I have an application below that requires 2 MCUs to be on a PCB, along with a single FTDI header. Both are programmed thru their RX/TX UART pins.
In normal operation, the RX pin on MCU_1 is connected to TX pin on MCU_2, and vice versa, for inter-MCU communication.
To flash MCU_1, a DP3T switch is toggled to the left to route the MCU_1 TX/RX pins to the FTDI header.
To flash MCU_2, the switch is toggled to the right to route the MCU_2 TX/RX pins to the FTDI header.
simulate this circuit – Schematic created using CircuitLab
So far, I have found DP3T switches with the following configurations:
I'm looking for such a configuration instead:
I'm guessing such a switch probably doesn't exist? How is it best then, using the least wiring/components as possible, to implement such a setup?
Best Answer
If you can guarantee that all the TX outputs will be tristated (floating) when the switch is thrown, then you can use a 4P3T slide switch wired as follows, for the given switch:
P.S. the lack of a schematic is due to CircuitLab not having appropriate symbols for a 4P3T switch.