Hello,
i try to communicate with an R32C in UART Mode 2. I've set all the pins regarding the documentation for programming this device and used an FDTI to connect the TX/RX lines at 5V (VCC). I can see in the oscilloscope that when FDTI is trying to send a byte, the voltage-level of the TXD1 line does not get lower than 4.5V, which is not enough that MCU accept this. When i deconnect from the MCU, the level is fine and get down to GND.
I've tried to add an level-shifter to add more gain into the signal path, but get the same result.
Can you give any advice why this is happening and how to prevent it? There are no external pull-up/pull-down resistors on the board where the MCU is soldered in.