PSoC 5 in Creator 2.0 needs XTAL clock for USB - Cypress.com Forums http://www.cypress.com/? Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=63854 Wed, 06 Jun 2012 02:35:29 -0600 Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=61381 To answer my own question about the capacitors: it depends :) One needs to look up the data sheet for the crystal to be used, and then calculate the capacitors from that. When using the formula Cload=((C1*C2)/(C1+C2))/Cstray, and assume that Cstray is 10pF (5pF for the PCB, and 5pF for the PSoC5 inputs, according to the data sheet), the 12pF and 22pF values are not that far off.

I soldered my crystals on the -050 yesterday. The one I used was specified with a load capacitance of 20pF, and I soldered 22pF capacitors (the formula above gives 20pF). Soldering the 0603 parts was a real pain, and I needed multiple tries to get it right :(

My testcase was to divide the crystal frequency by 256, and using this clock to drive a 16bit PWM block. This gives a nice 1.4 second period, and worked right from the start.

After that, I tried the USBFS-HID example project, which naturally didn't work... The reason in the end was that the code specifies a 3.3 volt supply, but the project was somehow set to 5 volts (and the board too). After changing the code to set a 5 volt supply, everything worked fine.

Since I was using a 12MHz crystal instead of the recommended 24MHz one, I did use pavlovens trick from above: use the crystal as source for the PLL, and create the needed 48MHz frequency from that. Then one can use the PLL to drive the USB clock. Hte only disadvantage of this is that the PLL then cannot be used to create another frequency, which might be needed in some cases.

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Tue, 03 Apr 2012 06:41:24 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=59808 Pavleon Great job !

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Tue, 28 Feb 2012 00:45:25 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=59782 I think that a  little sum-up would help here...

The root of the problem is that the IMO is not accurate on PSoC 5 as we would like. As a result USB, when clocked from the IMO, would fail certification. It might "work" but would not be compliant. We added a design check for that siutation in the 2.0 release.

The easy fix is to add a crystal to the design and set up XTAL as the USB clock. The design check directs you to do just that. But, we forgot another viable solution; using an external clock signal. It should be possible to put a good clock onto a GPIO and use that as the USB clock. The design is attached, showing how to name the signal and use it in the Clock editor. Sadly, the design check we put in erroneously prohibits using XTAL as the IMO source and using that for USB. We'll fix that in the next release.

But, there's more. In the last post pavloven has cunningly shown a way around the bogus error. Instead of using IMO as the USB clock source, he runs the IMO through the PLL and then to USB. This dodges the error condition and lets you run USB without a crystal (you still cannot run it off the internal IMO clock though). Nice job, pavloven, we'd not thought of that one! Of course, this does put a bit of a restriction on what you run the PLL at but that may not be a problem in your designs.

-- Mark.

 

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Mon, 27 Feb 2012 12:01:14 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=58661 I solved this problem for CY8CKIT - 014 by applying a digital signal from the generator to P5.7
I hope that this solution is acceptable.

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Fri, 27 Jan 2012 16:25:29 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=58471 Charlie,

The load capacitance recommendation is just that, a recommendation. Errors in load capacitance will have a small impact on oscillating frequency.

Thanks,

Max

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Fri, 20 Jan 2012 11:34:29 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=58449 For the CY8CKIT-010, and following AN54439 equation 2:

CL1 = CL2 = 2 * CL - (CP - CB)

Let CL = 20pF (from ECS crystal specification)

Let CP = 5pF (from PSoC® 5: CY8C55 Family Datasheet page 61)

Let CB ~= 1pF (from microstrip estimate)

...how can one arrive at the 22pF value for the pi-network capacitors? 

Why was a different crystal chosen for the CY8CKIT-010?

Resolving the conflict between the table and the illustration posted in the forum post for the CY8CKIT-010 by assuming 12pF is the correct value for C26 and C27, and matches the ECS specification of a 12pF for CL,  again, how can one arrive at the 12pF value for the pi-network capacitors using equation2?

How can this information be applied to the design of a Cypress customer's PCB for the PSoC5?

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Thu, 19 Jan 2012 19:06:06 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=58292 Even if you downgrade the version of the USBFS component, as long as you use PSoC Creator 2.0, you will have to use an external crystal for PSoC5.

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Mon, 16 Jan 2012 00:47:04 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=57832 Has anybody tried to down-grade to an older version of an USB-component? Is that possible?? Will it work (without x-tal)???

Bob

 

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Tue, 03 Jan 2012 04:36:17 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=57819  I'am still asking why not let the option to choose IMO as USB clock source as this is possible in Creator 1.0?

Franz

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Tue, 03 Jan 2012 00:40:42 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=57817  The need for using an external crystal was documented during Creator 2.0 release in this Knowledge base article on Cypress website.

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Tue, 03 Jan 2012 00:01:51 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=57816

This link http://www.cypress.com/?rID=55948 has documentation on migrating designs between different silicon, software versions. It can be accessed from Creator from, Help -> Documentation -> Migration Guide.

 

Regards,

-Vivek

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Mon, 02 Jan 2012 23:39:24 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=57813 It was a cold shower after installing 2.0 and an external XTAL is required to compile my old project. I'm really sorry to read this. We are just starting production with a NO-XTAL-design that we have iterated several revisions during long time. We haven't found any problems or seen any warnings about the USB-communication. And nothing is mentioned about that in new features for Creator2.0 nor on the Cypress site either, only now in this thread. Really bad. I'll say Cypress is lucky to have saved my 1.0-files as backup before installaition of 2.0. We will have to stick to Creator 1.0 until next revision of our PCB. Not happy :(

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Mon, 02 Jan 2012 17:13:27 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=56977 Any crystal in the range 4 – 25 MHz can be used. The crystal input can be locked to any frequency in the range 24 – 67 MHz using the PLL; same can be used as Master Clock for the system. The tolerance on the PLL is dependent on the tolerance of the input clock; that is the crystal. Chosse a crystal which is accurate enough for your frequency.

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Mon, 12 Dec 2011 02:42:44 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=56967  As long as the PLL is using a XTAL as the source, it should be OK.

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Sun, 11 Dec 2011 23:03:22 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=56964 Can I use a 12MHz crystal as well? (I just have one laying around, but not a 24MHz one). I would neet to change the configuration, but I don't know whether USB / UART uses the IMO directly or the master clock...

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Sun, 11 Dec 2011 13:45:30 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=56901  Why not leave using IMO for USB as an option? Maybe showing warnings or notices? As said I did not had any failures with Creator 1.0.

 

I think wih external crystal you will lose flexibility for some applications.

 

Bye

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Fri, 09 Dec 2011 02:51:34 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=56869 Is it really a 12pF capacitor for the -010? The image shows 22pF capacitors, and the datasheet says the same (and AN54439 too)..

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Thu, 08 Dec 2011 02:11:53 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=56865  Oops, something went wrong I guess. Attaching a pdf that has the same content.

 

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Thu, 08 Dec 2011 00:55:34 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=56864  In order to use the external MHz crystal in your PSoC Creator project, the following setting needs to be done in the Design Wide resource file of the project: 

 

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Thu, 08 Dec 2011 00:52:01 -0600
Re: PSoC 5 in Creator 2.0 needs XTAL clock for USB http://www.cypress.com/?rID=56862 Listed below are the recommended crystal and the capacitors for PSoC5.

CY8CKIT-050:

Y3

CRYSTAL 24.000MHZ 20PF SMD

ECS Inc

ECS-240-20-5PX-TR

C30,C31

CAP, CER, 22 pF, 50V, 5%, COG, 0603, SMD

Panasonic - ECG

ECJ-0EC1H220J

 

CY8CKIT-010:

 

Y2

CRYSTAL, 24 MHz, 30 ppm, HC49, SMD

ECS Inc

ECS-240-12-5PX-TR

C26,C27

CAP, CER, 12 pF, 50V, 5%, COG, 0603, SMD

Murata Electronics North America

GRM1885C1H120JA01D

 In case of CY8CKIT-010 ( PSoC CY8C55 Processor Module) the crystal and the corresponding capacitors(C26 and C27) should be mounted as shown in the picture below:

 

 

In case of CY8CKIT-050, the crystal and the corresponding capacitors(C30 and C31) should be mounted as shown in the picture below: