Need help timestamping RSSI value and display

kuntalroy86: I would suggest starting a new topic thread for this.  The title of this thread really does not represent the subject discussed "eventually".

kuntalroy86 said:

I am using eZ430 RF2500 kit.  I am able to get the RSSI value in the console(of the GUI provided) of Temperature monitoring program. My problem is to display these RSSI values with respect to time. So is it possible to display the time as well along with the RSSI. In short, is time stamping possible? If yes please provide me with the desired changes in the main program or some logic to get it done. I am pretty new in this field . Please do reply...i need urgent help...Thanks a lot.

Time stamping is possible using the MSP430F2274 to keep time, read the RSSI value from the CC2500 and display those two pieces of information to the user.
However, on the eZ430-RF2500 target board, the MSP430F2274 does not have a 32.728KHz crystal connected to it, so it would be difficult to get a good, true time.  You could use the frequency of the DCO running in the MSP430 to keep track of the number of cycles from T=0 to when you perform the readings, and create a timebase within the application.  But this would not be as accurate as using a 32.768KHz crystal.

Hi, thanks a lot for your reply...

I am not concerned about the accuracy of the timings because My basic aim is to detect the missing packet from the end device.

Can you help me with the coding of receiving the time information..or can you explain any logic to get it done..

Thank You

Regards

Kuntal Ray

One thing I would like to clarify is my comments about timestamping the RSSI value, this is based on the MSP430 retrieving the RSSI value from the RF2500 and combining it with a timestamp which it is maintaining.
If you are asking how to get this reported via the GUI, then I don't have a solution for that.  I reviewed your inquiry from before, which is replicated below.

kuntalroy86 said:

I am using eZ430 RF2500 kit.  I am able to get the RSSI value in the console(of the GUI provided) of Temperature monitoring program. My problem is to display these RSSI values with respect to time. So is it possible to display the time as well along with the RSSI. In short, is time stamping possible?

Hi...Firstly thanks a lot for your concern, I guess  my problem could be solved with ur valuable suggestions.

So now ,I want to display the time information, along with the RSSI values. It can be in the given GUI or any other user interface.

My aim is, to display each received RSSI values with their respective time..and if any received packet is missed, then the RSSI value of that missed packet will not be available .Thus, for that second,the display where RSSI value is displayed will remain blank, but the time will be displayed. Thereby, informing the user ,that particular second, the packet was missed..

Please email me at Kuntalroy86@gmail.com. If i am not clear in explaining my requirements....

Thanks a lot for your time..

Regards,

Kuntal Ray

So, are you wanting to receive RSSI information from a remote node?
And timestamp that information?

I guess I was thinking you were reading RSSI information from the local CCxxxx device and timestamping that information.

Hi,

  I want to time stamp the RSSI value of the signals received by the local RF2500 ,transmitted by the remote RF2500device.

Is it clear?

Thank You

Regards,

Kuntal Ray

Yes, I believe that is clear.

The Sensor Demo application in SLAC139B, uses TimerA to create a 1 sec timer interrupt by using the internal 12KHz oscillator, setting the TimerA compare register to 12000.  This will then generate an interrupt every 12000Hz/12000 = 1Hz.
If a 1 second granularity is all you need for your application, then inside the timer interrupt, I would suggest modifying some counters for seconds, minutes and hours.  You can add these as global variables in the demo_ED.c file.
When the linkTo() performs a reading, I would suggest modifying it to add to the message the hour, minute and seconds value and send that entire message.

If you desire milisecond granularity, then modify the TimerA compare register to 12, which would result in a timer tick every 12000Hz/12 = 1000Hz.  However, keep in mind, this will drastically impact your power consumption if the entire system is meant to go to a low power mode after every reading.
The reason for this increase in power draw is due to TimerA waking up every 1 msec, rather than every 1 sec.

You will need to increase the msg[] buffer to include bytes for the hour, minute and second parameters.  1 byte per value would be sufficient, considering 0<=hour<=23, 0<=minute<=59 and 0<=second<=59.

For the Wireless Sensor Monitor in SLAA378B, it would be TimerB.

I would think that you could add the Real-Time-Clock software that runs on the 32,768Hz ACLK to your Access Point code. You could then time tag the received messages. You should be able to find the code in the MSP430 code examples.

Scott