Logical Design of Digital Systems

Experiment $1$: data$-$traffic in digital circuits

Q$19$: What are the inputs WA$,$ WB$,$ RA and RB for?

Q$20$: Can a data bus be used as bidirectional bus? Explain your answer.

Q$21$: Derive the input series, which stores the following $4-$bit words in the register and outputs them afterwards. $($Noted: You are not allowed to do lab without completed the following table$)$

$\backslash$table$[[$D$[1.\mathrm{.}4],$GW$,$WB$,$WA$,$RA$,$RB$,$GR$,$Q$[1.\mathrm{.}4]],[1111,,,,,,,],[0000,,,,,,,],[1010,,,,,,,],[0011,,,,,,,]]$