What I expect is that I am wiring up a network device to a twisted pair to read and write packets which will be expressed as differential voltages. The protocol is Toyota AVC-Lan which is similar to IEBus. The convention is for these terminals to be labeled TX+ for the high voltage and TX- for the low voltage.
I don't understand the code snippet below. What I'm expecting is, I'll understand which Arduino Nano pins to connect the TX+ and TX- terminals of the network.
Although I don't understand this section, I think this would be the place for the configuration I am expecting. Can anybody explain to me what is being done here?
// TX LED connected to Pin1 of PORTC
#define TX_LED_DDR DDRC
#define TX_LED_PORT PORTC
#define TX_LED_PIN PINC
#define TX_LED_OUT 2
// RX LED connected to Pin4 of PORTC
#define RX_LED_DDR DDRC
#define RX_LED_PORT PORTC
#define RX_LED_PIN PINC
#define RX_LED_OUT 4
The project is this: GitHub - douglasheld2/AVC-LAN-Module-Builder: Firmware for ATMega to Emulate ANY AVC-LAN device
It could be, that I connect the TX wires to the same ports as the resistors (as I think that's the proper termination topology) but that wouldn't explain which one is the high and which one is the low.