Specifications

CONSTRUCTION
her vote.)
7. Now, the voter can
cast his/her vote by press-
ing the appropriate key-
board switch allocated to
the candidate of his/her
choice. The acceptance of
the vote by the system is
acknowledged by a beep
sound as well as the dis-
play of the ‘
’ symbol in
the display and ‘off’ condi-
tion of LED D4.
8. Steps 6 and 7 have
to be repeated for casting
a fresh vote.
9. If the count of any
particular candidate’s
votes (count) is needed to
be displayed, press ‘dis-
play’ switch and then the
switch corresponding to
the specific candidate on
the keyboard.
10. Reset the system.
11. Switch ‘off’ the sys-
tem.
Software description
The system programs are
stored in the EPROM. The
entire software is divided
into five modules, namely,
booting, display, clearing
memory, counting, and
keyboard.
The operation of each
module can easily be un-
derstood with reference to
the flowcharts.
Booting. This module
initialises the stack pointer
8255 PPI, verifies the
password entered via the
keyboard, and initialises the interrupts.
Display. This module uses the inter-
rupt service subroutine at RST 7.5. This
is used for displaying the count (votes)
polled by each of the candidates.
Clearing memory. This module is in-
voked via interrupt service subroutine RST
5.5. It is used to clear the count memory.
Counting. This module uses the in-
terrupt service subroutine RST 6.5. It ac-
tivates the microprocessor to accept only
one vote. If the count of any candidate
exceeds ‘9999’, it will produce a continu-
ous beep sound and display ‘
’, and then
onwards the system will not be ready for
can be changed by adjusting some values
in the system software.) At present, only
three-digit password is used. If the pass-
word digits entered via keyboard equal
the password stored in the EPROM, LED
D2 glows to give access for operation of
the machine.
4. If the entered password is incor-
rect, press RESET button (S49) and pro-
ceed again from the first step.
5. Clear the previous content of count
memory by pressing ‘clear’ button (S52).
Clearance of memory is indicated by sym-
bol ‘:’ in the display.
6. Now press ‘count’ switch S51. The
display of symbol ‘[’ and the glowing of
LED D4 would mean that the system is
ready for accepting one vote. (Please note
that the ‘count’ switch is placed
under the control of electoral staff so
that it is satisfied with the identity of the
voter before allowing him/her to cast his/
TABLE II
Start Address Map of Hardware Interrupts
Address (hex) Interrupt
0024 TRAP
002C RST 5.5
0034 RST 6.5
003C RST 7.5
Fig. 2: Flow chart for the various software programs
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