The check sum method of testing a ROM: indicates if the data in more than one me

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Question
The check sum method of testing a ROM:
Options
A. indicates if the data in more than one memory location is incorrect.
B. provides a means for locating and correcting data errors in specific memory locations.
C. allows data errors to be pinpointed to a specific memory location.
D. simply indicates that the contents of the ROM are incorrect.

Correct Answer

simply indicates that the contents of the ROM are incorrect.

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3. Refer the given figure. The outputs (Q0?Q3) of the memory are always LOW. The address lines (A0?A7) are checked with a logic probe and all are indicating pulse activity, except for A3, which shows a constant HIGH, and A7, which shows a constant LOW; the select lines, are checked and shows pulse activity, while indicates a constant HIGH. What is wrong, and how can the memory be tested to determine whether it is defective or if the external circuitry is defective?
Options
A. One of the inputs to the active-LOW select AND gate may be stuck high for some reason; take both select lines LOW and check for pulse activity on the outputs, Q0?Q3. If the outputs now respond, the problem is most likely in the program or circuitry driving the select lines.
B. The problem appears to be in the two address lines that never change levels; the problem is probably in the program driving the memory address bus.
C. The output buffers are probably defective since they are all tied together; the common input line is most likely stuck LOW. Change the output buffer IC.
D. Since no data appears to be getting through to the output buffers, the problem may be in the X decoder; change the X decoder IC.

5. What is the principal advantage of using address multiplexing with DRAM memory?
Options
A. reduced memory access time
B. reduced requirement for constant refreshing of the memory contents
C. reduced pin count and decrease in package size
D. It eliminates the requirement for a chip-select input line, thereby reducing the pin count.

6. The device shown in the given figure is checked with a logic probe and the output is HIGH.
Options
A. The device is working properly.
B. For the input conditions shown the output should be LOW; the input is shorted to ground.
C. For the input conditions shown the output should be neither HIGH nor LOW; the device is shorted to .
D. The device is probably alright; the problem is most likely caused by the stage connected to the output of the device.

7. Select the statement that best describes Read-Only Memory (ROM).
Options
A. nonvolatile, used to store information that changes during system operation
B. nonvolatile, used to store information that does not change during system operation
C. volatile, used to store information that changes during system operation
D. volatile, used to store information that does not change during system operation

9. Select the statement that best describes the fusible-link PROM.
Options
A. user-programmable, one-time programmable
B. manufacturer-programmable, one-time programmable
C. user-programmable, reprogrammable
D. manufacturer-programmable, reprogrammable

10. The RAM circuit given below is suspected of being bad. A check with a logic probe shows pulse activity on all of the address lines and data inputs. The / line and inputs are forced HIGH and the data output lines are checked with the logic probe. Q0, Q2, and Q3 show a dim indication on the logic probe; Q1 indicates a HIGH level on the logic probe. What, if anything, is wrong with the circuit?
Options
A. The Q0, Q2, and Q3 output lines are open; the chip is defective.
B. The Q1 line appears to be shorted to V_cc; replace the chip.
C. The outputs should be active only when the / line is held LOW, so the circuit is behaving normally considering the fact that the line is HIGH.
D. The EN input should be forced HIGH and the outputs rechecked; if they are still giving the same indications as before, then the three outputs are definitely open and the IC will have to be replaced.

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