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why it point out"unknow device"
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why it point out"unknow device"

mrjun posted on 14 Nov 2011 5:33 AM PST
Senior Member
17 Forum Posts

good days to every experienced man,

As the picture showed in follow, EEROM 24LC64 is conectted  to 68013A to keep the firmware .At beginning, i can download my .iic code to EEROM and it worked very well, but as more and more times i powered on and off it, my conputer remind me "unknow device" .when i deconnect the resistance R206, it remind me find USB device and I can download .iic code by console, and then i connect R206,it works well ao before, but i can only keep a while and after powerd on and off a few times again it remain be an "unknow device". i think the most problems happened on EEROM,maybe i should change one, oher way is change c2 renumed to c0 renumed, but maybe there are better solutions,wish your help.




Re: why it point out"unknow device"

PRJI posted on 15 Nov 2011 11:22 PM PST
Cypress Employee
333 Forum Posts


 Hi,

   From your post- it works well without R206 pull up resistor (A0 is directly connected to 3.3V). And also in the data sheet http://ww1.microchip.com/downloads/en/devicedoc/21189f.pdf it says "These inputs (A0,A1,A2) must be connected to either VCC or VSS ". Since data sheet doesn’t require any pull up resistors for Address Inputs why do you use R206???. 

 

Thanks,

Prajith



Re: why it point out"unknow device"

mrjun posted on 16 Nov 2011 04:51 PM PST
Senior Member
17 Forum Posts

hi,

Actualy R206=0Ω , just easy to debug.

I have changed a EEROM IC ,but it still doesn't work.  



Re: why it point out"unknow device"

PRJI posted on 18 Nov 2011 10:09 PM PST
Cypress Employee
333 Forum Posts

  

Hi,

      Please create a customer support case at MyAccount -> MyCases.

Thanks,

Prajith

 



Re: why it point out"unknow device"

aasi posted on 19 Nov 2011 06:55 AM PST
Cypress Employee
1090 Forum Posts

 Following is the reason related to EEPROM that can cause this unknown device pop-up

EEPROM introduces contention on the line by holding SCL or SDA line

Are you violating the supply voltage or VOH, VOL (interfacing 1.8V logic to 3.3V logic etc) rating of the EEPROM in anyway?

Have you tried hooking up a I2C analyzer to check what exactly is happening on the line?

Regards,

Anand

 



Re: why it point out"unknow device"

mrjun posted on 28 Nov 2011 04:43 PM PST
Senior Member
17 Forum Posts

thanks to  aasi, i had find out the questions. when i update my code i forgot to update to configure  EP. but i still not find the basis.



Re: why it point out"unknow device"

aasi posted on 28 Nov 2011 08:54 PM PST
Cypress Employee
1090 Forum Posts

Hi,

Are you saying the unknown device issue got resolved when you configured the endpoints properly?

If so, which endpoint was this and what was the wrong configuration you were using?

Regards,

Anand



Re: why it point out"unknow device"

mrjun posted on 04 Jan 2012 12:34 AM PST
Senior Member
17 Forum Posts

happy new year to everyone glad to help,

I just add the configuration of  the EP2 which had not used.

but now I don't think I have solved the problem because it happened again. Acctually, it very strange, it works on previous board but it does not work on the new board( there's not any difference between two board except their birhday), what's more, when I changed the code

(code 1)

if(!(EP2468STAT & bmEP4EMPTY))
  {
    {
   //count = ((EP4BCH << 8) + EP4BCL) & 0x03FF;
    count = (EP4BCH << 8) + EP4BCL;
     cmd=EP4FIFOBUF[0];
       
  // loop EP4OUT buffer data to EP8IN
        for( i = 0x0000; i < count; i++ )
        {
           // setup to transfer EP4OUT buffer to EP8IN buffer using AUTOPOINTER(s)
   RAMBUF(0x200+i)=EP4FIFOBUF[i];
        }
  RAMBUF(0x3FE) =1;
        SYNCDELAY; 
        SYNCDELAY;                   
     OUTPKTEND=0X84;
     }  

to

 

(code 2)

if(!(EP2468STAT & bmEP4EMPTY))
  {
    {
   count = ((EP4BCH << 8) + EP4BCL) & 0x03FF;
   // count = (EP4BCH << 8) + EP4BCL;
     cmd=EP4FIFOBUF[0];
       
  // loop EP4OUT buffer data to EP8IN
        for( i = 0x0000; i < count; i++ )
        {
           // setup to transfer EP4OUT buffer to EP8IN buffer using AUTOPOINTER(s)
   RAMBUF(0x200+i)=EP4FIFOBUF[i];
        }
  RAMBUF(0x3FE) =1;
        SYNCDELAY; 
        SYNCDELAY;                   
     OUTPKTEND=0X84;
     }  

or to

(code 3)

 if((!(EP2468STAT & bmEP4EMPTY))&&(count>0)  )
  //if(!(EP2468STAT & bmEP4EMPTY))
  {
    {
   //count = ((EP4BCH << 8) + EP4BCL) & 0x03FF;
    count = (EP4BCH << 8) + EP4BCL;
     cmd=EP4FIFOBUF[0];
       
  // loop EP4OUT buffer data to EP8IN
        for( i = 0x0000; i < count; i++ )
        {
           // setup to transfer EP4OUT buffer to EP8IN buffer using AUTOPOINTER(s)
   RAMBUF(0x200+i)=EP4FIFOBUF[i];
        }
  RAMBUF(0x3FE) =1;
        SYNCDELAY; 
        SYNCDELAY;                   
     OUTPKTEND=0X84;
     }

It works. I can't find any expaination on EZ-USB® Technical Reference Manual, wish helps,thanks.

(remarks: the difference between code 1 and 2 is the green part;  code 1 and 3 is the yellow part)



Re: why it point out"unknow device"

aasi posted on 04 Jan 2012 09:29 AM PST
Cypress Employee
1090 Forum Posts

mrjun,

Not able to get the full picture from your description. Please create a tech support case (MyAccount -> MyCases) so that one of our engineers can look into this.

Regards,

Anand






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