If you are trying to create a test vector to feed into a block that needs a tag named "length", you can use a Vector Source. That block allows you to define a vector of data along with tags.
On Sun, Jun 21, 2020 at 6:38 PM George Edwards <[email protected]> wrote: > Hello, > > New to gnuradio and I am making an OOT CRC8 module to take a tagged bit > stream (1's and 0's) and generate the CRC and attach the CRC to the end of > the data and pass it on to the next block. Also, I am encapsulating both > the generator and check sum in same block using a boolean variable "check" > to determine operation. > > In QA test I get the following error: > gr::log :FATAL: my_crc8_bb0 - Missing a required length tag on port 0 at > item #0. > thread [thread-per-block[1] < block my crc8_bb(2)>] Missing length tag > > I modified the QA test vector by writing the length of the input string of > 1's and 0's as the first element in the input data array, but it gave the > same error as typed above. > > Questions: > Q1. How do I write in the input test vector, or what do I add to what I > already have to make the module aware of the tag length? > > Q2. In the my_crc8_bb_impl.cc file in the tagged stream method, I > specified the tag name as "packet_len". In the signal processing in this > .cc file, I assume the value of packet_len is available to me for use as a > parameter and I used it. Are there some other things I need to do in this > "my_crc8_bb_impl.cc file" to make the module more aware of input tagged > stream data (maybe I am not binding "packet_len" properly)? > > I greatly appreciate any help! > > Regards, > George >
