Thursday, July 18, 2013

txtr Beagle teardown

As you might now the txtr Beagle is the new kid on the block: the cheapest and lightest ebook reader around. Or at least that's what the marketing says.
I bought mine for around 20E, which is quite a bit more than the 10-13 EUR they were aiming for. I guess that's the price one must pay to stay on top of technology.
The main reason I bought one was to have some kind of remote display for use for example as a wall clock, To-Do board or bike GPS readout.

Video:
http://youtu.be/KTEGRSdxxxg

Part 1: http://hackcorrelation.blogspot.de/2013/07/txtr-beagle-teardown-part-1.html

Part 2: http://hackcorrelation.blogspot.de/2013/07/txtr-beagle-part-two-software.html

Part 3: http://hackcorrelation.blogspot.de/2013/07/txtr-beagle-part-3-storage-and-transfer.html

Part 4: http://hackcorellation.blogspot.de/2013/07/txtr-beagle-card-parser.html

Part 5: http://hackcorrelation.blogspot.de/2013/07/txtr-beagle-native-code-analysis.html

It's a bit hard to take apart since everything is glued together. There are two TR5 screws but they serve no other reason than to annoy.

First, some information on how it's supposed to work:
  • - you bind the reader via bluetooth to a phone or tablet
  • - you download the book on the phone, set the font size and upload it to the reader
  • - each subsequent font change requires reuploading the book
  • - the reader can only hold 5 books, though it's supposed to have 4GB of memory
  • - one-year battery life on two AAA cells

It's obvious that the books are pre-rendered on the phone prior to being uploaded because it takes about 2-5 minutes to upload a text-only book and the reader has instant start-up, so no parsing is involved.
Before tearing it down I assumed a low-cost ARM processor, some soldered down flash memory, a common bluetooth chip and the eInk controller along with the usual host of auxiliary components: DC-DC converters, breakout and testing pads, perhaps some level translators.

Inside there is a bit of surprise: a microSD flash card along with its socket. I can't imagine how this is cheaper than just soldering a flash chip, but there you go.


My assumptions seemed to be correct, there is low-cost LPC ARM Cortex M3 uC, no RAM chips, the 4GB card raw image compresses to 40MB.



Chips


  • TPS65181 - Texas Instruments eInk voltage driver
  • MAX1763 - 1.5A DC-DC step-up converter
  • AC253M - TI dual 4-input multiplexer with tristate outputs
  • AC86M - TI quad XOR gate
  • KRGA5000 / F12335338 - custom branded txtr ASIC; probably eInk signal driver
  • LPC1313F - NXP 32-bit ARM Cortex-M3 (up to 32 kB flash and 8 kB SRAM; USB)
  • BC417 - CSR single-chip Bluetooth v2.0+EDR (2-3Mbps); USB and dual UART ports
  • M29W800DB - Micron 8-Mbit flash

The flash memory is presumably there for the Bluetooth chip.

SDCARD

I've plugged the microSD card into a Kali VMWare instance and ran ddrescue on it. Everything looks like a lot of repeated data similar to what a BMP file looks like. I see no obvious file table so it's probably just a raw file format with possibly some indexing.
On my reader, even though I've filled all 5 books, only 10% of the card seems to be used, that means 400 MBytes. Nevertheless, the complete file gzip compresses to around 40MB. There are no obvious readable texts and it also does not look like any compression or encryption is involved.
The brand is Sandisk, class 4, I got a constant bulk reading rate of around 10 MBps.


Test pads

Unfortunately there are no visible UART pads so this might be harder than I expected. There are just breakouts for Bluetooth SPI, SD card SPI, JTAG and battery.

Conclusion and further developments

I'm uploading a teardown video on Youtube right now but it seems to take forever at 600kbits/s. Actually, it's several videos that need to be somehow combined, so watch this space to see when they come up.
Since this is my first time doing a teardown video I might not like how it turned out and it might never be listed here.

I don't have much spare time but I'll try to analyse the SDCARD contents and see if I can get some UART data out of the bluetooth chip.

I was expecting to see a lot of low-cost stuff in there but they obviously went with volume. I have absolutely no idea how the volume pricing goes but to me this looks to be around 10$ in parts for a 2M volume.

Edit 02 Aug 2013: I was not aware that eInk displays have not gone down significantly in price. I still stand by my initial 10-15$ estimation (not including NRE costs like tooling) but the electrophoretic displays still cost more than 20$.
So it looks like the initial units were sold at a loss which is in line with the announced 60% price reduction. I very much doubt they will sell for 20E again unless they are dumping the stock or have found a magical way to make money off of them.

6 comments:

  1. Hi

    you can connect the device to your computer (Mac in my case) via bluetooth and you will find it listed as an Serial device. Using Arduino Software (yeah I know I could have used a cmdline tool...) you can send commands like "HELP" which will list available commands or INFO etc. basicly it gave me info on the device and a list of the books on the device... I did not find the way book-transfer works.

    Moritz

    PS you need to send a line break after the commands!

    ReplyDelete
  2. Since one week I also own beagle... Hope I could hack it with your tutorial and use it as "normal" pdf-Reader or as clock or what-ever. I jsu want to get rid of the stupid txtr app.

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  3. can you upload more than 5 books and what will happen if we can?

    ReplyDelete
  4. Probably yes, try it :)
    Mine is broken, I'm watching the ebay for another one but they are as rare as hen's teeth

    ReplyDelete
  5. Unfortunately, I have no idea how to do it :)
    I want to buy more but stopped them from selling and not give information when it will start up again. : (

    ReplyDelete