$2.$ c$.$ A multi$-$processor system contains two microprocessors which are mounted on separate printed circuit cards. The clock and data signals pass through a line driver when they leave one card and a line receiver when they pass onto the next. The combined delay of the driver and receiver may vary between $7$ ns and $11$ ns $.$ New data values appear at DA on the falling edge of CA with a propagation delay of $5$ to $25$ ns $.$ Data is clocked into $\backslash (\backslash$mu $\backslash$mathrm$\{$PB$\}\backslash )$ on the rising edge of CB with a setup time of $6$ ns and a hold time of $13$ ns $.$ If the clock, CA $,$ is a symmetrical square wave, calculate its maximum frequency. Draw the timing diagram of the signals $\backslash (\backslash$mathrm$\{$CA$\},\backslash$mathrm$\{$CB$\},\backslash$mathrm$\{$DA$\}\backslash )$ and DB showing the important delays on this diagram.

$(6$ Points$)$