Digital Electronics/Circuits Multiple Choice Questions on “Programmable Read Only Memory -1”.
1. The time from the beginning of a read cycle to the end of tACS/tAA is called as ____________
A. Write enable time
B. Data hold
C. Read cycle time
D. Access time
Answer: D
Clarification: The time from the beginning of a read cycle to the end of tACS/tAA is called as access time. It is the time in which data is fetched from the storage.
2. Why did PROM introduced?
A. To increase the storage capacity
B. To increase the address locations
C. To provide flexibility
D. To reduce the size
Answer: C
Clarification: In order to provide some flexibility in the possible applications of ROM, PROM is introduced. PROM stands for Programmable ROM, in which the ROM is programmed by the user.
3. Which of the following is programmed electrically by the user?
A. ROM
B. EPROM
C. PROM
D. EEPROM
Answer: C
Clarification: Programmable ROMs can be programmed electrically by the user but can’t be reprogrammed. EEPROMs can be electrically erased and re-programmed by the user.
4. PROMs are available in ___________
A. Bipolar and MOSFET technologies
B. MOSFET and FET technologies
C. FET and bipolar technologies
D. MOS and bipolar technologies
Answer: D
Clarification: PROMs (Programmable ROMs) can be programmed electrically by the user but can’t be reprogrammed. PROMs are available in both bipolar and MOS (Metal Oxide Semiconductor) technologies.
5. The bit capacity of a memory that has 2048 addresses and can store 8 bits at each address is ___________
A. 4096
B. 16384
C. 32768
D. 8129
Answer: B
Clarification: 1 address can store 8 bits. Therefore, total capacity of a memory having n addresses = 8 * n.
Therefore, for 2048 addresses,
total capacity of a memory = 2048 * 8 = 16384 bits.
6. How many 8 k × 1 RAMs are required to achieve a memory with a word capacity of 8 k and a word length of eight bits?
A. Eight
B. Two
C. One
D. Four
Answer: A
Clarification: RAM stands for Random Access Memory in which any memory address can be accessed in any order. It requires word of length 8 bits. So, one word needs of 1 bit and 8 bit requires 8 bits.
7. Which of the following best describes the fusible-link PROM?
A. Manufacturer-programmable, reprogrammable
B. Manufacturer-programmable, one-time programmable
C. User-programmable, reprogrammable
D. User-programmable, one-time programmable
Answer: D
Clarification: The fusible-link PROM is user programmable and one time programmable. It means that a written program can not be reprogrammed. EPROMs can be erased and re-programmed.
8. How can ultraviolet erasable PROMs be recognized?
A. There is a small window on the chip
B. They will have a small violet dot next to the #1 pin
C. Their part number always starts with a “U”, such as in U12
D. They are not readily identifiable, since they must always be kept under a small cover
Answer: A
Clarification: An ultraviolet erasable PROMs have small window on the chip with black marked. Such type of PROMS are called EPROMS which are cleared by exposing it to UV radiation. They are re-programmable.
9. Which part of a Flash memory architecture manages all chip functions?
A. Program verify code
B. Floating-gate MOSFET
C. Command code
D. Input/Output pins