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USB Programming — Parallax Forums

USB Programming

jmwachteljmwachtel Posts: 12
edited 2011-02-11 08:57 in Propeller 1
I have some questions regarding the propeller chip. I want to implement a USB interface to allow the chip to be reprogrammed at will. What is involved in doing this? I see that I could make a Prop Clip and integrate it into my board, which I am interested in doing, or buy the clip. I also plan to buy the 40 pin Propeller DIP chip, 5 MHz crystal, and 64KB EEPROM chip. Does the 64KB EEPROM have to be initially programmed? I do not have an EVAL board, and I am trying to avoid having to buy one. I would like all the programming to done through USB. Any guides on how to do this?

Thank you,
Joseph

Comments

  • LeonLeon Posts: 7,620
    edited 2011-02-11 07:05
    You don't have to program the EEPROM initially, to get started. You don't even need it, especially when testing, as code can be loaded directly into the Propeller.
  • SapiehaSapieha Posts: 2,964
    edited 2011-02-11 07:05
    Hi jmwachtel. You only need some USB to Serial interface that have /Reset of propeller implemented. For functioning Propeller need only 32KB EEProm But can have bigger one that Uper part You can use to other things. You not need any EVAL board -- Propeller NOT need preprogrammed EEProm to. For Propeller to function as Evaluating Board and If You wish YOU not even need EEProm to test Yours Programs.
    jmwachtel wrote: »
    I have some questions regarding the propeller chip. I want to implement a USB interface to allow the chip to be reprogrammed at will. What is involved in doing this? I see that I could make a Prop Clip and integrate it into my board, which I am interested in doing, or buy the clip. I also plan to buy the 40 pin Propeller DIP chip, 5 MHz crystal, and 64KB EEPROM chip. Does the 64KB EEPROM have to be initially programmed? I do not have an EVAL board, and I am trying to avoid having to buy one. I would like all the programming to done through USB. Any guides on how to do this?

    Thank you,
    Joseph
  • jmwachteljmwachtel Posts: 12
    edited 2011-02-11 07:08
    Okay great, so no boot-loader is needed? As soon as I attached the FTDI chip/USB Mini connector to the propeller chip, I could start programming for it right away?
  • SapiehaSapieha Posts: 2,964
    edited 2011-02-11 07:12
    Hi jmwachtel. Yes and NO. You need FTDI interface that have one extra Feature --- /Reset of Propeller. NO and boot loader That one are already in Propeller Tools that You need download from Parallax.
    jmwachtel wrote: »
    Okay great, so no boot-loader is needed? As soon as I attached the FTDI chip/USB Mini connector to the propeller chip, I could start programming for it right away?
  • jmwachteljmwachtel Posts: 12
    edited 2011-02-11 07:17
    Still confused then, what do you mean by yes and no? Are there any procedures on how to do this?
  • SapiehaSapieha Posts: 2,964
    edited 2011-02-11 07:25
    Hi jmwachtel. Yes if You use PropPlug that are designed for Propeller. NO if You build Yours FTDI Interface and not build it in that WAY Schematics In Propeller Tools describe. If You download Propeller Tools --- IN Help menu You can find most info on that. You can even LOOK on Sticky threads. http://forums.parallax.com/showthread.php?111166-Propeller-HYDRA-Key-Thread-Index http://forums.parallax.com/showthread.php?89958-Propeller-Education-Kit-Labs-Tools-and-Applications
    jmwachtel wrote: »
    Still confused then, what do you mean by yes and no? Are there any procedures on how to do this?
  • jmwachteljmwachtel Posts: 12
    edited 2011-02-11 07:52
    I am planning on implementing it as shown in the PropClip schematic. Does anyone know what kind of NPN transistor to use? This transistor is used as a switch in this circuit, correct?
  • LeonLeon Posts: 7,620
    edited 2011-02-11 08:31
    Virtually anything should work, such as a 2N3904 or a BC182.
  • jmwachteljmwachtel Posts: 12
    edited 2011-02-11 08:34
    Is it used as a switch?
  • LeonLeon Posts: 7,620
    edited 2011-02-11 08:43
    Yes, it is.
  • tonyp12tonyp12 Posts: 1,951
    edited 2011-02-11 08:49
    You could also use the new MCP2200 chip.
    at least it comes in SOIC version that is easier to reflow solder by hobbiest.
  • Mike GreenMike Green Posts: 23,101
    edited 2011-02-11 08:57
    For some programming, you don't need a crystal either. The Propeller has an internal clock that's used initially and runs somewhere between 12MHz and 20MHz. It's not accurate and tends to drift with temperature and supply voltage which is why you need a crystal for anything requiring accurate timing (like asynchronous serial I/O or video). The bootloader in ROM uses a self-timing protocol that gets around this inaccuracy.

    Look at the Propeller Education Kit (PEK) tutorials for examples of minimal Prop circuitry on a breadboard. One of the "sticky threads" on this forum has links to all the PEK stuff.
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