I'm re-doing a project that originally used an Arduino Mega. I wanted to use a Teensy 4.1 but it's short on pins and voltage level...etc. I have to make some changes basically to work around some firmware issues and I figure I may as well just switch to the Teensy since I have to redo the PCBs. The original thing was a Break out board for the Mega and a 32key matrix keypad/w LEDs. On the new design I'm using MCP23017's on the keypad. and this has to go over cable about 2ft long. When I do board to board stuff with the Teensy I generally use a TCA39309 which is an I2C level translator (3.3v to 5v).
I started to do the schematic with the level translator but then I thought about how finicky I2C is. I came across the P82B715DR bus extender that's meant specifically for cabled I2C but it's suggested to use one on both ends of the cable. I'll likely use some 4C, 2 twisted pair, 2 shielded 18awg cable as I have plenty of it on hand with JST connectors on both ends. The thing I'm not sure about is if it's necessary or it's overkill to use the bus extender ICs vs just using the level translator on the Teensy BOB.
For reference the Teensy BOB will be replacing the BOB with the Arduino Mega and the other end of it is the keypad that's mounted to the hinged door (not in photo)
I started to do the schematic with the level translator but then I thought about how finicky I2C is. I came across the P82B715DR bus extender that's meant specifically for cabled I2C but it's suggested to use one on both ends of the cable. I'll likely use some 4C, 2 twisted pair, 2 shielded 18awg cable as I have plenty of it on hand with JST connectors on both ends. The thing I'm not sure about is if it's necessary or it's overkill to use the bus extender ICs vs just using the level translator on the Teensy BOB.
For reference the Teensy BOB will be replacing the BOB with the Arduino Mega and the other end of it is the keypad that's mounted to the hinged door (not in photo)