13 Replies Latest reply on Jul 6, 2016 1:27 AM by userc_39618

    8-bit UART with PSoC 5lp




      I want to transmit some text through UART using PSoC 5lp (CY8C5868AXI-LP035) board. But I couldn't understand while transmit or receive which pin should i select for tx or rx. Because in the pin specification they didnt mention the tx and rx pin specifically. In PSoc 5lp board P5 connector contains rx, tx, cts, rts but it is not connected with the RS232 connector and i checked this by continuity. Gve some useful reference and help me bro......

        • 1. Re: 8-bit UART with PSoC 5lp
                  You can't connect a RS232 signal directly to the Psoc 5lp. The RS232 signal is connected through kit prog on the USB connector. If you want to interface to RS232 signals you would need to add a MAX232 device or similar to the pins on the board.   
          • 2. Re: 8-bit UART with PSoC 5lp

            Here is a picture of where the UART output pins are.


            If you want to use the UART signals then all you need to do is connect the PSOC 5lp to your computer using the USB  and get a terminal program such a Putty or some other terminal program.  If you want to connect it directly to a RS232 cable you need this circuit. Just connect the Uart RX and Uart TX pins to the MAX232 Pins 11 and 12 and your RS232 to the pins 14 and 13 that is alll you need to do, .



            • 3. Re: 8-bit UART with PSoC 5lp



              BOB i am using PSoC 5lp (CY8C5868AXI-LP035) board. So i can find rs232 and max 232 device. I have attached Photo of the device here. I thing your answer is correct for PSoC 4 pioneer kit. But still i am not clear about this.  Thanking you.....bob for the reply

              • 4. Re: 8-bit UART with PSoC 5lp

                I gave you the schematic for the PSOC 5LP board not the large board that  Cypress makes.  One other thing you need to design a UART component into your board design before you can get any UART signals.   I think this is the kit you are talking about.



                1 of 1 people found this helpful
                • 5. Re: 8-bit UART with PSoC 5lp

                  Here is an example program. You may need to change the  pins  used to match your kit.

                  • 6. Re: 8-bit UART with PSoC 5lp

                    I assume you are referring to the CY8KIT-050 LP5 board. Your TX and RX connections are marked on the female header next to the breadboard in front of SW2. I avoided building my own circuit and used a FTDI TTL-232R-3V3 USB to TTL Serial Cable available from Adafruit and other vendors. You need to connect the header TX to P0-1 both by hardwire and in your .cydwr pin config. Connect your RX cable to the board's TX. If you also use full duplex connect the cable's TX to the board's RX.

                    • 7. Re: 8-bit UART with PSoC 5lp

                      Bob, I had built the same program which you attached above. I found this from examples before u sent. After built this i got the result of 20-7f ASCII value on LCD display but the same data was not transferred to hyper terminal. Again I tried by changed this from external clock to internal clock with 9600bps but  got same result.  My doubt is if i used the UART component, I have to select the pin of tx or rx. For example, P6[5] is used for onboard POT. Same like i need for on board UART pin specification. I couldn't find this from hardware details of the board.  Otherwise tell me how to connect the tx or rx pin to on borad UART.  

                      • 8. Re: 8-bit UART with PSoC 5lp

                        When you install the DVK only files from here you will get the schematics installed under Program Files(x86)\Cypress\...


                        Have a look at P5 to connect the PSoC 5 UART signals to the MAX232





                        • 9. Re: 8-bit UART with PSoC 5lp

                          Sheik, Did you see my comment above? Connect a jumper wire from TX on the board's female header to pin P0-1 as instructed on the top design page Bob sent. Connect your cable RX to the board's TX. When you do your clean and build check the cydwr diagram to see that the pin P0-1 (pin 72) got connected to TX.

                          • 10. Re: 8-bit UART with PSoC 5lp
                                    Does J37 have a jumper or is it open? That is the power jumper for the RS232 chip.   
                            • 11. Re: 8-bit UART with PSoC 5lp
                                      I think I have the answer to this . The RS232 chip is not connected to 5lp chip it is connected to the RS232 connector and 4x1 RECP P5 only you must provide the jumpers to the the 5lp chip.   
                              • 12. Re: 8-bit UART with PSoC 5lp

                                Thank you very much ... I traced out my problem. Ur answer is correct. I done some small mistake.

                                • 13. Re: 8-bit UART with PSoC 5lp

                                  Hi bob,


                                  Thanks to all, those who are helped me and special thanks to bob. bob actually i done two mistake. first one is i didn't check the connection between DB9 female and DB9 male.  Second thing was i expected pin specification like 8051 which means P3.0 and P3.1 used for rx and tx. Sorry to all and i learnt from u a lot...again i would like thanks to all forum members.


                                  Now its working............