8 Replies Latest reply on Nov 8, 2019 5:33 AM by LePo_1062026

    Maximm UART channels on "CY8C5467LTI-LP003" ?


      "CY8C5467LTI-LP003" in the datasheet i can not find the max number of UART channels, which specific pins i can use as UART on this chip? and how much the maximum baudrate i can get? is it related to crystal?

        • 1. Re: Maximm UART channels on "CY8C5467LTI-LP003" ?



          I could generate application with 7 UARTs.


          But failed with 8 UARTs.


          So I suppose 7 is the maximum number.






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          • 2. Re: Maximm UART channels on "CY8C5467LTI-LP003" ?



            1: Open the uart datasheet, we could find the resources component occupy, like the below screenshot:

            2: Open the corresponding chip project in creator: then programming the project, open the result--> .rpt file. You could find the resource type:

            3:  So if you use the full uart (RX+TX), the max number is seven. But if you use RX only or Tx only it will more than 7 seven.

            4:  Yes the baud-rate it related to crystal. uart clock = baud-rate*oversample*data bits

            5: More information about the UDB uart, you could refer to the component datasheet.

            6: Hope it is helpful for you.

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            • 3. Re: Maximm UART channels on "CY8C5467LTI-LP003" ?

              Thanks for this information, is there any dedicated UART pins for this chip or i can use any as per PSoC creator suggested pins for UART?

              • 4. Re: Maximm UART channels on "CY8C5467LTI-LP003" ?

                PSoC5LP: The UDB UART has no dedicated UART pins. You can use any pin which PSoC Creator suggested.

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                • 5. Re: Maximm UART channels on "CY8C5467LTI-LP003" ?



                  How many UARTs do you need?


                  It appears from the experiments performed by our friends responding to your post, that 7 UDB UARTs is the limit.  This limitation is because of the UDB resources available.


                  There are three additional options open to you to potential increase the UART port functions.


                  Option 1:

                  If one or more of your UARTs are used for Transmit-only functions, there is a Software Transmit UART component that doesn't directly use any UDB cells.  It requires some FLASH and RAM and may be a little performance limited.  But since UARTs by it nature can be Asynchronous (hence the 'A' in UART), slight delays between transmitted byte can usually be tolerated.


                  Option 2:

                  Using the USBUART component in USBFS mode, you can perform UART functions on a host with an on-board USB circuit on the PSoC 5LP.


                  Option 3:

                  If you can guarantee that all UART ports are not in operation at the same time. you should be able to multiplex the Rx inputs and Tx outputs using a common UART or UARTs.



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                  • 6. Re: Maximm UART channels on "CY8C5467LTI-LP003" ?

                    Hello LePo,


                    thanks for the information, i will use 3 UART maximum in my application at the same time. in full duplex mode. i was just confused about the baudrate, as i can not find any specific hardware reference design for this chip "CY8C5467LTI-LP003" , with internal clock how much max baudrate i will gate? do i really need an external crystal?

                    • 7. Re: Maximm UART channels on "CY8C5467LTI-LP003" ?

                      Internal and external clock for the UART component does not refer to a crystal. The choice refers to an automatic tuned clock for your desired baud rate or a provided clock component that is configured by you.



                      • 8. Re: Maximm UART channels on "CY8C5467LTI-LP003" ?



                        Most people use the internal clock for UARTs.  It's cheaper (of course).  The standard rule-of-thumb is that the baud rate tolerance at either end should be no more than +/-4%.  If one end varies more than that, you might start getting framing errors.


                        If you do go with the internal clock, select one of following IMO frequencies in the Clock tab of the DWR:

                        • 3MHz +/-1%.
                        • 6 MHz +/-2%
                        • 24MHz with the USB Clock Enabled and the ILO set to 100KHz.  This has the tightest tolerance of +/- 0.25%

                        Using a Crystal for the ECO is more accurate but is overkill if not needed for other reasons.


                        About maximum baudrate:

                        Here's a clip from the UART datasheet.  Depending on your use, you can achieve different frequencies.

                        The chart above is in UART clocking frequencies.  To obtain baudrate possible take the max frequency that applies for you and divide by 8 (oversampling).


                        Doe this help?