Testbook TestSeries - Vertical Microprogramming

Question

A vertical microprogrammed control unit has 16 conditional flags 250 signals and size of control word is 24 bits, size of the control memory in Kbytes is ______.

Comments

I am getting 12 KB :/

---

12KB is correct

---

@minipanda : can u refer any place from where i can refer this topic or shall i go for morris mano

---

arvin check my comments https://gateoverflow.in/1061/gate2004-67

Answer 1

Control word = conditional flag bits + controls signal + next micro instruction address

24 = 4 + 8 + next micro instruction address

=> next micro instruction address= 24-12=12.

Hence there are 2¹² micro instructions in the control memory.

Each of the micro instructions occupy 24 bits i.e. one control word for each of them.

So total size of control memory = control word size* no. of micro instructions = 24 bits * 2¹² = 3B * 2¹²= 3*4 * 2¹⁰ B = 12 KB.