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Does the PMC-Eight automatically switch back to the WiFi channel when it reboots or when powering it up?


No, it does not. There is nothing in the firmware which forces it to select back to WiFi when the PMC-Eight powers up.

Unless the ESX! command is sent to the controller, it will stay at its current value. Having said that, you will find that the SSID for the PMC-Eight is still available for connection on your device and you can in fact connect to it as the WiFi module always powers up when booting up the PMC-Eight. The firmware switch value selecting the communications port (channel) is stored in the EEPROM (permanent) memory and can only be changed by issuing the ESX! Command to the controller.

If you have switched to the serial channel and you cannot make the serial connection work after switching the channel from WiFi to serial, then there is something else going on with your connection. You may have an issue with your serial adapter cable. To verify that your serial adapter cable works fine, you can do the following procedure:

  1. Connect your serial cable to your compute
  1. Determine the com port assigned to your cable.
  1. Start the Parallax Serial Terminal Program

Download Parallax Serial Terminal Program

  1. Select the proper com port and set the BAUD rate to 115200
  1. Power up the PMC-Eight Controller
  1. The splash screen for the PMC-Eight should show up in the terminal verifying that you have proper communications with the controller.
  1. OPTIONAL - You can send a command via the terminal to see the controller respond, %%% (Diagnostics Mode OFF), or ESB! (reboot).

If you do not see the splash screen when you issued the ESB! Reboot command, then verify that the controller is selected to the WiFi channel by connecting to the PMC-Eight SSID and making sure it works. If that works fine, then do the following:

  1. Go through the procedure again to switch from WiFi to Serial.

PMC-Eight Application Note AN002 - Switching Communications Channel

  1. Try and connect to ExploreStars again to make sure you have switched to the serial connection.
  1. Follow the procedure above to see if you get the splash screen. If you do not see the splash screen, then you most likely have a failure in your serial adapter cable.

Ensure that you have an adapter cable that uses the FTDI chipset and that it is working properly. You can purchase an FTDI serial adapter cable online. Here is the one that we recommend:

Parallax USB Serial adapter cable  

Remember, when switching from WiFi to serial using the ESX! command, you should see ESX0! as a response on the terminal screen verifying that it is selected to the serial channel. If you do not see a response, then it did not switch.