MSP430 Micro-controller Multiple Choice Questions on “Architecture”.
1. In MSP430, the size of the status register is ________
a) 1 byte
b) 2 bytes
c) 1 bit
d) 2 bit
Answer: b
Clarification: In MSP430, the size of the status register is 2 bytes. The bits of the status register consists of the C flag, Z flag, N flag, GIE flag, CPU off, OSC off, SCG0, SCG1, V flag and 7 reserved bits.
2. Which of the following bit/s of the status register that allows the microcontroller to operate in its low power mode?
a) Z
b) Reserved
c) CPU off
d) N
Answer c
Clarification: The CPU off bit, OSC off bit, SCG0 bit, SCG1 bit of the status register are used to allow the microcontroller to operate in its low power mode.
3. What is actually done to improve the efficiency of a RISC processor?
a) instructions are reduced
b) they have two or more processors inbuilt connected between
c) they have many instructions that are interrelated to each other
d) they have one or more registers hard wired to the commonly used values
Answer: d
Clarification: To improve the efficiency of the RISC processor, the registers that are hard wired to commonly used values are used instead of other ones.
4. To improve the efficiency of an MSP430 based microcontroller, for one register
a) there is only one value for all addressing modes
b) there are two values for each addressing mode
c) there are 2 values for four addressing modes
d) there are 4 values for four addressing modes
Answer: d
Clarification: In MSP430, there are namely 4 addressing modes. So the main advantage of this controller( which basically increases its efficiency )is that for one register their exists 4 different values for 4 different addressing modes of the controller.
5. Their are_______________ number of emulated instructions found in the MSP430?
a) 4
b) 8
c) 16
d) 24
Answer: d
Clarification: The constants CG1 and CG2 are combined together to give 27 native instructions. These instructions are further converted into 24 emulated instructions. So, there are 24 emulated instructions found in an MSP430 based controller.
6. .w form is used for operations
a) that uses bytes
b) that uses words
c) that uses both
d) that uses none
Answer: c
Clarification: .w form is used for operations, that uses both bytes and words for operations.
7. Pre increment addressing is available in MSP430?
a) true
b) false
c) cant be said
d) depends on the conditions
Answer: b
Clarification: MSP430 supports only post increment addressing. For performing pre increment addressing, we require some special functions that accomplish that work.
8. Which out of the following is a correct emulated instruction?
a) ADC(.B) dst
b) ADD(.B) src,dst
c) ADDC(.B) src,dst
d) AND(.B) src,dst
Answer: a
Clarification: “ADC(.B) dst” this is emulated to “ADDC.B #0,dst” hence this is an emulated instruction. The emulated instructions use core instructions combined with the architecture and implementation of the CPU for higher code efficiency and faster execution.
9. dadd instruction can act as _____________
a) valid BCD addition
b) valid adder with carry
c) all of the mentioned
d) none of the mentioned
Answer: a
Clarification: Dadd instruction can act as a valid BCD addition instruction if the numbers are initially in BCD state(0-9).
10. Which of the following instructions don’t affect the status bits?
a) bis
b) bic
c) bis & bic
d) none of the mentioned
Answer: c
Clarification: bis and bic don’t affect the bits of the status register.