Short Answer #$2[20$ marks$]$

For this question you will be asked to design a memory decoder circuit and present one memory$-$block$/$IC from that design.

a$)$ You are building an application specific digital device $($ASDD$)$ that needs to hold $256$bytes of data $(8-$bits wide$)$ in a volatile memory. The only available memory units are $32-$bytes $(8-$bits wide$).$ Design a memory decoder for this custom digital system by deriving the logic expressions. From the memory user's perspective, they should be able to use $256-$bytes as a contiguous memory block.

For this part,

i$)$ design only the ASDD memory$-$block$/$IC decoder $($do not design the memory decoder inside each memory$-$block$/$IC$),$

ii$)$ clearly state how many bits are required for memory$-$block decoding,

iii$)$ clearly state how many bits are required for addressing each block, and

iv$)$ clearly state how a user would access address $(100)10$ in memory $($show decode$-$bits:address$-$bits$).$

Your decoder must be designed using digital design methodology from lecture and labs $($truth table, k$-$map, and minimized Boolean functions$).$ You may not use predesigned integrated circuits elements for the decoder $($e$.$g$.,$ MUX, Encoder, Decoder, etc.$).[10$ marks$]$

b$)$ Based upon part$-$a$,$ very neatly draw one specific memory$-$block$/$IC of your memory design's digital circuit. The specific memory$-$block$/$IC contains address $(100){?}_{10}.$ If you did not complete part$-$a or cannot determine which memory$-$block$/$IC contains the specified address then you may use block$-0$ with a $4$ mark deduction.

For this part,

i$)$ clearly state the memory$-$block$/$IC that contains address $(100)10($remember ${?}^2$ that memory$-$block ICs are labelled starting at $0),$

ii$)$ for the individual memory IC you shall represent it as a functional unit$/$block with clearly labelled pins that show: address pin$($s$),$ enable pin$($s$),$ clock, read$/$write pin$($s$),$ data input$($s$),$ data output$($s$)($Do not draw the memory ICs at the flip$-$flop level$),$ include the digital circuit $($gate level$)$ that the decoder from part$-$a uses to enable this block$/$IC$.$

Cleary label all inputs and outputs. You may assume the complement of any variable is readily available. $[10$ marks$]$