28X pulsin RC

[toxicmouse]

i have got an 18X to receive the pulses from a RC receiver, but the same code does not work on a 28X (pulsin 0, 1, w0).

the 18X is at 4MHz, the 28X at 16MHz. using input0 in both cases. the 18X shows the correct pulse length, from 0,85mS to 2mS, and the 28X show 0.

annoyed, i connected the 28X to another picaxe, which output servo 1, 150. using the same code as before (pulsin 0, 1, w0) the 28X read 676
676/4= 169 (/4 for 16MHz), which is not great but better than 0.

i suspect there is a problem with interfacing, as the problem only starts with the RC.

any suggestions welcome. thanks.

 

[Wrenow]

An inexpensive tool that will really help you in your diagnosis is the E-Sky Digital Servo Tester EX2-0939. The model is in this vendor's ad: http://cgi.ebay.com/Esky-digital-Servo-Tester-EK2-0939-RC-Helicopter-parts_W0QQitemZ170140104244QQihZ007QQcategoryZ34056QQrdZ1QQssPageNameZWD1VQQcmdZViewItem Another vendor with some close-up pictures is here :http://cgi.ebay.com/Esky-AUX-Servo-Tester-EK2-0939-x1_W0QQitemZ290143542951QQcmdZViewItem It both reads the output pulses from the TX and gives output pulses to the servo. Under $20 on Ebay. I have two. They have saved me a ton of time. OK, logic probe would be nice, but, if you are doing RC work, one of these jewels is a huge help. FMA Direct used to make a really nice one that was about 1/6 the size, but discontinued it earlier this year.

A couple of questions. What voltage are you running the 28X on? What voltage are you running the RX on? Do you have a common ground? Have you tried a pull-up or pull-down resistor?

Cheers,

Wreno

 

[toxicmouse]

thanks wrenow. 28X at 5,4V- batteries, RX at 6V regulated, common ground. i have not tried pull up/down resistors, what values do you recommend?

 

[Wrenow]

With your setup, I am guessing a pulldown. I am not sure what to recommend, but, if I were trying, I think I would start with what I had handy in the box, say 10KR, and go down from there. But this is only a guess as a starting point. Never had this particular issue with the 08M.

Good luck,

Wreno