Reading Pendrive using MAX3421

Discussion in 'Embedded Systems and Microcontrollers' started by sanju.np, Jul 1, 2011.

  1. sanju.np

    Thread Starter New Member

    Jul 1, 2011
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    0
    Sir,
    Please help in reading the pen drive data using MAX3421 IC.
    I am struggling hard to getting an idea. I went through the datasheet but its quite confusing...
    I just know that if I want to read data from Pen drive. I have to interface my mc to MAX3421 and have to give some command. But what should be the command???
    What is for GPIN and GPOUT???

    Please sir... please somebody guide me....

    Thank u in advance...
     
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,386
    1,605
    I haven't used this chip but it is an interesting device. I like the simplicity of bus isolation with this device.

    Looks like it can work as a USB host too, so it can control your pendrive. Do take a look at the programming guide and code walk their sample application.

    THE "GP" pins are general purpose pins, you get extra IO with them. You need to live with this documentation till it is in your bloodstream or you will not get this thing to work.
     
  3. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
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    Firstly, you need to enumerate the device over the control endpoint. Have you successfully done this?
     
  4. sanju.np

    Thread Starter New Member

    Jul 1, 2011
    2
    0
    Thank u very much for ur kind interest in helping me.

    Sir, I didnt get u actually... Enumerate the device over the control endpoints???

    I just know that the device support spi and the datas to the pendrive are written as packets... but how it is possible through max3421... what all things i have to configure in that using the mc...
     
  5. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
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    correct me if I'm wrong, but I believe that in referring to a pendrive, your talking about a flash memory interfaced via USB protocol.

    The max3421 is typically implemented due to it's USB hosting capabilities, and would act as such to communicate with the drive, likely using the mass storage protocol. The max3421 in itself has no storage capacity, so would transfer USB data to a micro. The micro to max interface is done over SPI.

    To implement a working USB communication channel, you must first initialize the max3421. You are now ready to communicate with the attached USB device. All devices must be enumerated. Although enumeration can contain information gathering (getdeviceinfo), in it's simpliest form, it selects the devices mode of operation.

    Once enumerated, you would then access the drive data over the bulk endpoints.

    Configuring the max3421 is relatively easy. One sticky point that I had to work through was the data toggle, but once done it's done.

    The real time investment is in understanding the USB protocol, so I suggest that you read the various protocols that you'll be implementing.
     
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