How do you determine the ranges? Please explain step by step A microprocessor (u

Question

How do you determine the ranges?
Please explain step by step

A microprocessor (up) uses a 16-bit address bus and an s bit data bus, The address bus lines are labeled AIS to As, where A15 is the most significant address bit and A is the least significant address bit. The microprocessor generates an active-low address strobe (AS) at the beginning of memory access cycle 1e indicate that a valid address has been placed The signal assered for the entire memory access cycle on the address bus In a certain application of the up, the three most significant address bits (A s are used inputs lo a 3-of-s decoder to generate chip select signals (CSr CST). The chip-select signals are used to an EPROM memory device whose address lines are tied directly address lines (Air As) of the up. The EPROM's output lines are enabled whenever its enable input (EN) is pulled low. A figure of the microprocessor described above and the decoder truth table are shown on the opposite page. The range of addresses (expressed in hevadecimal to which the EPROM in the figure will Tespond is most nearly:

Explanation / Answer

ANSWER:

To find out the address range of a block means that we have to find out at what address range the data from the corresponding block (EEPROM in this case) comes out. This memory will be activated if the corresponding chip select (CS) is low. Since CS4 is connected to the memory, the most significant three address bit have to be 100 (A15-A13). So, this memory will always be accessible when A15-A13 is 0b100. So, for binary addresses of the form 100x_xxxx_xxxx_xxxx (here x represent a don't care, meaning we do not care about it's actual value), the shown memory is activated.

The maximum value of this expression will be 1001_1111_1111_1111, i.e. 0x9FFF.

The minimum value of this expression will be 1000_0000_0000_0000, i.e. 0x8000.

So, the address range is 0x8000-0x9FFF (option C)

Related Questions

Navigate

• Browse (All)
• Browse H
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.