cy8ckit-062 wifi-bt transmitting random values on UART

[Ma-_4161786]

Hello Everyone;

I am receiving continuous stream of random values on com-port when i program my kit with capsenseslider or even with blinkyLED or GPIO example without any modification in modus toolbox.

Is there anyone else who is also getting these random values on comport when anyone of these 3 program is running on this kit.

[Vison_Zhang · Accepted solution]

I think this is normal phenomenon.

On board, PSoC5LP works as an UART-USB Bridge, the hardware connection between PSOC5LP and PSOC6 as below figure.

If you don't enable any SCB component in ModusToolBox and assign P5[0]/P5[1] to it,  the drive mode of P5[1] is Analog High-Z, P5[1] pad is like break from PSOC6 silicon . As a digital input pin, the drive mode of UART_RX is digital High-Z, which has very high input resistance, very easy to coupling external noise. In this situation, the pcb trace between UART_RX and P5[1] likes a noise coupling antenna.

If you connect P5[1] to VDD or GND on board use jumper wire, then this phenomenon disappears.