PSOC5 IMO is not as good as it supposed to be, I think you need crystal for PSOC5 with USB. The PSOc3 should be OK without xtal I think.
Is it mandatory to have an external crystal as the clock source for PSoC5 device?
It depends on the application in which PSoC5 is used. The PSoC5 device family has a tolerance of 5% on the IMO. If your PSoC5 application has strict timing requirements it is necessary to have an accurate clock source. Especially, for projects that have communication components such as UART or USB, it is mandatory to use external MHz crystal with PSoC5
Listed below are the recommended crystal and the capacitors for PSoC5.
CRYSTAL 24.000MHZ 20PF SMD
CAP, CER, 22 pF, 50V, 5%, COG, 0603, SMD
Panasonic - ECG
CRYSTAL, 24 MHz, 30 ppm, HC49, SMD
CAP, CER, 12 pF, 50V, 5%, COG, 0603, SMD
Murata Electronics North America
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:
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:
Is it really a 12pF capacitor for the -010? The image shows 22pF capacitors, and the datasheet says the same (and AN54439 too)..
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.
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...
As long as the PLL is using a XTAL as the source, it should be OK.
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.
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 :(
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.
The need for using an external crystal was documented during Creator 2.0 release in this Knowledge base article on Cypress website.
I'am still asking why not let the option to choose IMO as USB clock source as this is possible in Creator 1.0?