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USB Expander and Debug Add-On Board User Guide

Table of contents

  1. Summary
  2. Board Connections
  3. Specification
  4. USB2 Host Pinout
  5. Connecting to VOXL
  6. Connecting a USB2 Peripheral
  7. Forcing the VOXL into Fastboot to Unbrick
  8. Using the Debug Console
  9. Forcing the VOXL into Emergency Boot

Summary

The VOXL USB Expander and Debug Add-On board provides:

  • Ability to connect an additional USB2 peripheral device to VOXL
  • A debug console for low level system debugging
  • A switch that will force VOXL to boot into fastboot mode (for reflashing the System Image if the unit is bricked in the field)
  • A switch that will force VOXL to boot into emergency boot mode (used at the factory only)
    • NOTE: newer versions of the board don’t have this switch populated

Board Connections

voxl-usb-expander-and-debug.png

Specification

SpecicifcationValue
Weight5g
Debug Console ConnectorMicro USB, Female
Debug Console Mating ConnectorMicro USB, Male
USB2 Host Connector4 Position JST GH, Vertical, BM04B-GHS-TBT
USB2 Host Mating ConnectorJST GHR-04V-S
J1 ConnectorSamtec Inc, MPN: QTH-030-01-F-D-K
J1 Mating ConnectorSamtec Inc., MPN: QSH-030-01-L-D-A-K

USB2 Host Pinout

Pin 1 is marked in the Board Connections graphic above.

PinValue
1VBUS
2USB_M
3USB_P
4GND

Connecting to VOXL

To connect the USB Expander and Debug Add-On board to VOXL:

  • Attach the daughter board’s J1 connector to VOXL’s J13 connector

voxl-usb-expander-and-debug-connected.png

Connecting a USB2 Peripheral

A USB2 peripheral can be connected via a JST GHR-04V-S connector following the pinouts specified in the datasheet.

To validate the connection:

  • Power off the VOXL
  • Attach the USB Expander and Debug Add-On board
  • Ensure the FASTBOOT labeled switch is set to off
  • Ensure the EMERG BOOT labeled switch is set to off
    • NOTE: if your board is missing the EMERG BOOT switch, this is OK as its default un-populated state is OFF
  • Attach the USB2 peripheral
  • Power on the VOXL
  • Connect a Micro USB cable to VOXL’s USB port and connect to a Linux PC

Open the terminal in the Linux PC and run the following:

adb shell

Now you’re inside VOXL, run the following, where in this use case we’ve attached a Flight Core board to the USB2 Host connector (showing up as the STMicroelectronics MCU):

/ # lsusb
...
Bus 001 Device 003: ID 0483:a32f STMicroelectronics
...

Forcing the VOXL into Fastboot to Unbrick

Follow the unbrick procedure found at docs.modalai.com/unbrick-voxl

Using the Debug Console

You’ll need two MicroUSB cables for this procedure.

  • Power off the VOXL
  • Attach the USB Expander and Debug Add-On board
  • Ensure the FASTBOOT labeled switch is set to off
  • Ensure the EMERG BOOT labeled switch is set to off
  • Connect a Micro USB cable to VOXL’s USB port and connect to a Linux PC
  • Connect a second Micro USB cable to the Add-On board’s Micro USB port and connect to a Linux PC. It may display as FT232R USB UART and will exist as /dev/ttyUSB0
  • Power on the VOXL

Open Terminal A in the Linux PC and run the following command (if screen isn’t installed, first run apt install screen):

screen /dev/ttyUSB0 115200
[HIT ENTER]

Open Terminal B in the Linux PC and run the following commands:

adb shell
reboot

You should now see debug information in Terminal A:

[10] Opening SSR Glink Port success
[20] Glink Connection between APPS and RPM established
[20] Glink Connection between APPS and RPM established
[40] UFS init success
[80] pm8x41_get_is_cold_boot: cold boot
[90] Unable to locate /bootselect partition
[90] Loading (boot) image (57376768): start
[300] Loading (boot) image (57376768): done
[310] use_signed_kernel=1, is_unlocked=1, is_tampered=0.
[310] decompressing kernel image: start
[630] decompressing kernel image: done
[640] Best match DTB tags 291/00000008/0x00000003/30001/20009/10013/0/0/940319e2/51297
[650] Using pmic info 0x20009/0x10013/0x0/0x0 for device 0x20009/0x10113/0x0/0x0
[650] cmdline: noinitrd rw console=ttyHSL0,115200,n8 androidboot.hardware=qcom ehci-hcd.park=3 msm_rtb.filter=0x37 lpm_levels.sleep_disabled=0 rootwait net.ifnames=0 androidboot.bootdevice=624000.ufshc androidboot.serialno=a0259b4a androidboot.baseband=apq root[670] Updating device tree: start
[680] Updating device tree: done
[680] RPM GLINK UnInit
[690] booting linux @ 0x80080000, ramdisk @ 0x82200000 (0), tags/device tree @ 0x82000000
[690] Jumping to kernel via monitor

Forcing the VOXL into Emergency Boot

This is typically done at the factory and not in the field by a normal user. To force the VOXL to boot into emergency boot mode:

  • Power off the VOXL
  • Attach the USB Expander and Debug Add-On board
  • Ensure the FASTBOOT labeled switch is set to off
  • Ensure the EMERG BOOT labeled switch is set to on
  • Attach
  • Power on the VOXL

The device will show up on a Linux PC as Qualcomm, Inc. Gobi Wireless Modem:

/ lsusb
...
Bus 001 Device 015: ID 05c6:9008 Qualcomm, Inc. Gobi Wireless Modem (QDL mode)
...


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