| 1. |
for i/o of 8255,if -----, the word is taken as a bit set/rest word |
| A. | D7=1 |
| B. | D7=0 |
| C. | D0=1 |
| D. | D0=0 |
| Answer» B. D7=0 | |
| 2. |
on activation of ----, 8255 loads data from the input port lines into the input buffer of that port |
| A. | STB# |
| B. | IBF |
| C. | OBF# |
| D. | none of these |
| Answer» B. IBF | |
| 3. |
8255 has three ----parrallel port |
| A. | 8bit |
| B. | 16bit |
| C. | 32bit |
| D. | 64bit |
| Answer» A. 8bit | |
| 4. |
in ----, bidirectional data transfer is possible |
| A. | mode 0 |
| B. | mode1 |
| C. | mode2 |
| D. | BSR |
| Answer» C. mode2 | |
| 5. |
walkie-talkie is an example of …..serial communication |
| A. | Simplex |
| B. | Half duplex |
| C. | Full Duplex |
| D. | none of these |
| Answer» B. Half duplex | |
| 6. |
Transmission through telephone lines is an example of….serial commuincation |
| A. | Simplex |
| B. | Half duplex |
| C. | Full Duplex |
| D. | none of these |
| Answer» C. Full Duplex | |
| 7. |
Asynchronous serial communication involves |
| A. | start bit |
| B. | stop bits |
| C. | character data |
| D. | all of these |
| Answer» D. all of these | |
| 8. |
to configure 8255 with port A output,Port B input port C lower output and port C upper input |
| A. | Mov al,0AFH |
| B. | mov al,0AEH |
| C. | mov Al,0CEH |
| D. | Mov A,0AAH |
| Answer» B. mov al,0AEH | |
| 9. |
A high on ---line indicates that the buffer register is empty |
| A. | TXRDY |
| B. | TXE |
| C. | TXC# |
| D. | both B and C |
| Answer» B. TXE | |
| 10. |
Adc 0808 uses ----technique |
| A. | Successive apraximation |
| B. | single step |
| C. | dual slope |
| D. | flash converter |
| Answer» A. Successive apraximation | |
| 11. |
the signals provided by ADC are |
| A. | SOC |
| B. | EOC |
| C. | ALE |
| D. | all of these |
| Answer» D. all of these | |
| 12. |
Flash ADC consist of….converters |
| A. | 2^n |
| B. | 2^n -1 |
| C. | 2^n +1 |
| D. | none of these |
| Answer» B. 2^n -1 | |
| 13. |
8253/54 has ----independent timers/counters |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 14. |
8253/54 timers can be programmed in---modes |
| A. | 1 |
| B. | 3 |
| C. | 6 |
| D. | 5 |
| Answer» C. 6 | |
| 15. |
in mode 0 of 8253/54 ----disables counting |
| A. | gate=1 |
| B. | gate=0 |
| C. | wr#=1 |
| D. | wr#=0 |
| Answer» B. gate=0 | |
| 16. |
8253/54 has c----command that allows the user to check the count value programmed mode and current status of the counter |
| A. | write back |
| B. | write ahead |
| C. | read ahead |
| D. | read back |
| Answer» D. read back | |
| 17. |
for mode 3 of 8253/54, if the count is odd the output will be high for--- |
| A. | 2/(n+1) |
| B. | (n+1)/2 |
| C. | 2/(n-1) |
| D. | (n-1)/2 |
| Answer» B. (n+1)/2 | |
| 18. |
EOC means |
| A. | End of Conversion |
| B. | Enable output conversion |
| C. | error of conversion |
| D. | none of these |
| Answer» A. End of Conversion | |
| 19. |
ADC 0808 is ----- pin IC |
| A. | 40 |
| B. | 20 |
| C. | 24 |
| D. | 28 |
| Answer» D. 28 | |
| 20. |
ADC 0808 operates on single ---- power supply |
| A. | 5V |
| B. | 10V |
| C. | 15V |
| D. | 20V |
| Answer» A. 5V | |
| 21. |
8255 has -------- i/o pins |
| A. | 28 |
| B. | 26 |
| C. | 24 |
| D. | 22 |
| Answer» C. 24 | |
| 22. |
8255 has three ----parallel ports |
| A. | 8 bit |
| B. | 16 bit |
| C. | 32 bit |
| D. | 64 bit |
| Answer» A. 8 bit | |
| 23. |
In 8255 ,BSR means ----- |
| A. | bit set/reset |
| B. | byteset/reset |
| C. | binary set/reset |
| D. | none |
| Answer» A. bit set/reset | |
| 24. |
BSR mode is used to set or reset the bitsin |
| A. | portA |
| B. | portB |
| C. | portC |
| D. | portD |
| Answer» C. portC | |
| 25. |
8255 has ----i/o modes |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 8 |
| Answer» B. 3 | |
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