Esp32 upload port

Hi guys

I’m New to platformIO and try to use platformIO IDE to develop firmware for Esp32, install the IDE on the mac and ini. the IDE seems OK, try to load the example program to the board, it stop to upload the firmware to the board because the IDE can’t find the “upload port” from the ini file. the following are the error massage from the terminal window;

[Fri Jan 6 19:52:21 2017] Processing esp32dev (platform: espressif32, upload_speed: 115200, board: esp32dev, framework: arduino)

Verbose mode can be enabled via -v, --verbose option
Collected 3 compatible libraries
Looking for dependencies…
Project does not have dependencies
Looking for upload port…

Error: Please specify upload_port for environment or use global --upload-port option.
For some development platforms it can be a USB flash drive (i.e. /media//)
*** [upload] Explicit exit, status 1
========================== [ERROR] Took 1.67 seconds ==========================

Anyone can help?
great appreciated!

Edward

been solved, need to install cp2102 usb-to-UART driver for mac!