What voltage for asserting high on XBee Pro 900 XSC RPSMA?

I'm trying to get binary commands working with a new xbee xsc radio. (I have transparent and command mode working and multiple radios communicating.)

The xbees are powered off the 3.3V pin of arduinos. In order to send a binary command you have to assert the CMD pin, send the command, then de-assert the pin. I'm just using a digitalWrite() on a digital pin connected to the xbee CMD pin but it isn't working. Does the xbee need the assertion done with 3.3V and not 5V? Everything else is working fine except for binary commands.

I'm not using a shield so I'm wondering if the level shifting from 5V on the arduino to 3.3V on the xbee hasn't be done for every pin. If so, I'll just use a shield.