IEEE Transactions on Consumer Electronics, Vol. 35, No. ... Department of Electronic and Electrical Engg.,. Loughborough University of Technology,.
IEEE Transactions on Consumer Electronics, Vol. 35, No. 4, NOVEMBER 1989
854
ALPHANUMERIC PERSIAN CHARACTERS USING STANDARD 16-SEGMENT DISPLAYS F. Farzin-Nia and M. S . Beg Department of Electronic and Electrical Engg., Loughborough University of Technology, Loughborough, Leics LE11 3TU, U.K.
ABSTRACT
The layouts for the contemporary Persian (Farsi) alphabet and numerals using readily available standard16-segment alphanumeric
displays have been designed. A 64-word ASCII character set is presentedwhich includes special symbols as well. INTRODUCTION
Today, the advance in the alphanumeric displays has resulted in their usage in a wide range of domestic and specialised areas. Computer peripherals, automotive instruments, general purpose display boards and toys are to name a few. However, a limitation faced in their utilisation is that they are primarily used to display Latin and Greek based languages such as English. This poses a problem for those places where people use other languages. One way to overcome this problem is to go for specially designed bar matrix layouts suitable for the specific language such as Chinese, Arabic or Greek as has been done earlier [l-31. But the cost of these newly designed and manufactured display modules is likely to make the final product more expensive than warranted. The other alternative is to use the readily available standard dot matrix or bar
Contributed Paper Manuscript received May 22, 1989
matrix modules wherever possible. However, in the case of certain languages, the resultant characters may not be as good as those resulting from specially designed and manufactured layouts for those languages. The possibilities of using 5x7 dot matrix for Japanese and Arabic alphanumeric characters have already been demonstrated earlier [4,5]. In this paper the display for the Persian characters has been implemented using commercially available 16-segment LED/LCD display modules which are basically meant for displaying English characters. The code converter that will be required here will be much simpler than that for a 5x7 dot matrix display. ORGANISATION
OF
THE
DISPLAY
SYSTEM
The alphanumeric display module that is to be used for Persian characters contains 16 almost equal-length segments, a decimal point (DP) and a colon (CO) giving a total of 18 elements. An example of such a module is the Hewlett Packard's HDSP-6300 161
-
- serial bitparallel data acts as an input to a character address decoder. The latter energises one of the 64 word lines WO, Wl, ..., W63 pointing to the required
A 6-bit character
0098 3063/89/02OO 0854$01 .OO 1989 IEEE
Nia and Beg: Alphanumeric Persian Characters Using Standard 16-Segment Displays
character. The ROM will need a maximum capacity of 64 x 18 = 1152 bits corresponding to the 18 elements in the display module. Fig. 1 shows a typical block diagram for displaying a single bar matrix character having 18 elements. SUGGESTED LAYOUTS
Since the Persian language has a total of 32 alphabet, the above mentioned organisation can accommodate the 32 alphabet, the 10 numerals and 22 specially selected symbols. It is to be noted, however, that many Persian alphabet take different shapes depending upon their position in a word. For instance I I (corresponding to the the letter 'HI in English) takes the form I 9' if used at the beginning or in the middle of a Persian word. So, here the character set is designed to include the variations of these alphabet also alongwith 10 numerals and 9 selected symbols. Also certain Persian characters have dots (similar to 'i' in English) either below or above the main body of the character.
855
This is where the DP and CO in the display module come handy. Since Persian text is written from right to left, the displayed characters are in a much more readable form if the DP and the CO lie on the right half of the display module. Therefore the modules that contain them on the left half (eg. HDSP-6300) can be mounted upside down. Fig. 2 shows the 16-segment display module used alongwith its element identification. It is to be noted here that: a) the symbol can be used to represent both a 'full stop' and a 'zero', b) the resulting display ' 1 I and for the alphabet I I I and I > are also used for representing digit '1' and 'greater than' signs respectively, c) the symbol is used to represent a decimal point in Persian, d) 'colon' ( : ) can be used to represent a division sign, e) some Persian characters have got three dots, e,.g. '5', but they are also written as ' 5 ' . It is the latter form in which
Fig. 1 Block schematic for displaying Persian characters using 18-element display modules.
IEEE Transactions on Consumer Electronics, Vol. 35, No. 4, NOVEMBER 1989
dl
d2
manufactured. It is to be further noted that the suggested layouts can also be used for CRT implementation, details of which
C
b
/ a2
a1 Fig. 2 Alphanumeric display module alongwith its segment identification.
d5dr +
d3d2d Id1
00
01 __
10
11
Is.
0000 000 1 00 10
these characters appear in the display, f) the character I I (equivalent to the sound 'A' in English) takes the form ' L ' at the end of a word, and g) 'semi-colon' is not necessary in Persian script.
0011 0 100 0101 0110 0111
These minor details have been taken into account while designing the 64-character ASCII set presented in the fig. 3 . The layouts have been specially designed keeping in mind the fact that Persian script requires that the letters are to be joined, where appropriate, to form a word. For this reason it would be more fitting to choose those display chips where the separation between two successive characters is smaller. The above scheme can be easily realized on commercially avai1able 16-segment LED/ LCD display modules as nothing new is to be designed or
1000 100 1 I010 1011 1100 1101 1110 1111
* character ** display Fig. 3 Resultant displays for Persian alphanumeric characters.
Nia and Beg:
Alphanumeric Persian Characters Using Standard 16-Segment Displays
has already been given for a different language earlier [l]. The X- and Y- deflection waveforms have to be suitably designed. CONCLUSIONS
A scheme has been presented to make possible the use of commercially available 16segment alphanumeric display modules to display contemporary Persian alphabet and numerals alongwith some selected symbols. A 64-word ASCII character set plus other realization details have been given. REFERENCES [l] M.S. Beg and W. Ahmad, 'A New Bar Matrix Alphanumeric CRT Display For Arabic', IEEE Trans. Consumer Electronics, Nov. 1987, Vol. CE-33, pp.594-598. [2] K.T. Lau, 'Segmented Chinese Numeric Display', IEEE Trans. Consumer Electronics, Nov. 1987, Vol. CE-33, pp.599-602. [3] M.S. Beg, 'A Novel Bar Matrix Display For Greek And English Alphanumeric Characters', IEEE Trans. Consumer Electronics, Nov. 1988, Vol. CE-34, pp. 933-936.
[4] W.L. Goh and K.T. Lau, 'A Microprocessor-Based Dot Matrix Display System For Japanese Hiragama Syllables', IEEE trans. Consumer Electronics, Feb. 1989, Vol. CE-35, pp. 32-36. [5] M.S. Beg and W. Ahmad, 'Dot Matrix Alphanumeric Display System For Arabic', IEEE Trans. Consumer Electronics, Feb. 1987, V O ~CE-33, pp. 47-50.
851
[6] Optoelectronic Designers Catalog, Hewlett-Packard, 198889.
F. Farzin-Nia was born in Mashad , Iran He in 1961. received his MSc. in Digital Communication Systems in 1986 from Louqhborouqh University of Tech: (LUT). Between 1986 and 1988 he was involved in research into ISDN in the Deptt. Electronic and Electrical Engg., LUT. Since becoming a research associate in 1989 in the same Deptt., he has been researching into optoelectronics. His main areas of interest are Digital Electronics, Optoelectronics, Digital Communications and Computer Networks. M.S. Beg got his B.Sc. Engg. in 1982 and M.E. in 1984. From 1984 to 1987 he was a lecturer at the Deptt. Electrical Engg., A.M.U. Aligarh. He is presently a Commonwealth scholar of research at the Deptt. Electronic and Electrical Engg., Loughborough University of Tech., Loughborough, U.K. His areas of academic interest are Digital Electronics, Digital Communication and Satellite Communication.
-
