ROM Memory Page total $59$ pts

$1\mathrm{.}3$ Now, show to Miss Bruin, how Miss Trojan would have placed the $5$ chips $($before programming

them with the required content, of course$)$ and connected them together. Let's not use a decoder this

time. You use random logic $($AND$/$OR$/$NAND$/$NOR$/$Inverter$,$ etc..$).$

Since we $($the Trojans$)$ are aware of natural boundaries, we have

$(\frac{2}{3}\frac{?}{4})$ choices for placing

the $16$ x $8$ ROM in the $32$ KB map. For each of these choices, we further have

$(\frac{2}{3}\frac{?}{4})$ choices

for placing the pair of $8$ Kx $4$ ROMs in the $32$ KB map. Altogether we have

$(\frac{2}{3}\frac{?}{?}\frac{4}{5}\frac{?}{?}\frac{6}{7}\frac{?}{8})$

choices. All these choices are of course meaningful if we have not yet programmed the ROMs. We

decide the mapping and then program the $5$ ROM chips making up the $32$KBRROM. I have provided

$6$ grids with $8$ rows. One is already completed. Delete extra grids and draw your choices over the grids.

Page total $8$ pts

All threa pagas total $183$ pts

$($

Memory width and depth expansion: We need to build a $32$ Kx $8$ ROM memory

$1\mathrm{.}1$ Given on the side and below is Miss Trojan's design solution using $8$ of $4$ KB ROMs.

$32Kx8=>32K$ is $2^{15}=>$ It receives $15$ address lines $A[14$:$0].$

Top $3$ lines $A[14$:$12]$ can be decoded using a $3-$to $8$ decoder to generate the

$8$ individual chip enables: $\frac{?}{\text{b}\text{a}\text{r}}(CE0)$ through $\frac{?}{\text{b}\text{a}\text{r}}(CE7)$ for the $84$ Kx $8$ chips.

$32Kx8=>32K$ is $2^{15}=>$ It receives $15$ address lines $A[14$:$0].$

Top $3$ lines $A[14$:$12]$ can be decoded using a $3-$to $8$ decoder to generate the

$8$ individual chip enables: $\frac{?}{\text{b}\text{a}\text{r}}(CE0)$ through $\frac{?}{\text{b}\text{a}\text{r}}(CE7)$ for the $84$ Kx $8$ chips.

$32Kx8=>32K$ is $2^{15}=>$ It receives $15$ address lines $A[14$:$0].$

Top $3$ lines $A[14$:$12]$ can be decoded using a $3-$to $8$ decoder to generate the

$8$ individual chip enables: $\frac{?}{\text{b}\text{a}\text{r}}(CE0)$ through $\frac{?}{\text{b}\text{a}\text{r}}(CE7)$ for the $84$ Kx $8$ chips.

These three pages form the actual assignmant to be complated and submitted on D$2$L$.$

$1\mathrm{.}2$ Miss Bruin found $5$ ROM chips: a $16$ Kx $8,$ two $8$ Kx $4$ and two $4$ Kx $8.$ She was not taught about

natural boundaries of address ranges and has arranged the five chips as shown on the next page and

programmed them with the needed content. Now we can not change the map. So$,$ you please

complete the design on the next page to suit. The $32$ Kx $8$ ROM $($if available as one chip$)$ would have

address pins and

data pins. A $32$ K range in hex spans from $0000$ Hex to

Hex. To complete the design on the next page, add missing labels, wires, and gates.