3 Replies Latest reply on Dec 3, 2019 2:22 AM by SampathS_11

    Problems using UART and external 32.768kHz crystal in CY8C29466-24PVXI

    PeCa_4386336

      I've been using the 8-bit UART in a design for some time. I've recently changed from the internal 24M clock to using external 32.768kHz cystal and the PLL to generate a 23.986MHz internal clock. Now the UART does not seem to work reliably. I'm talking to a PC and if I change the baud rate around the nominal 19200 I get either the Tx or Rx to work but not both at the same time. It's as if the Rx and Tx are using different clocks. I know the internal clock is at the right frequency by putting an 8 bit counter in a digital block and dividing down VC3 and feeding to a pin. I get exactly the expected frequency. The difference between 24M and 23.986M should just make the baud rate closer to the nominal value.

       

      Any thoughts?