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USB Hosts Hubs Transceivers

BradCarlson
New Contributor

I have a developed product.  Things have been working great over 1000 hubs made.  We started a new reel of  chips some work and others do not.  The ones that work are identified by the HOST and all 4 down stream ports work.  The chips that do not work, nothing happens on the host side.  Normally with USB we get a not recognized device.  Is the ROM different with some chips.  We have an EEPROM but not using it.  The ones that work do not need the EEPROM, my understanding is it is using the ROM defaults.  Could we have bought incorrect parts.  The chips show CY7C65632-28LTXC on the package.  Can the ROM defaults be different with the same part number.

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1 Solution
MallikaK_22
Moderator
Moderator

Hi,

The default configuration for the hub is mentioned on Page 16 in the HX2VL datasheet . Under each field which is configurable by EEPROM, the default value is mentioned towards the end.

Please see the USB traces requirement from the App Note and check if you comply with them.

Do you have our HX2VL kit? Probably you can try to replace the chip on out board with the bad chip and check the behaviour.

Regards,

Mallika

Mallika

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8 Replies
MallikaK_22
Moderator
Moderator

Hi,

Please provide additional details such as the schematics, is the board self powered or bus powered.

Also, I could not understand if the hub is enumerating on the host or not? Please share the screenshot from Device Manager

Additionally, kindly provide USB traces from a hardware analyzer such as Lecroy when the hub is connected to host for the FAIL case.

Regards,

Mallika

Mallika
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BradCarlson
New Contributor

Thank you for your quick response.  NOTHING HAPPENS.  It does not enumerate, it does not say unrecognized device.  I have attached the screen shots and the schematic.  It is self powered.  I do not have Lecroy.  We have built over 1000 hubs to date no problems.  The last reel of cypress chips about 50% failed and 50% worked fine.  Same lot of PWBs and associated parts.  We have changed the Cypress chip between a good board and a bad board.  The failure followed the chip.  The good board quite being recognized (NOTHING) with the bad cypress and the bad board worked fine with the good cypress chip it was recognized and enumerated and all 4 down ports worked.  Therefore I do not feel we need to look at anything but the chip.  The question I had is all the chips programmed with the same ROM.  In the data sheet it talks about ROM differences.  If there are different factory ROMs how do I know which ROM I am purchasing.  Any suggestions will be appreciated. 

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MallikaK_22
Moderator
Moderator

Hi,

The default configuration for the hub is mentioned on Page 16 in the HX2VL datasheet . Under each field which is configurable by EEPROM, the default value is mentioned towards the end.

Please see the USB traces requirement from the App Note and check if you comply with them.

Do you have our HX2VL kit? Probably you can try to replace the chip on out board with the bad chip and check the behaviour.

Regards,

Mallika

Mallika

View solution in original post

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BradCarlson
New Contributor

Thank you.

1.  Can the default be different, has there been CY7C65632 with different defaults built by Cypress and the supply chain has got things confused and sent us the wrong ROM.  We are only using the defaults and not the EEPROM.

2. Yes we comply with the USB traces.  We have built over 1000 boards until we ran into this bad reel of parts.  Every thing worked great so the traces are good.

3. We have proven a good chip works on a board that failed and the bad chip causes a good board to fail.  We have two other products that use this same chip.  We have built several 1000 of those products with no issues.  I do not see where the HX2VL kit helping any more than that.  Can you explain how.  If the kit had a zero insertion connector for the chip then I could screen all the chips but it does not.  The chip has to be soldered on.  Therefore we are now making a zero insertion connector board for this purpose.  Do you know of any test boards that have this type of connector so we could screen all the chips?

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MallikaK_22
Moderator
Moderator

Hi,

Yes, the defaults are same for all the chips. Even without the EEPROM, the chip should have got recognized.

The DVK corresponding to CY7C65632 28-QFN is CY4608. You can solder the chip for verifying it. 

Regards,

Mallika

 

 

Mallika
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BradCarlson
New Contributor

Why would you suggest the CY4608.  I have 1000s of boards that work great using this chip.  One of those working boards would tell me the same thing as the CY4608.  We have unsoldered and exchanged chips on a good working board and a bad board.  The error went with the chip.  Can you explain how the CY4608 will tell me anything different than that?

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MallikaK_22
Moderator
Moderator

Hi,

I'll discuss this with you over a private message.

Regards,

Mallika

Mallika
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