I want to buy jetson tk1, but I have a few questions.

Hi all!

I want to replace original vending machine controller with some embedded system (like tk1), but I have a few questions before make a decision before buy a particular controller.

  1. It should has pins to connect to the mdb protocol: http://en.wikipedia.org/wiki/Multidrop_bus & other stuff through gpio.
  2. Good performance. There will be a display with browser showing rails application running. I’ve tried a raspberry pi B+, but it’s too slow (it can’t run even a browser with speed like usual laptop pc).
  3. Custom video output. Sometimes I need to show to display with the FullHD(1920x1080), sometimes I need to show at 768x1024 (yes, the computer should simply rotate video output)
  4. I don’t want to connect microcomputer to display directly, not through HDMI, DVI or something like this. I prefer DSI connection (This is not required, but very desirable).

Does these requirements fits to jetson tk1?
What can you say me about it?

Thanks in advance,
Alex

P.S. Duplication of this question at robotics.stackoverflow: http://robotics.stackexchange.com/quest … the-board/

I’m pretty sure Jetson has no support of any kind for mdb protocol. You would have to add all electrical compatibility required, such as level shifters, along with all software from the driver on up.

Jetson has extreme performance, you’ll probably find it is overkill. The GPU available for CUDA does require special programming to take advantage of it, but everything else in terms of CPU and audio/video are the best you’ll find in a 32 bit package.

The HDMI output requires a monitor with EDID capability and no adaptor cutting that availability. E.G., an analogue 15 pin VGA to HDMI adaptor would force manual video configuration. Behaviour of video is dependent upon the linux software used rather than Jetson; Jetson itself has no detection of acceleration or orientation so if you wanted to tie this in it’d all be manual addition.

You’ll find non-HDMI output possible but something of a difficult issue and a learning curve is required.

Thanks for answer!

I want to know about this

I understand that jetson will require few software changes, but why do I need extra electrical level shifters? Here is example of arduino code, which works just with optocouplers:
http://blog.bouni.de/blog/2012/05/06/the-mdb-protocol-part-1/
http://blog.bouni.de/blog/2012/07/09/the-mdb-protocol-part-2/
http://blog.bouni.de/blog/2012/07/11/the-mdb-protocol-part-3/

Why can’t I use jetson the same way, just by serials connected through transistors?

Is there any pins for that?
Alex

Some of the Jetson I/O (GPIO, serial UART) is 1.8V, some 3.3V, some 5V. It just depends which I/O you are connecting through, along with what your external machine uses (or your opto coupler). Most of this depends on the pull-up present on the pm375 board which the tegra chip sits on…even if the tegra124 is listed as supporting various voltages, you have to live with what this board is configured for (unless you want to somehow modify the board itself…level shifters are just easier, I have no idea what your opto couplers support). The 9600 bps 9N1 is quite slow and Jetson will have no issue with this, but there is no software installed which specifically understands your protocol.

There are several threads devoted to HDMI and alternative displays. You’ll have to just dig around to see how many issues there are. When reading those beware that you need the DDC/EDID channel if you are to randomly remove and add displays and have them “just work” without telling the system what is connected. There are many connector pins devoted to CSI/DSI/LVDS, but it is the EDID which tells the Jetson what is currently attached…if your display does not have this you will have to add it or else manually configure for each monitor and tell it which monitor is attached…HDMI simplifies this, other custom display interfaces complicate this.

linuxdev,

thanks for the answer!
Just one question. It seems I need two uarts for my development needs. Does tk1 can offer me 2 uart gpio?

There’s one uart in the expansion header marked for generic use and one marked as “nvidia only”. There is also a lot of other pins and it might be possible to remap some of those to have a second uart. You would need to check from the TRM, if that’s possible though.

A lot of HW related info is available here:
https://developer.nvidia.com/hardware-design-and-development

What is TRM?

How can I check the possibility to implement second uart on other pins?

Technical Reference Manual.

FYI, check here for this URL:
https://devtalk.nvidia.com/default/topic/793798/embedded-systems/some-jetson-web-links/