Hi,

When using UART & USB, i must use IMO at 24Mhz to get USB clock 48Mhz, however this give me tolerance 4% and it's not accepted by UART which need at least 2% tolerance.

Do i need to use XTAL in this case?

Thanks

Arenosoft,

Were you able to see error in UART communication practially  while using IMO of 24MHz?

Hi,

Doing simple testing, there wasn't any error in 1 UART tx/rx.

It's a warning in Clock design that I was curios about, I intent to use 7 UARTs and 1 USB.

Can I ignore that warning?

Thanks

Hi,

Using IMO with 4% tolerance might not be of concern if  you are transmitting in bursts, that is, you send data with intervals.

However, if you are transmitting very long chunks of data in a given time, then the small time error might accumulate over a period of time and may result in a bit error which might manifest itself in the later part of the transmission.

Using 2 stop-bits might come in handy to get over this issue.

You can use many UART components as these are UDB based components.

 Thank you for your information, I will give it a try

Regards

Hi,

In case of USB clock using IMO, the clock syncs with the accurate clock of the USB host (like PC) and hence the clock tolerance reduces to 0.25%.