Saurabh Moghe

SMAC data loss

Discussion created by Saurabh Moghe on Jul 30, 2008
Latest reply on Aug 5, 2008 by Mads Westergreen
I am using SMAC. The code is generated using Beekit, the accelerometer project in the SMAC section. The ADC in that example is 8-bit and the 3 bytes of data that is transferred from the Accelerometer SRB to the SRB that is connected the PC.

Only thing I have changed is the ADC is now 10bits so 6 bytes are transferred from the Accelerometer SRB to the SRB that is connected the PC.

When I collect the data on the PC using a hyperterminal program I can see that there is some loss of data. To investigate it further I changed the sending code on the Accelerometer. Instead of reading the accl values and sending them to the other SRB I worte a function that has three 16bit unsigned variables first with value  0, second with value 100 and  third with value 200. I have put all these variables in the transmit buffer. The transmit buffer being 8bit unsigned, I had to split the the variable, with MSB put in the buffer first followed by the LSB.

I have captured the bytes on the PC using a hyperterminal program for atleast 90seconds. By analyzing the received data I can see that I don't get the values in series.i.e I get value 0 100 200. then I get 2 102 202. This shows that I encounter packet loss.

I tried this on the 8-bit code as ws generated using Beekit. I just modified the sending part as above but only  for 8-bit values. This also gave me the same results. I do see data loss.

Has any one observed  data loss in using SMAC for communication. My application being critical I can't afford data loss. Does MAC(802.15.4) have data loss too.

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