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PSoC 4 MCU

New Contributor II

I am using the CY8C4247AZI-M485 on a CAN bus project. To use the internal clock to drive a CAN bus the WCO must be enabled and used to trim IMO. However when I trim IMO with WCO I cannot get a serial port UART to work. I simplified my project to just have one UART to talk to a terminal. Everything works fine as long as "Trim" on IMO is set to none. If I set the trim with WCO the UART no longer works. I have tried several baud rates and using the UART with and without "clock from terminal" selected. I make sure that the actual baud rate of the component is within less than 2.5% of the baud rate of the display terminal. In all settings just switching trim from "WCO" to "none" allows the UART to write to the terminal. This wouldn't be a problem except that the next step of the project requires the addition of a CAN bus component which will require WCO trim. Thoughts? Things to try?

Glen

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New Contributor II

Hi Ekta,

I added a WCO across pins 0.4 and 0.5 on my CY8CKIT-043 kit and the problem is solved. Thank you for your assistance.

Glen

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8 Replies
New Contributor II

I have tried both the UART (SCB mode) [v4.0] and UART [v2.50]. Neither work when the WCO trim is enabled.

Glen

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Moderator
Moderator

Hello Glen,

I tried printing a sentence on terminal using UART when the IMO is trimmed using WCO and I was able to print the sentence properly. I have attached the project below, can you please try the same and let m know if it works for you. I did not use CAN component in my project. Can you please confirm that whether the issue occurs only when when you are using CAN component ? Also can you please attach your project, this will help us recreate the issue at our side.

Best Regards

Ekta

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New Contributor II

Hi Ekta,

Thanks for looking into this quickly. I have the same problem with your project. The string is displayed is garbled. If I turn WCO trim off in the clock settings and rebuild the message displays fine.

My project also doesn't have the CAN component. I removed it while attempting to debug the problem. The main difference between our projects is that i am using pins 3.0 and 3.1 for Rx and Tx.

I am using the CY8CKIT-043 for developing the firmware while my own PCB is being built. My project file is attached. I tried attaching mu project file but it seems to big (2.5MB). Not sure why. I ran clean first.

PSoCSetup.jpg

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Esteemed Contributor II

I can't see a crystal on your picture. How and where did you connect it?

Bob

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New Contributor II

Hi Bob,

There isn't one. I though the oscillator was built into the chip. Where should it be connected and how do I tell PSoC creator where it is connected? I see that there is an ILO trim component. Is this related in any way? Thanks.

Glen

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New Contributor II

Found it. P0[4] and P0[5]. I'll give it a try. Thanks.

Glen

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Moderator
Moderator

Hello Glen

I tried programming your project on the CY8CKIT-044 which has the same PSOC device as the kit CY8CKIT-043 that you are using.

CY8CKIT-044 has WCO on the board. Your project was working fine on that board. This means the main reason behind the issue was the missing WCO on the CY8CKIT-043 kit.

Best Regards

Ekta

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New Contributor II

Hi Ekta,

I added a WCO across pins 0.4 and 0.5 on my CY8CKIT-043 kit and the problem is solved. Thank you for your assistance.

Glen

View solution in original post

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