Hi,

I need some clarifications rgd. LowPowerModes of FX3:

1. The CYUSB3014-datasheet describes two different suspend-modes L1 (PHY on) and L2 (PHY off):

- Am I right that both modes set the FX3 to USB3.0 LPM U3?

- How can I enter L1 or L2 using any API in the firmware? The API CyU3PSysEnterSuspendMode() doesn't allow to choose L1 or L2.

- L1 would lead to a higher current-consumption (3.52mA) than allowed by USB3.0-spec (2.5mA)?!

2. Which kind of USB-packets trigger the USB-event CY_U3P_USB_EVENT_SUSPEND?

3. According to FX3APIGuide host-requests to go to LPM U1 and U2 shall be handled by registering a callback-function using CyU3PUsbRegisterLPMRequestCallback(). The callback must return TRUE to accept the host-request and false to reject the request.

- Must the firmware set the device into U1 or U2 using CyU3PUsbSetLinkPowerState() in the callback-function or is it already implemented in the driver? If it's the latter case:

- Can I use the CyU3PUsbSetLinkPowerState() to send a device-request for switching to U1/U2 to the USB-host?

Best regards,

Rob

 USB packet will not trigger CY_U3P_USB_EVENT_SUSPEND. It is suspend condition on the bus.

The 3.52mA that you're looking at it is measured using self-power configuration. The 2mA is the only one actually drawn from USB bus. Datasheet updates with bus power configuration as well is on the way.

Yes. The firmware has to.

Regards,

Anand

Total power consumption allowed by the USB spec is 2.5mA x 5V = 12.5 mW.

FX3 power consumption for L1 is as follows
Core - 1.5mA x 1.2V = 1.8mW
VBUS/USB - 2.0mA x 5V = 10.0 mW
IO - 18uA x 1.8V typical = 32.4uW
Therefore total power consumption is 11.832 mW which is under the limit allowed by spec.

Cheers,

Anand

Hi Anand,

thanks a lot!

So do I have the choice to set FX3 either into low-power mode L1 or L2 by firmware and if yes, how to do it?

And correspond both FX3 low-power modes to the USB3.0 low-power state U3?

Regards,
Robert

Hi Anand,

besides the two open questions in my post from 02/06/12 (see above) I have two more questions:

- How can the USB-device (but NOT the host!) initiate a USB link-command to switch to LinkPowerState U1 or U2? Do I have to call just CyU3PUsbSetLinkPowerState(CyU3PUsbLPM_U1 or CyU3PUsbLPM_U2) and the USB link-command to host is then triggered by low-level driver?

 - How can the USB-device (but NOT the host!) initiate an exit from LinkPowerState U1 or U2? Do I have to call just CyU3PUsbSetLinkPowerState(CyU3PUsbLPM_U0) and the USB LFPS-signal to host is then triggered by low-level driver?

Best regards,

robert