Digital Electronics Objectives Part 20
381 . In 8355, the ROM is organized as 2048 words of 8 bits each.
382 . When a bit is O in a DDR, it makes the corresponding port pin an input on the other hand, a 1 bit program a output pin.
383 . Status register in the 8156 contains information about the timer and the port.
384 . Status register in the 8156 is read with IN 20 H.
385 . A pair of 2114s can store 1024 words of 8 bit each.
386 . The contents of the command register are 23 H. the port C is an input port.
Question 387 and 388 refer to program below:
A program segment is given below:
MVI A,2 BH
OUT 24 H
MVI A,86 H
OUT 25 H
387 . The terminal count in decimal form is 1579.
388 . Single pulse is produce by times.
389 . An 8156 has A15 connected to its CE input. A14 to A8 are unconnected, and AD7 to AD0 are connected. Ignoring shadows, 8000 H —- 80 FFH are the RAM locations.
390 . In the above case the port addresses 80 H TO 85 H.
Question 391 and 392 refer to Fig. 60.
The 8156 of Fig. 60 has RAM locations from 2000 H to 20 FFH.
391 . 8 zone bits are there.
392 . If all bubbles are removed, the new RAM locations are FFOOH —FFFFH.
393 . The stack is a specialized temporary sequential access memory during push and pop
instructions.
394 . The generic microprocessor contains a zero and a carry flag. These are located on the status register.
395 . In the generic microprocessor machine cycle time period is shorter than instruction cycle time period.
Question 396 to 398 refer to Fig. 61.
396 . The contents of stack location 2019 H after the call operation will be 00100000.
397 . The contents of stack location 2108 H after the call operation will be 00000111.
398 . The contents of the program counter after the call operation will be 30 FOH.
399 . The contents of the program counter after the call operation point to the first instruction on the subroutine.
400 . Flow charts that contain decision symbol do not represent straight line program.
