Contents

Introduction

The 6 pin header next to the antenna connector is the serial connector, which allows communication between the ULRS and the computer or tablet.

This connector is sometimes referred to as the FTDI header, in reference to the FTDI company who is one of the main manufacturer of USB-to-serial chips and adapters.

Where to order an FTDI adapter

• Please use only genuine FTDI adapter : link to order page
• Be careful to choose the 3.3V version (follow the link above).
• The first advantage is that the electronics in hidden in the USB connector :

• The second advantage is that it works. It’s really worth the cost of using a genuine FTDI cable, as I’ve seen several clones giving many issues. For example flashing the firmware will work every three times.
• The core issue is that the atmega isn’t able to give a precise 115200 bauds serial, and gives something close but higher like 117000 bauds. This works with genuine FTDI adapters, but not with all clones.

Remarks

How to connect RX and TX

There’s sometimes a confusion, because the TX pin of the ULRS must be connected to the RX of the FTDI, and vice-versa. This is normal, for serial connection the RX pin of anything has to be connected on the TX pin of something else.

But to make it clear, you must connect the FTDI adapter pin to pin to the OrangeRX serial connector, without any crossing cable. The Wolfbox modules do have a different pinout, which is described here.

Alternative color code

Some FTDI use an alternative color code described below :

The DTR or RTS signal

Notice the important pin marked DTR on the ULRS : this is used during programming, and causes a reset that will put the module in bootloader mode.

On the alternative color FTDI cable described above, use the RTS signal in place of the DTR signal (which isn’t available).

The CTS signal

The CTS pin is not needed for ULRS.

Flashing a Wolfbox 1W module

The Wolfbox modules have a non-standard connector for FTDI.

Be careful to connect the correct pins (DTR, RX, TX, GND), taking care of crossing the RX and TX as usual.