Data capture during disk write is working, next to explore pathological cases

INPUT AND OUTPUT TEXT FILES CREATED

I set up a file stream.txt to hold the words to send to my bit capture state machine, each line consisting of 20 discrete bits coded as the ASCII characters 0 or 1. I set up an initial line of all zeros to reflect the end of the preamble and then the sync word pattern as the next line. Following that I coded 321 words of input to capture the words that would be transmitted if the disk controller were writing a full 321 word sector. 

Another file, got.txt, was written by the testbench under simulation, storing away each word as it is captured by my state machine. The output matched what I intended to be captured.

SOME ERROR TESTING COMPLETED SUCCESSFULLY

I set up some input words with incorrect error detection code bit patterns and these indeed led to the state machine locking into the error state. As well I attempted various lengths of preamble and ensured that the state machine still properly captured the sector's worth of data whether it was shorter or a bit longer than the target duration.

REMAINING TESTING FOR TOMORROW

I am going to verify the operation in various conditions:

• Sync word is malformed
• writegate turned off prematurely
• writegate turned off in mid word
• writegate asserted before sector starts