Expand the memory unit to a 32x4 RAM using two 7489ICs ( you might use the HM6116A120 chip for the Multisim Program Simualtion). Use the CS inputs to select between the two ICs. Note that since the data outputs are 3-stated, you can tie pairs of terminals together to obtain a logic OR operation between the two ICs. Test your circuit by using it as a ROM simulator that adds a 3-bit number to a two-bit number to product a 4-bit sum. For example, if the input of the ROM is 10110, then the output is calculated to be 101+10 = 0111. (The first three bits of the input represents 5, the last 2 bits represent 2, and the output sum is binary 7.) Use the counter to provide four bits of the address and a switch for the fifth bit of the address.