XBee S2 ZB RSSI info on Pin6

Hi everyone,

I’ve just started up using XB24-Z7 modules for a simple experiment for my school project.
I’m using pin 6 output for obtaining RSSI value but even though I’m getting values from the pin, the values does not really make sense for me and I’m quite puzzled.
As a comparison, I observed the RSSI value in dB using AT command and the value decreases as the distance increases as expected.
However, when I used pin 6 out the followings were the values I got: 3ft-48%, 6ft-28%, 9ft-49%, 12ft-35% and 15ft-32%. There may be a few percent differences but the results I got were quite consistent.
If I simply use the values that got to convert them to get dB, the results become very low. If i’m not mistaken, even at 3ft, the value is below -80. So not only the trend does not any similarity to the result using AT command, but also the dB converted values are way too low.
Another thing that I’m not clear about is that up to 6ft, the counts for one square wave length was 2400 but it became 1200 at and after 9ft. So actually the % calculations that I mentioned above is base on 1 wave length for the first two measurements and two wave length for the 3rd and after.

I’m just kind of lost at this point. I hope anyone can point me out to the right direction so that i can actually use pin6 output for obtaining right RSSI dB values.
I may be making very stupid mistake but I don’t have any clue.

Thank you for your time and help in advance.


RSSI provides approximate result for received signal strength. The signal quality matters on many parameters as fresnel zone, distance between two nodes, external RF interference, WIFI channel conflict etc…

So, the best measure for placement of the nodes, is the loop back test. If more than 90 % of the sent data are received back then the signal quality is good.

Hi shahrj1988, thank you for your reply.

I understand that RSSI is not so reliable when trying to estimate distance between nodes, but I need to use it for my school project.
I could use RSSI dB value that I can get by using X-CTU with AT command for instance, but the efficiency to obtain enough data is not good and I need to create a small device with other sensors with XBee. So if I can use RSSI from Pin 6, it would facilitate my work on the project.
I’d appreciate if you can tell me that the value from Pin 6 is supposed to provide the similar RSSI values as AT command gives.
I’m not sure that how or even if it is possible to get RSSI values in dB similar to what we can get using AT command at the end?

Anyone’s input is very much appreciated.

I hope, you are referring to pwm output for rssi. Yeah, its the same and works on the same principle.

And you ca display the rssi in the visible form using 3 leds. It seems, it is time to refer XBIB-R-Dev board schematic. By the way it there on digi website… Googling can help you to find that.

All the best…