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Can I connect any of Logi to UDOO platform?

mhdanasmhdanas
in LOGI General Discussion
i have both the LOGI PI and LOGI Bone since some time i'm looking to connect it with UDOO since i have it and  it's more powerful platform and as i don't have any of the raspberry or Beaglebone , just i don't know how complex to support it as it have different possessor and may need some kernel module modifying.... did any one try it ?!
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Comments

  • mjonesmjones
    Hi @mhdanas,

    The are not designed specifically for the UDOO board, but there are a number of ways that you could get it to work.  

    I have not looked the communcation options that the I.MX6 has: SPI, GPMC as is on the Pi or bone?  

    SPI would be the best place to start as it is a simple protocol and once you get the drivers running on the UDOO you could then use the existing LOGI wishbone architecture and drivers to communication between the FPGA and UDOO.  

    One option that you could do have the LOGI directly fit the UDOO woudl be to remove the standard arduino headers on the LOGI board and replace them with the extended shield arduino header so that you could plug the LOGI dirctly into the UDOO board.  

    We are looking into future platforms that would be well suited for the LOGI boards, so feel free to give us suggestion such as this.


  • mhdanasmhdanas
    thank you for ur reply,well as i saw in logi documentation spi speed limited to 4MB or so while it could be 69mb by GPMC..... anyway udoo have more than one SPI is it possible to have it work together? or it need more complex wrapper  ?..., and what i need to modify with the UDOO image to get it just work fine....?
  • mhdanasmhdanas
    forget to say that udoo have 5V logic level so i think we need to have level shifter to do connection as you said with arduino headers..right ?
  • mjonesmjones
    Hi @mhdanas

    Sure you could use both SPI ports, but you would need to create a timing sync between the 2 signals which could be a bit tricky.  

    Based on this udoo page the Arduino port does not connect directly to the I.MX processor, but to an actual Sam3x atmel chip onboard.  So unless you wanted to connect the FPGA to the Sam3X chip you there would not be much reason to stack the LOGI onto the Arduino Shield.  Also, the documenation states that the ARduino logic is 3v3 volt rather than 5V.

    Hope this helps,
    Mike
  • mhdanasmhdanas
    Well about SPI time sync this on the IMX6 side i think you are right...
     
    About arduino port Well... actually both processor are connected to arduino port
     so i could connect it to I.MX6 and this what i'm looking for... i want it to connect to Linux with fastest connection could be handled without getting jammed in some complex "writing driver" for now.. anyway even that I.MX6 connected, we still need pinmuxing as udoo default use I.MX6 pinout like GPIO and loading kernel driver for SPI i'm still reading about it, just do you think fastest "possible" connection is via SPI..?, and what stuff that i need to loaded to Linux on UDOO to make it work as perfect as on RPI or BBB with much better processing and connectivity that I.MX6 can add..
  • jpiatjpiat
    Hi,

    if the main advantage you see in the UDOO platform is the IMX6, you should consider using http://www.solid-run.com/products/hummingboard/ as its expansion port is pin compatible with the raspberry-Pi and should play well with the LOGI-Pi. Another alternative if you want more processing power and have the ability to connect a LOGI platform is the odroid C1 that had a quad-core ARM processor and a 40pin expansion port compatible with the B+.

    The faster communication over SPI only depends on the max frequency of the SPI controller of your platform. For example the Raspberry-pi can go as high as 48MHz (~ 40Mbit/s) and the BBB can achieve the same speed. Some SPI controller may work at higher freq but depending on the routing of the signal to the connector, you may not be able to work at the highest avalable freq. Another factor that can slow down the communication is the processor speed and the use of DMA for SPI. The processor speed will affect the time between the a transaction is started on the user side and the actual start of the communication (same thing of the end of the communication)  on the bus. The use of DMA (not available on all cores) will allow the memory transfer to happen in parallel with the communication, while a non-DMA implementation will take some time between each word read/write on the bus. For example at the exact same clock speed, the SPI controller of the raspberry-pi seems to be more efficient than the one of the BBB (spi communication on the raspberry-pi is closest to the theoretical speed than what the BBB achieve).

    Regards,

    Jonathan Piat
  • mhdanasmhdanas
    Hi jpiat ,

    well UDOO have more than just IMX6 with quad processing, wifi, those too much input output and using sata storge in compact place non of those could do....+i already have it :)

    about connection you are right just as i read in the documentation

    Raspberry Pi SPI to FPGA Interface

    The Raspberry Pi to FPGA main communication interface is the PI SPI port.  The Max stable SPI clock rate that has been tested is 32-48Mhz.  Based on our development experience there are some instability issues that can occur when using higher clock rates.  By default the current LOGI SPI drivers runs at 48 Mhz  With the current 48Mhz clock and direct communication to the FPGA the user can expect to get 4 MB/S throughput between the Raspberry Pi and the FPGA. 


    while the GPMC on BBB is 

    Current GPMC performance with the LOGI Drivers

    The current LOGI GPMC drivers have a theoretical bandwidth of 76MB/s and measured up to 69MB/s in user space for transfer of 128KB blocks


    so if we are talking about logi connectivity i think BBB with it GPMC  faster 15 time more than RPI with SPI so i was asking if there is any possible way to make faster connection with UDOO other than SPI 

    Regards,

    Anas 

  • jpiatjpiat
    You can sure get a faster connection by wiring a parallel bus between the UDOO and the LOGI-Board, but this parallel bus will have to be managed in software (bit-banged bus) if your processor does not have an external memory bus (i haven't digg into UDOO documentation but there is little chance it has one exposed on the connectors).

    The GPMC on the BBB is an external parallel memory interface @50Mhz with DMA (Direct Memory Access) hence the 15x speed-up over SPI ...
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