Specifications

CONSTRUCTION
our other Indian languages, we cannot
manage to use even a simple font within
this 8 x 8 matrix (which needs one byte
per line or 8 bytes per character). The
smallest size in Indian language requires
a 12 x 12 matrix, and hence we need 1.5-
byte space horizontally and a total of 12
x 1.5 = 18 bytes space for each letter.
Further, if one wants better looking fonts,
for instance like the standard Time Ro-
man of English, more dots need to be
shown, and hence the character slot size
will be even greater than 12 x 12 dots.
In the proposed scheme a 12 x 12 dot
font size is used, both for the dedicated
microprocessor based display scheme as
well as for the PC based scheme.
Since we have already specified codes
for all the
text char-
acters in a
manner as
shown in
Table I, it
is now re-
quired to
put the
dots for
each code
into the
character
generator.
Thus, we
specify text
only by its
codes. For
example,
for English
letter ADD,
the code is
41, 44, 44.
The actual
dots are
available
within the
character
generator,
and hence
the space
needed for
storing text
is just lim-
ited to the
characters
or strokes.
But, in
other
schemes
generally
employed
in other
software,
the text is
stored as
graphic
patterns
and hence
quite a
large
amount of memory is needed.
Now take a look at the keyboard—
row by row. The top row contains numer-
als. Next row starts with ‘Q’ and ‘q’ (in
English) and is used for ‘PHA’ and ‘u’ hook
in Hindi with and without shift key press-
ing, respectively. So, these have the same
ASCII equivalent codes, i.e., 51 hex and
71 hex, respectively.
Fig. 1(a): Schematic diagram of 8085 microprocessor based multilingual display system (memories and decoder portion)
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