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USB Low-Full-High Speed Peripherals

ChHa_1252886
New Contributor II

I have a project with the CY7C68014A that I am having difficulties getting the device to boot correctly.  When the PC sees the device it says that the Device Descriptors Failed.  When I checked the clock I noted that it was not working so I replaced it.  When I hold reset# low clock will return the device is recognized by the computer as being there but fails the Device Descriptors.  If I could get some help about what conditions need to happen prior to enumeration it would be great.  Best I can tell 3.3V comes up, Oscillator stabilizes at 24Mhz then Reset# is released.  At some point I know that the device will look for the EEPROM on the I2C Bus for firmware.

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PranavaYN
Moderator
Moderator

Hi,

CY7C68014A is functionally no different from CY7C68013A. It just consumes lesser suspend current and therefore lowering power consumption and is suitable for battery operated system.

Pulling I2C lines to 5V might be the possible reason for chip damage. Do replace the chip after changing I2C pull-up voltage.

Please refer to following Appnote on FX2LP hardware designing - https://www.cypress.com/documentation/application-notes/an15456-guide-successful-ez-usb-fx2lp-hardwa...

Best regards,
Pranava

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3 Replies
PranavaYN
Moderator
Moderator

Hi,

 

You can refer to FX2LP Boot Options Appnote for booting conditions/options: 

 https://www.cypress.com/file/43391/download#:~:text=Use%20an%20I2C%20interface%20to,loaded%20to%20on...

Please refer to similar thread where Electrical Over Stress had damaged the IC - https://community.cypress.com/t5/USB-Low-Full-High-Speed/How-to-restore-FX2LP-that-does-not-enumerat...

If you have spare IC you can try replacing it on the board and check if it enumerates properly.

 

Best regards,
Pranava
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ChHa_1252886
New Contributor II

Hello Pranava!

I hope you day has been well.  I am continuing to have this issue with the CY7C68014A not enumerating correctly.  I checked my reset and it does not go high until about 7ms after power is good.  Also the clock will begin working but stops shortly after reset.  I checked the I2C lines and do not see them toggling so I am suspicious that I may have damaged the part.  I have used almost this exact circuit multiple times with the CY7C68013A.  The differences are:

1.  CY7C68014A instead of the CY7C68013A

2.  The reset circuit is new but should by all accounts work.

3.  I usually tie the I2C lines to a +3.3V pullup instead of the +5v shown.  I have changed this and cut the +5V and tied the pullup to +3.3V but it did not allow the board to enumerate. Could this have damaged the part and be the issue?

Could you take a look at my schematic and see if there is an issue that would cause the device not to enumerate.

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PranavaYN
Moderator
Moderator

Hi,

CY7C68014A is functionally no different from CY7C68013A. It just consumes lesser suspend current and therefore lowering power consumption and is suitable for battery operated system.

Pulling I2C lines to 5V might be the possible reason for chip damage. Do replace the chip after changing I2C pull-up voltage.

Please refer to following Appnote on FX2LP hardware designing - https://www.cypress.com/documentation/application-notes/an15456-guide-successful-ez-usb-fx2lp-hardwa...

Best regards,
Pranava

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