I am having an interesting problem with serial communication on the MICAz
motes. The problem is that certain packets will not be received correctly. I
have been unable to tell why a packet us unable to be received from the
error message: serial@/dev/ttyUSB1:57600: bad packet.
This is my current setup:
I wrote a mote program that will recieve a packet with a 16 bit number. It
will then send back that number along with the data: FF AA FF 55 FF AA FF
55 FF AA FF 55 FF AA FF 55. I use the UARTComm module to send and receive
the packets. The AM number for the request packet is 8 and the data response
packet is 9. The address I send the data response packet to is
TOS_UART_ADDR.
I also wrote a Java program. It sends the packet to the mote with the 16 bit
number. It waits for one second to receive the data response packet. Once
the packet is received, it will increment the 16 bit number and request the
new data line. This loop starts with line number EEPROM_LOGGER_APPEND_START
and ends before EEPROM_LOGGER_APPEND_END. If the packet was not received in
the timeout period then the request for the data line is sent again. The
re-request will happen up to 25 times before it gives up and goes to the
next number.
I am expecting the packet should be received before 25 retries but this is
not happening all the time. Most of the data lines I am able to receive
without a problem. These are the first few numbers I am unable to receive:
120, 266, 269, 355, 522, 525, 590, 680, 683, 685, 686, 778, 781, 793, 794,
796, 799. If I change the data in the responce the bad packets will happen
on different 16 bit numbers.
I am requesting help in finding why this problem is occurring. Suggestions
to narrow down the problem would be much appreciated.
--
Joseph A. Lutz
Computer Science Major
[EMAIL PROTECTED]
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