Ben NanoNote Production Process

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Contents

[edit] Component sourcing

[edit] PCB

[edit] SMT

[edit] COB

[edit] Assembly and Testing

TBD: There are many more steps that are not described yet.

Battery testing
FPC hotpress
Removing the LCM protective film.
Cleaning the PC Sheet.
Cleaning the LCM.
Positioning the keyboard layer.



[edit] Reflashing

Flashing Ben NanoNotes (note the ubiformat error on the one in the background).
  • boot via Jz4720 USB boot feature
  • usbboot -c "boot;nerase 0 4096 0 0; nprog 0 openwrt-xburst-u-boot.bin 0 0 -n; nprog 1024 openwrt-xburst-uImage.bin 0 0 -n"
  • reboot, press 'm' to boot from microSD
  • run 'ubiformat /dev/mtd2 -e 0 -f openwrt-xburst-rootfs.ubi'
  • reboot from NAND, turn off
Example of good (top) and bad (bottom) USB cable. The bad thinner cable at the bottom gave us a lot of "unable to enumerate USB device" and "can't read bulk data from Ingenic device" errors when flashing u-boot and kernel. Eventually we found out that this cable lost voltage over time! Right after connecting, we measured 5.0V, then with this cable voltage slowly went down and after about 30 seconds was already at 4.75V [TBD: any theories on why that is happening?]. We threw away the bad USB cable. Lesson learnt: There are really bad USB cables out there, watch they may send you in the wrong direction and waste your time...
MicroSD cards used for reflashing.
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