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Is it possible to directly connect the Prop. to USB without USB to Serial circuit? — Parallax Forums

Is it possible to directly connect the Prop. to USB without USB to Serial circuit?

lyassalyassa Posts: 52
edited 2011-12-31 19:50 in Propeller 1
I always thought that the USB-to-Serial is to maintain backward compatibility? Is that right? Is it possible to have the Propeller talk to the USB port straight without going through FTDI 232?

Comments

  • Clock LoopClock Loop Posts: 2,069
    edited 2011-12-26 18:07
    • USB emulation with the Propeller
    http://forums.parallax.com/showthread.php?135387-USB-emulation-with-the-Propeller&highlight=usb+toys+play



    • USB toys to play with
    http://forums.parallax.com/showthread.php?97328-USB-toys-to-play-with&p=881846&viewfull=1#post881846
  • lyassalyassa Posts: 52
    edited 2011-12-31 10:15
    Thanks Clock Loop. The circuit and the code - by Brad C - from the second link in your answer works beautifully. As soon as I connect it to the USB port, it sends some lyrics to a text editor on the PC. However, the demo file "USB_California_005.spin" is more than 600 lines of assembly code, and I am having hard time figuring out how to use the code for my purposes. Basically just reading the status of some input pins (high or low) and reporting that to the PC. Any help is greatly appreciated.
  • Cluso99Cluso99 Posts: 18,069
    edited 2011-12-31 12:02
    lyassa: I presume you do not want to use the USB emulation within the prop to download code??

    scanlime (micah) also did some work on USB although IIRC it was all master implementation (ie connects to a USB device such as a bluetooth dongle). Try searching the forum for USB Bluetooth or similar. It was some time ago.
  • lyassalyassa Posts: 52
    edited 2011-12-31 14:44
    Hi Cluso99,

    Hmmm .. USB emulation within the Prop? Do you mean the USB-to-Serial plug to download code to the eeprom?

    I am ok using the usb-to-serial to download code from the development tool to the eeprom, but then I want to be able to remove the usb2ser plug and directly connect the Propeller to USB as descibed in the link "USB toys to play with" above.

    I guess I am not sure what is the "USB emulation within the prop". Please direct me to where I can find more info; if it is not the usb2ser plug. Also, at this point I don't need the Propeller to host USB, rather the PC will be the master and it will host the Prop.
  • Cluso99Cluso99 Posts: 18,069
    edited 2011-12-31 18:43
    lyassa: I think you get what I meant. Use the propplug (usbser) to program the eeprom (download), then remove.

    There are two people who have done software USB emulation on the prop. Bradc which you have seen ( slave) and is LS (low speed) and Micah/scanlime who has done IIRC both master an slave. Micah got HS to work using 4 cogs!! but it is not compliant.

    The prop does not have the required hardware to do a totally compliant USB (anyone want to take the bait and do it?? - sorry lyassa... its an in joke... it was once said that the prop could not do USB at all, and many other things. Someone always wants to prove us wrong here and go do it!)

    Anyway, here is the link to scanlime's thread where you can see what she's done http://forums.parallax.com/showthread.php?121321-Working-full-speed-(12-Mb-s)-bit-banging-USB-Host-controller&highlight=scanlime+usb+bluetooth
  • LeonLeon Posts: 7,620
    edited 2011-12-31 19:27
    You mean full-speed, not high-speed USB. High-speed USB (480 Mbit/s) really is impossible on the Propeller.
  • Cluso99Cluso99 Posts: 18,069
    edited 2011-12-31 19:50
    Thanks Leon, yes my mistake.
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