Microcontroller - Monitoring Application

[reubenn]

I've designed a monitoring transmitter-receiver system in which the o/p of the receiver is :
1> A rectangular wave of peak-to-peak voltage 4.6V, on-time 600usec, off-time 800usec when the transmitter signal is being received.
2> A DC voltage of 1.7V when the transmitter signal is absent.
How do i use this condition so that the uC knows when the transmitter signal is absent ?

 

[bobsanjose]

1> A rectangular wave of peak-to-peak voltage 4.6V, on-time 600usec, off-time 800usec when the transmitter signal is being received.

You could use a timer and check for high and low levels every 200 usec. If you 5 times or more the same level, there is no transmitter signal.

2> A DC voltage of 1.7V when the transmitter signal is absent.

If your micro has an ADC or a comparator, this is your best option to convert the voltage two times to make sure it wasn't just a transition that you sampled. If two times the value is within a narrow margin of 1.7V, you can be sure it is inactive.

Bob
**broken link removed**

 

[saeed_pk]

if You USE PIC
then Use External Interrupt or CCP(Capture) Module for Signal Presence and you can have same timeout routine for absence of Transmitter