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by ali1234
Wed Nov 22, 2017 8:17 pm
Forum: Advanced users
Topic: MTP responder with functionfs
Replies: 4
Views: 1979

Re: MTP responder with functionfs

I have also been trying to do this.

I am not using buteo or the Ubuntu mtp responder, but instead writing my own from scratch in python. It does not need any android kernel patches etc.

It doesn't work yet but it is getting close.

https://github.com/ali1234/pymtpd
by ali1234
Tue Jun 13, 2017 2:53 pm
Forum: Official Foundation Display
Topic: V1.0 has brightness control
Replies: 14
Views: 4538

Re: V1.0 has brightness control

That would work I suppose. You need to put the jumper wire in too.
by ali1234
Wed Aug 17, 2016 11:30 am
Forum: Official Foundation Display
Topic: V1.0 has brightness control
Replies: 14
Views: 4538

Re: V1.0 has brightness control

It kills the boost converter eventually.
by ali1234
Mon Aug 15, 2016 2:03 pm
Forum: Official Foundation Display
Topic: V1.0 has brightness control
Replies: 14
Views: 4538

Re: V1.0 has brightness control

I had the hardware mod made at oshpark. Works like a charm.

http://imgur.com/a/6rdaD
by ali1234
Wed Aug 03, 2016 7:11 pm
Forum: Official Foundation Display
Topic: V1.0 has brightness control
Replies: 14
Views: 4538

Re: V1.0 has brightness control

If you are brave enough it would be possible to desolder U1, R4, R5, R6, and then drop in a tiny replacement board:

Image

"X" needs a jumper wire to PP19.

edit: you also need to reflash the AVR chip to the V1.1 firmware.
by ali1234
Sun Jul 31, 2016 12:27 am
Forum: Official Foundation Display
Topic: V1.0 has brightness control
Replies: 14
Views: 4538

Re: V1.0 has brightness control

Okay I finally got to the bottom of this. First I reverse engineered the circuits: http://imgur.com/a/24TFn Then I found the datasheet for the backlight driver chip: http://www.onsemi.com/pub_link/Collateral/CAT4139-D.PDF Marking code indicates it is the same chip in V1.0 and V1.1. There are two dif...
by ali1234
Sat Jul 30, 2016 4:58 pm
Forum: Official Foundation Display
Topic: CE compliance for RPi + Pi Display?
Replies: 12
Views: 2772

Re: CE compliance for RPi + Pi Display?

I have not been able to determine the part number for the driver chip, but I have reverse engineered the circuit. It is a boost converter, switching at 975kHz in the V1.1 display. There is also an interesting anomaly in that the driver in the V1.0 either has a non-standard pin out, or the board has...
by ali1234
Tue Jul 26, 2016 5:54 pm
Forum: Official Foundation Display
Topic: V1.0 has brightness control
Replies: 14
Views: 4538

V1.0 has brightness control

Today I reverse engineered the I2C backlight control protocol and I found something very interesting. The V1.0 display supports 256 levels of brightness control. It's just the Pi firmware which prevents you from using anything other than full on and full off. If you connect the display to your own I...
by ali1234
Thu May 12, 2016 1:31 pm
Forum: General discussion
Topic: 3G Modem Doesn't Create /dev/ttyUSB*
Replies: 3
Views: 1264

Re: 3G Modem Doesn't Create /dev/ttyUSB*

These modems often initially present themselves as a USB flash drive containing Windows drivers and software. The presence of sd/sg devices indicates that is what is happening here. The USB IDs are a red herring. As the poster above said, you need usb-modeswitch to reconfigure it in normal mode.
by ali1234
Wed Apr 13, 2016 6:07 am
Forum: General discussion
Topic: PiZero Roadmap
Replies: 159
Views: 60384

Re: PiZero Roadmap

Will the USB test points be in the same place?
by ali1234
Wed Jan 13, 2016 8:23 pm
Forum: Advanced users
Topic: HOWTO: Enable USB device mode on Pi Zero
Replies: 68
Views: 42888

Re: HOWTO: Enable USB device mode on Pi Zero

Buildroot was successful for me with the following: git clone git://github.com/raspberrypi/tools git clone git://git.buildroot.net/buildroot cd buildroot git checkout 7d37754113e9c689b2a617ceb227dbd3a0135726 patch -p1 < ../tools/usbboot/buildroot.patch chmod a+x board/raspberrypi/usb_test/post_build...
by ali1234
Tue Jan 05, 2016 1:32 pm
Forum: Advanced users
Topic: HOWTO: Enable USB device mode on Pi Zero
Replies: 68
Views: 42888

Re: HOWTO: Enable USB device mode on Pi Zero

On a side note, I've tried a couple of times to build the linux buildroot image as per https://github.com/raspberrypi/tools/tree/master/usbboot but failed. Have you had any joy with that? I built it before ages ago on Ubuntu and then booted it on an A+. I didn't have any problems doing so, but as s...
by ali1234
Tue Jan 05, 2016 1:54 am
Forum: Advanced users
Topic: HOWTO: Enable USB device mode on Pi Zero
Replies: 68
Views: 42888

Re: HOWTO: Enable USB device mode on Pi Zero

For the people trying to use usbboot, here is a quick and dirty hack to get it working. You need to give it a FAT filesystem image with kernel.img, start.elf etc. The same stuff you would find on /boot. You can put a Linux kernel image and initrd in it. That is what the buildroot does. However, the ...

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