Digital Electronics Objectives Part 21
401 . The memory address of the last location of a 1 k byte memory chip is given as OFBFFH. The address of the first location is OF 800 H.
402 . Line 3 goes low if the input to the 2-to-8 decoder (74L8º138) is (A7 – A0)
See Fig. 62.
403 . Line 6 goes low if connection of A3 and A5 are interchanged. All other condition are same as in the previous question.
404 . Memory map of the memory shown in fig.63 is OFCOOH—OFFFFH.
Note: answer Q 405 to Q 414, assuming 12 bit microprocessor capable of addressing 256 K word memory.
405 . Memory word size for thin microprocessor is 18 bits.
406 . Length of the Accumulator is 12 bits.
407 . There are 18 bits lines in address bus.
408 . Length of stack Pointer is 18 bits.
409 . Length of instruction Register is 12 bits.
410 . Length of memory address Register is 18 bits.
411 . Length of Data Buffer Register is 12 bits.
412 . Length of program counter is 18 bits.
413 . Length of Temporary Register is 12 bits.
414 . 4096 I/O ports can be accessed in direct method.
415 . The number of non-zero states for a 16 bit binary D/A converter is 65,535.
416 . The number of non-zero states for a 16 bit BCD D/A converter is 9,999.
417 . The percent resolution of a 12 bit BCD D/A converter is 0.1001%.
418 . In a 8 bit A/D converter the reference voltage used is 10 V. the voltage represented by 10100001 is 6.314.
419 . The least change in output voltage of 12 bit binary D/A converter using 12 V refrence supply voltage is 0.00293.
420 . Contents of program counter specify the address of the next instruction to be executed.