USB ULPI signals connection to ZYNQ

[joniengr]

Hi, I am working of PCB design having ZYNQ and USB3320C-EZK-TR. I am using ZYNQ board as host system with USB flash drive connected as device. I am not taking power from USB cable, so how do I connect VBUS, VBAT, and VDD33.

And how to connect REFCLK

 

[KlausST]

Hi,

Microchip provides the datasheet, and a lot of Application notes to support you on your design. (Also board design files)
This should be the first place to look for informations.

Please read through them. In case there still remain questions, please refer to the according document.

Klaus

 

[dpaul]

I think this question is better suited for this forum:

https://www.edaboard.com/forums/pcb-routing-schematic-layout-software-and-simulation-programs.15/

 

[joniengr]

Regarding REFCLK (26) CMOS input., the datasheet says:

"ULPI Input Clock Mode: 60MHz ULPI clock input.
ULPI Output Clock Mode: Reference frequency as defined in Table 5-10."

"ULPI Input Clock Mode: Sourced by Link, driven on the REFCLK pin. 60MHz ULPI clock is driven on the REFCLK pin as described in Section 5.4.1.1.

ULPI Output Clock Mode: The USB3320 generates the ULPI clock as described in Section 5.4.1.2. When using the ULPI Output Clock Mode, the frequency of the reference clock is configured by REFSEL[2], REFSEL[1] and REFSEL[0] as described in Section 5.10."

Does this means that we always need external clock at REFCLK (26) CMOS input pin to get UPLI clock ? and if we connect 60 MHz at REFCLK (26) CMOS input pin then this is ULPI Input Clock Mode but if we don't have 60 MHz available then we can chose the input clock from table 5-10 and selection made by REDSEL [0] to [2]. This allow us to connect a low frequency clock then 60 MHz but then it will be Output Clock Mode ? and internally it will generate the required clock.

 

[joniengr]

Regarding ID signal is Analog input.

According to datasheet:

"The USB3320 provides full support for USB OTG protocol. OTG allows the USB3320 to be dynamically configured as a host or device depending on the type of cable inserted into the receptacle. When the Micro-A plug of a cable is inserted into the Micro-AB receptacle, the USB device becomes the A-device. When a Micro-B plug is inserted, the device becomes the B-device. The OTG A-device behaves similar to a Host while the B-device behaves similar to a peripheral."

"ID pin of the USB cable. For applications not using ID this pin can be connected to VDD33. For an A-Device ID is grounded. For a B-Device ID is floated."

I am having standard type A USB connector on the ZYNQ board with only four pins, D+, D-, +5V, GND. There is no ID pin when connecting USB Flash drive to the standard type A USB connector. This means I am not using the ID pin. I just have connected to VDD33 which is connected to +3.3 V digital power supply. Is that right to do ?

Regarding VBUS (Analog I/O), VBAT (Power) and VDD33 (Power). I have connected them to +3.3.V digital power supply. Is that also right thing to do ?

 

[KlausST]

Hi,

ID pin:
The first question has to be: Do you want/need OTG?
.. or a standard Host-Device interface?

In post#1 you say:

I am using ZYNQ board as host system with USB flash drive connected as device. I am not taking power from USB cable

So how is the USB flash drive powered then?

Klaus

 

[joniengr]

Hi, I just want to have a standard Host-Device interface. To make concept clear can I say that my ULPI will be configured as Host on the board ? because the Flash drive is suppose to connect at A type connector like a device connecting to Peripheral.

Regarding how to power flash drive, I think I need to connect +5V digital power supply to the USB connector A that will power up the USB Flash drive to store data.

 

[KlausST]

Hi,

for USB1.1 / USB2.0 standard host: use a Type A connector.
ID signal is used for OTG only.

I strongly recommend to read though some good USB tutorials, Wikipedia ... best if you read the USB specification. At least the parts that apply to your project.

****

Regarding how to power flash drive, I think I need to connect +5V digital power supply to the USB connector A that will power up the USB Flash drive to store data.

There are standard circuits and circuit recommendations. Maybe with "switched power" and at least "fused" power line.

****
You are by far not the first one who wants to design a USB HOST interface. No need to re invent the wheel.

Klaus

 

[joniengr]

Hi,

I just found the answer to USB ID signal from Microchip website.

How do you connect the USBID pin in a USB hardware design? - Developer Help

microchipdeveloper.com

Because I will have only one standard USB A connector on the ZYNQ application board that means USB Host role then the pin USB ID on the ULPI has to be left un-connected.

 

[joniengr]

Hi,

The term host and peripheral application is used at several places in datasheet. I still have confusion regarding host and peripheral application, my application which is described as ZYNQ development custom board having USB 3320 UPLI and standard type A connector on the development board is a host or peripheral application ? On the standard type A connector, the USB Flash drive is suppose to be connected for data storage in my application.


I also have looked at Figures 8-1 to Figure 8-3 in the datasheet. It is not clear when we attach a USB Flash drive having standard type A connector with only four pins (Power, GND; D+, and D-) to the development board, is host or device application.

Is device and peripheral application are same ?

 

[KlausST]

Hi

HOST: is the "master" of the USB. It provides power, it controls the timing, it detect connected devices and communicates with them. They have the type A female connector. HOSTs are: PC

DEVICE: is like a "slave". It may be self powerd or from the HOST. Iidentifies itself with pulling the dataline, it answrs requests from the HOST. They may have the type A male connector (USB stick) or the type B connector (printer). Examples: USB-Stick, printer, mouse, keyboard ...

OTG: is a special mode where two devices communicate with each other .. but there is no "true Host".
Example: Printer connected to a camerea. Both are self powered. Both usually are "USB devices" .. but in OTG mode the camera can send data (pictures) to the printer.

Klaus

 

[joniengr]

Thanks for reply. It is clear that I am having Host application on the development board with female type A connector on the board, like we normally have on PC and Laptops. The board will also provide power to the USB Flash drive through VBUS switch and ZYNQ device will have software for read/write operations to the USB Flash drive connected.

Regarding USB ID pin, I have found the following references with mix info.

According to datasheet of USB3320,

Page 8: "ID pin of the USB cable. For applications not using ID this pin can be connected to VDD33. For an A-Device ID is grounded. For a B-Device ID is floated."

Page 61: Figure 8-3 "For Host applications (non-OTG), the ID pin should be connected to GND."

According to Hardware Design Checklist USB3320, available on the USB3320 main page,

Page 4: " ID (pin 5): This is the ID input, used for USB On-The-Go (OTG) applications. In OTG applications, the ID pin is used to determine the type of USB cable that is connected.

- When connected to a non-OTG device or an OTG B-Device, this pin floats and is pulled up by an internal resistor.

- When connected to an OTG-A-Device, the ID pin is pulled to the ground by the device."

I guess my USB Flash drive have only four pins, and is supposed to have type A male connector that can also be connected to PC and Laptops on female type A connector. My application is non-OTG, my application is host and my application does is not using ID pin. Where do I connect USB ID (5) of USB3320.

 

[KlausST]

Hi,

ID-pin.

I think understand now your confusion.
First please look at page 61:
It has a connector including ID_pin. (this is not the case with your application)
In your case you don`t use the ID function.
Thus you don´t need to connect the ID_pin_of_the_IC with the ID_pin_of_the_connector.

Now just remove the wire/signal that connects both.
Now you have two ID_nodes: one at the connector, the other at the IC.
--> connect the ID_of_IC with VDD33
--> the information: For Host applications (non-OTG), the ID pin should be connected to GND refers to the connector pin

*****

Page 8: "ID pin of the USB cable. For applications not using ID this pin can be connected to VDD33. For an A-Device ID is grounded. For a B-Device ID is floated."

To avoid confusion I add some informations:
NON_OTG: For applications not using ID pin (of the IC) can be connected to VDD33
OTG: For an A-Device ID is grounded internally of the IC. For a B-Device ID is floated."
(see Fig 5-1, Fig 5-10, )

*****

Hardware Design Checklist USB3320:
This is just information how ID signalling works.

*****
Summarizing.
(assumed that every device has a connector with ID pin)
* Non OTG, USB-Device: ID = floating (at the connector, since there is no OTG IC, thus the IC has no ID pin at all)
* non OTG, USB-HOST: ID = GND (at the connector, since there is no OTG IC, thus the IC has no ID pin at all)
* OTG in A-device mode (temporary HOST): connected to IC, driven LOW by IC
* OTG in B-device mode (temporary DEVICE): connected to IC, but left floating by IC

Klaus

 

[joniengr]

Hi, I have one more question regarding OTG_OC signals which is from the VBUS power switch TPS2051BDBV. I have connected this signal OTG_OC to IO HR Bank 12 (3.3 V) of ZYNQ 7030 device. I am not sure if it is ok or I need to connect this to another place.