PGA460-Q1: How far can IO signal be transmitted,I want to add a long wire,about 2.5m

user6060721,

We have not stress tested the maximum supported cable length, though up to 10m may be feasible depending on the value of the pull-up resistor on the on the IO pin, the OWU baud rate, the device’s supply voltage (car battery or lower LDO regulated voltage), and F/m (capacitance per meter) rating of the cable used. All of these variables must be considered to understand impact of the communication’s slew rate.

Depending on the F/m (capacitance per meter) rating of the cable type used, the value of the pull-up may need to be reduced as the maximum cable length is extended to maintain proper RC time constants. I have not encountered coax cabling for park assist systems, but based on my limited exposure to the cabling of these systems, I assume twisted-pair cabling is more common.

The LIN protocol typically calls for a 1kOhm pull-up resistor to support up to 19.2kBaud. The PGA460’s OWU “LIN-like” mode can operate up to 115.2kBaud, but this maximum baud rate is not recommended due to the unknowns of its resulting radiated emissions.

If using TCI at IO, the cable can be even longer due to the lower equivalent baud rate of only 3.3kBaud.

user6060721,

Yes, you can connect up to eight devices on a single UART / USART / OWU bus. The PGA460 has a three bit UART_ADDR value in EEPROM that you can change to a value between 0-7.

Note, the PGA460 device always has a factory default address of UART_ADDR=0, so you will need to program the each device's address before placing them all on the UART bus, or create an external auto-addressing circuit to isolate and update the address of each device on the bus.

See PGA460 FAQ #2.4 and #4.4.11 for additional details on the PGA460 device address and auto-addressing: http://www.ti.com/lit/an/slaa733/slaa733.pdf