EM-406a Connections

Forum 2005-2010 (read only) Hardware Interfacing
1

Hello

I am going to be hooking up the EM-406a to my Arduino board via newSoftSerial and had a question regarding the TTL levels.

Can I connect the EM-406a directly to the arduino's I/O lines?

I believe the Arduino uses 5V TTL and the GPS uses 3.3V TTL, correct?

Thanks for your help!

2

I don't speak from experience but there could be a problem. The EM-406a datasheet says its output voltage is in the range 0V-2.85V, which might not be a high enough voltage to be recognized as a logic high (but then again, it might...most of the time). Enabling the input pin's pull-up resistor should solve the problem if it exists.

On the transmit side, use a voltage divider (two 10k resistors for example) to bring down 5V to 2.5V.

3

Here's how Adafruit handles the 406A on their GPS Shield.

1473×1098 24.9 KB

4

Fine link, helped me alot.
Thank you again
Regards