Because I also intend to use /dev/ttyS2 for 1-wire communication I did some additional testing with the DS2480B.
This is my setup: - Direct connection of the DS2480B's TXD and RXD pins to ttyS2 TX and RX lines (on J6 of Fox board). - POL pin of DS2480B tied to GND - Some 1-wire devices connected to 1-wire output of DS2480B. I wanted to know whethter the 3.3V logic of the Fox board could directly interface with the 5V logic of the DS2480B (according to the data sheet the DS2480B is intended for use with 5V UARTS). Here are my results: 1. Supplying the DS2480B from an external voltage source < 4.5 V the tstfind application finds all connected 1-wire devices. 2. Supplying the DS2480B with 5.0V provided from J6, no devices are found. 3. Inserting a 1N4148 diode from 5.0 V to VDD of the DS2480B all devices are found. Conclusion: With a slightly reduced supply voltage (voltage drop across the diode) the logic threshold of the DS2480B seems to be compatible with the 3.3V logic of the board UART, interfacing of the DS2480B to the Fox board just requires an additional standard silicon diode. I would not suggest this setup for critical volume applications where reliability is of concern (supply voltage of the DS2480B slightly out of specs), but it works fine for simple workbench testing. Regards Klaus
