Hello @oracle_sod
ok, I see, the DFRobot version has an UART interface. M5ExtIO2 GPIOs can be set to multiple modes (input, output, ADC, servo, neopixel and PWM) but I am afraid none of these modes can be used for an UART connection.
According to the wiki page RX is used to select the mode, this could be achieved via M5ExtIO GPIO set as output.
However the TX line sends data with 9600 Baud, which I doubt M5ExtIO2 can handle.
That said, what is the reason you don't connect all three Ultrasound units directly to the M5Core? That would require 6 GPIOs.
And if you could live with the fact that all three Ultrasound units use the same mode you could get away with only 4 GPIOs, 1 GPIO to select the mode for all three units, and 1 GPIO for each unit to receive the UART data.
Thanks
Felix
