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???
03/16/05 21:58
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Msg Score: +1
 +1 Good Answer/Helpful
#89813 - USB ???
Responding to: ???'s previous message
Neil Kurzman said:
How fast are you talking about USB (I2C based) goes up 12 Mb/sec.


No way, no how is USB "I2C based." There are a couple of chips that implement the USB serial engine, and these chips talk to a microcontroller over I2C, but that's not the same as "USB (I2C based)."

Two other reasons for not using USB here:

a) USB has one master and multiple targets, which means that one of his micros has to be the USB master and the other is the target. In this case, the two micros can't be "equally important," since there's no way the target device can tell the host that it's got data. The host must poll. And you need to implement a full host stack, which is very complex.

b) If he's balking at any hardware more expensive than some 74xx devices, no way will he be able to do USB -to- USB.

-a



List of 31 messages in thread
TopicAuthorDate
Contemplating multiprocessor            01/01/70 00:00      
   fifo            01/01/70 00:00      
      and also            01/01/70 00:00      
   multiprocessor communication            01/01/70 00:00      
      ACKs            01/01/70 00:00      
      You want it all and you want it for free            01/01/70 00:00      
         Why not HW I2C or SPI            01/01/70 00:00      
            Why not HW I2C or SPI            01/01/70 00:00      
            USB ???            01/01/70 00:00      
               USB !!!            01/01/70 00:00      
                  USB            01/01/70 00:00      
                     You Correct Sir            01/01/70 00:00      
                  USB != I2C            01/01/70 00:00      
                     USB > I2C            01/01/70 00:00      
         do not multimaster            01/01/70 00:00      
   hmm            01/01/70 00:00      
   concurrence            01/01/70 00:00      
   This is why            01/01/70 00:00      
      depends on data rate            01/01/70 00:00      
   Normally            01/01/70 00:00      
   Are You Sure            01/01/70 00:00      
      I would be            01/01/70 00:00      
         I would be            01/01/70 00:00      
            it works for me            01/01/70 00:00      
      Are You Sure            01/01/70 00:00      
         IIC speed - no limit            01/01/70 00:00      
         nixed by other team members            01/01/70 00:00      
   Multi-Proc Xface            01/01/70 00:00      
      exactly            01/01/70 00:00      
   Shift register (Mode 0)?            01/01/70 00:00      
   Time savers            01/01/70 00:00      

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