Product User’s Manual –
6.0 HALF DUPLEX SERIAL COMMUNICATION
is using half duplex serial communication. The communication is standard
UART with 8 bit data, 1 stop bit and no parity. There is only one data pin for the half duplex
communication instead of 2 pins of normal UART communication. Thus, the main controller
as the master will need to have one control pin to switch between transmit and receive mode
as shown by the figure below. Besides TX and RX pin, main controller will need one digital
output pin as the control pin. The implementation is as shown by the logic circuit below. TX
and RX bus is merged into one single data bus.
On G15 Shield, there are options to select either pin D2 or D8 as the control pin(G15 CTRL).
Choose the pin by moving the mini jumper to the corresponding headers. If the state of
control pin is 1 (logic high), it is in receive mode (Arduino receives data from G15). Else if
control pin is 0 (logic low), it is in transmit mode (Arduino transmits data to G15).
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