect the board to get detected on Windows/Linux?
I'm assuming the traces are thrown randomly onto the board, in which case all bets are off!
--
Gordon Hollingworth PhD
Raspberry Pi - Director of Software Engineering

svema
Posts: 9
Joined: Sat Jun 20, 2020 10:38 am

Re: Custom IO Board not detecting

Thu Jul 02, 2020 7:47 pm

I don't think the length and impedance are matched. But I have the board working now.
I will correct these to match the lengths and impedance in the next prototype version.

dp11
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 74
Joined: Thu Dec 29, 2011 5:46 pm

Re: Custom IO Board not detecting

Thu Jul 02, 2020 7:52 pm

what did you do to fix it ?

svema
Posts: 9
Joined: Sat Jun 20, 2020 10:38 am

Re: Custom IO Board not detecting

Fri Jul 03, 2020 1:09 pm

When rpiboot is running and giving error, then I unplug the USB connector and plug it back, then it works.

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