ELET2100 (EL21C) - MICROPROCESSORS I
COURSE TEST #1 - WEDNESDAY 18th OCTOBER 2006
Time:
(3:00 - 4:00 )PM
( 1 ) Describe the effects on
the Flags when the following instructions are executed.
Before each instruction, assuming
all Flags = 0 (reset) and register contents are:
A = DAH; B = 06H; C = 9CH
(i) MOV B,
A
(ii) DCR C
(iii)
ADD B
(iv) IN 22H
(v) RAL [5]
( 2 ) How
many bytes of memory does the program below occupy ?
STA 2000H
OUT 15H
MVI A, 20H
STA 2050H
NOP
IN 14H [2]
( 3 ) If the A-register = C7H
and the instruction OUT 21H is executed, what is the
binary
status on the Address and Data busses ? [3]
( 4 ) List the hardware
Interrupts on the 8085 in order of priority. [2]
( 5 ) Where does the RST 6
instruction jump ? [1]
( 6 ) In Figure 1 below, what
address values (range) would enable the output of the
OR-gate labeled “A” ? [3]
( 7 ) If
registers BC =
sequence of
instructions below ?
PUSH B
PUSH H
PUSH D
POP B
POP D
POP H [3]
( 8 ) Write
an Assembly Language (
memory
location 2011H. [1]
( 9 ) Write
an
memory
location 2011H in question (8) above. What is the new
contents of memory
location
2011H ? [4]
(
10 ) The 8155 IC contains 256-bytes of RAM, 3-I/O ports and a
Timer/Counter. What
is the
maximum value that can be loaded into the Timer/Counter ? [1]
(
11 ) If the Timer/Counter is driven by a 100 KHz clock signal, how
long will it take
the
Timer/Counter to reach its terminal count if it was pre-loaded with the
value 1234H ? [1]
( 12 ) The SDK-85 kit in the lab is
equipped with:
( i ) 8-LED’s
on Port 00
( ii
) 8-switches on Port 01
The switches are set as: (msb) 00010101;
[201F] = 3DH; [2020] = 06H; [2021] = FEH.
Assuming the ports are initialized and the
program below is executed:
IN 01H
ANI 0FH
STA 2020H
RLC
OUT 00H
LXI H,201FH
AND M
STA 2021H
HLT
( a ) What is stored in locations
201FH; 2020H; 2021H ? [3]
( b ) Which LED’s are ON ? [1]
Bonus mark:
How many steps would you walk up from the ESL lab to the water-cooler ? (to ± 2 steps).
Maximum mark = 30