It would be very helpful if you could answer early.
Please check Hardware design guide (page #03-04) for PSOC 5LP available at this link describing about power connections as required:
Thank you very much for your reply.
We have already considered the operating conditions in "AN61290 PSoC® 3 and PSoC 5LP Hardware Design Considerations.pdf".
We know that this PSoC5LP power supply separation is perfect and has an available regulators in it.
We would like to know how to switch between "USB regulator enabled" and "USB regulator bypassed".
Is our understanding like below correct?
[In case of VUSB_5]
1. Setting VDDD of "Operating Conditions" in PSoC Creator "System Tabs" to 5V and supplying +5V for VDDD.
2. If we build the project, the USB power supply is automatically fixed in "VUSB_5" with "USB regulator enabled".
[In case of VUSB_3.3]
1. Setting VDDD of "Operating Conditions" in PSoC Creator "System Tabs" to 3.3V and supplying +3.3V for VDDD.
2. If we build the project, the USB power supply is automatically fixed in "VUSB_3.3" with "USB regulator bypassed".
[In case of VUSB_3]
1. Setting VDDD of "Operating Conditions" in PSoC Creator "System Tabs" to 3V and supplying +3V for VDDD.
2. If we build the project, the USB power supply is automatically fixed in "VUSB_3" with "USB regulator bypassed".
Yocchi & Hayato
The USB block can operate in two voltage ranges :
■ Standard voltage range – 4.35 V to 5.25 V
■ Low voltage range – 3.15 V to 3.45 V
USB needs a nominal voltage of 3.3 V for its operation. It supports an internal regulator which is used for voltage regulation. While in the Standard Voltage Range, the voltage is regulated to 3.3 V by the internal regulator. While in the Low Voltage Range, the internal regulator should be bypassed.
The “reg_enable” bit in the USB_USB_CR1 register is used to control the regulator.
I think by reading this "reg_enable” bit value in code, you can confirm your understanding about USB regulator's mode on setting the power supply values in PSOC Creator.
Details about this bit will be given in Register TRM of PSOC5LP available on internet at this link:
Hello Yocchi and Hayato,
If you want to use the USB regulator enabled mode, then while calling the USBFS_Start(uint8 device, uint mode) function set the mode parameter as USBFS_5V_OPERATION, this will enable the voltage regulator automatically by setting the “reg_enable” bit in the USB_USB_CR1 register.
Set the mode parameter as USBFS_3V_OPERATION to disable the voltage regulator.
Set the mode parameter as USBFS_DWR_POWER_OPERATION to enable or disable the voltage regulator depending on the power supply.
For more details refer to the USBFS.c file generated when building the project.
Thank you very much.
I agree with you but I have two questions.
1. Device Number
The PSoC5LP has one USB ports. So, is the device number only '0'?
In case of "USBFS_DWR_POWER_OPERATION" parameter, it is determined by the voltage applied to VDDD to
enable or disable the voltage regulator.
It is not necessary to configure the operating conditions of "System" tab in PSoC Creator.
Why can we configure the voltage in "Operating Conditions"?
Yocchi & Hayato
Regarding 1) For the USBFS Component, you can create more than one device descriptor out of which only one will be active at a time.
Each device descriptor created will have a different device number. To add a device descriptor, click on 'Descriptor Root' in the tree view and click on add another device. The device number is used to identify which descriptor is sent to the host when PSoC device tries to enumerate.
For 2) Setting the 'Operating Conditions' is necessary when using USBFS_DWR_POWER_OPERATION because depending upon the value of VDDD set in the Design Wide Resources the voltage regulator will be enabled or disabled. The function will pick the VDDD value from the Operating Condition set.
Thank you for your reply.
We understood this.
It was helpful for us.
Yocchi & Hayato