The Design of a Complete Segmented Display Unit for Arabic Alphanumeric Characters

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1 The Design of a Complete Segmented Display Unit for Arabic Alphanumeric Characters MOHAMMAD OSIUR RAHMAN 1, MUBASHSHARUL ISLAM SHAFIQUE 2, EDGAR SCAVINO 3, HASSAN BASRI 3 1 Department of Computer Science and Engineering University of Chittagong, Chittagong-4331 BANGLADESH 2 Jodrey School of Computer Science Acadia University, NS, B4P 2R6 CANADA 3 Faculty of Engineering Universiti Kebangsaan Malaysia MALAYSIA Abstract: - There are four forms for most of the Arabic characters- initial, medial, final and isolated. This paper presents the design of a complete display unit for Arabic alphanumeric characters. The word complete signifies that the proposed display unit can represent all forms of entire Arabic alphabets as well as Arabic numerals. The first segmented display unit for Arabic characters in the world covered only the isolated form and did not follow any base line to display a sequence of characters. This work extends the capability to represent all the forms of Arabic characters and follows a base line to represent a sequence of characters. Here a grid structure of 25 non-overlapping segments has been discovered. There can be 109 alphanumeric characters (at least 99 characters such as isolated form- 30, final form-29, medial form- 21, initial form- 20; and 10 numerals) to be displayed and 7-bit input is used to represent each character. After analyzing appropriate segments to be activated for every character, respective logic functions of all segments have been derived to display the entire set of Arabic alphanumeric characters. Key-Words: - Display Unit, Dot Matrices, Karnaugh map, LED (Light Emitting Diode), 7-Segment display. 1 Introduction Segmented representation is used in lieu of the dot matrices representation for alphanumeric characters of different languages. Due to concerns of cost, power loss and design complexity, the segmented representation becomes more popular over the dot matrices. There are many display units for English and Bangla alphanumeric characters. There are three common formats of LED displays for English. For displaying only numerals and hexadecimal letters, simple 7-segment displays [1, 2] are used. To display numbers and the entire alphabetic, 18- segments display [1, 2] or 5 7 dot-matrix displays [1, 2] can be used. 26-segment [3], and 31-segment [4, 5] models are proposed for Bengali Alphabetic characters, Bengali characters, and Bengali composite letters respectively. For Arabic, there are three segmented display units only for numerals shown in [6, 7] and the first 18-segment display unit only for the initial form of Arabic characters is proposed in [8]. No complete segmented display has been developed so far for Arabic alphanumeric characters. At present, Arabic alphabetic characters are represented by using dot matrices, so the cost of the display unit increases due to the storage space, the large number of dots, the power loss and design complexity [3-8]. In this proposed segmented display system only 25 segments are used, which saves considerable amount of storage space and production costs. 2 Design Philosophy of the Proposed Arabic Display Unit There are 30 characters (including Lam-Alif) and 10 numerals in Arabic language. Writing in Arabic is unicase, i.e., it does not have the concepts of upper and lower case letters but the shape of these letters change as a function of their usage. Based on the context, a basic character can have up to four different forms: initial, medial, final and isolated [9]. Motivation for the proposed 25-segment display unit came from the 18-segment display proposed by Rahman et al. [8], which is shown in Fig.1(a). But this grid ISBN: ISSN:

structure supports only the isolated form of the Arabic characters and numerals. Hence, it cannot be used to display initial, medial or final forms of the Arabic characters.

2 structure supports only the isolated form of the Arabic characters and numerals. Hence, it cannot be used to display initial, medial or final forms of the Arabic characters. Besides, it lacks a common base line for all characters. As a result, it creates vertical displacement between successive characters if we try to display a sequence of isolated characters. After modification to the previous 18-segment grid structure, we propose a new grid structure consisting of 25 segments shown in Figure 1(b). For simplicity reasons, each of the 25 segments is referred to by means of a letter of the Roman alphabet. Every form of all Arabic characters and numerals can be displayed by using this new grid structure. Characters generated from this display unit strictly maintain common base line. So, using this unit we can construct Arabic words, which so far was impossible by the previous 18-segment display. There can be 109 distinct alphanumeric character shapes (10 numerals and at least 99 character shapes such as isolated form- 30, final form-29, medial form- 21, initial form- 20) to be displayed and so 7-bit input is used to run the driving circuit. Individual pattern of this input corresponds to a unique character form and activates necessary segment(s) for displaying it (Fig.2). After analyzing which segments will be activated for which character, appropriate logic function for each segment has been derived in order to represent each Arabic alphanumeric character. 3 Methodology of Characterization for Arabic Characters Display quality, power consumption, cost of design complexity, memory usage and applicability are the most decisive factors for designing any display unit [10]. Display quality of the alphanumeric characters means basic shape and beauty of the individual character, which is the main concern for any display unit because low display quality leads to damages and user rejection. At the same time, the number of segments has direct impact on power consumption and cost of memory and design complexity. Thus to design this display unit, we have used minimum number of segments while ensuring the unique shape and beauty of all 109 characters. As writing in Arabic is cursive, we have used four different techniques for four forms of Arabic characters. For the isolated form, it has been observed that some characters can be represented in various ways by using different combinations of segments. We used a minimum number of segments that can provide the quality display for the characters. Here the gap between neighbor characters needs not to be considered. For example, to represent the isolated form of Lam,(ل) we used {a,d,o,s} in lieu of {b,g,k,q,r}. (a) (b) Figure 1. (a)the Model of 18 segments for Arabic Alphabetic Characters, (b)the Model of 25 segments for Complete Arabic Alphanumeric Characters In the case of initial forms, there are two major aspects for consideration display quality and the gap between the target initial character and its left neighbor character. If we want to provide a quality appearance for a sequence of characters, we have to reduce the gap between the target character and its left neighbor character. So, to represent the an initial character, we took the segments from the left side of the grid structure as far as possible and try to extend the character by taking maximum number of segments from left side of the base line for reducing the gap with its left neighbor. Such as for initial form of Ain,(ع) {e,k,q} is chosen instead of {i,g,k,l,q}. ISBN: ISSN:

3 For the medial form, three major issues are addresseddisplay quality and two gaps between the target character and both left and right neighbors. So, to represent the target character we choose minimum number of segments and try to extend the character by taking maximum number of segments from both left and right side of the base line for reducing the gap with its left and right neighbor characters. Such as in lieu of {g,k,l,y}, {g,k,l,m,q,y} is used to represent the.(ب) medial form of Ba 7-bit input (A,B,C,D, E,F,G) Driving Circuit 25 segments (a,b,..x,y) Figure 2. Overall block diagram of the complete Arabic display driver system. For the final form, we considered two major issues display quality and the gap between the target character and its right neighbor. To represent the target character we choose the segments from the right side of the grid structure as far as possible and try to extend the character by taking maximum numbers of segments from right side of the base line in order to reduce the gap between the target character and its right neighbor. Such as to display the final form of Alif,(ا) {b,g,l,m } is chosen in lieu of {a,d,k,l,m}. 4 Characterization of Arabic Alphanumeric Characters by Using the Proposed Segmented Display Unit All Arabic alphanumeric characters along with their four forms can be represented by using different combinations of non-overlapping 25 segments: a, b, c, d, e, f, g, h, i, j, k,l, m, n, o, p q, r, s, t, u, v, w, x, and y. The structure of non-overlapping segments is already shown in Fig.1(b). Table 1 presents partial Arabic alphanumeric characters as a sample generated by using this display unit. We get the truth table for Arabic alphanumeric characters from Table 1, which is shown in Table 2. In Table 2, each index value corresponds to decimal equivalent of respective 7-bit input pattern, which also precedes every character in Table 1. The truth table yields us Boolean function for each of the 25 segments. K-map minimization software [11] is used to minimize them. The minimized Boolean functions are shown in Table 4. To list all Arabic alphanumeric characters in their four forms, we use the following notation: Character Name, Basic Symbol {(segments used to represent isolated form), (segments used to represent final form), (segments used to represent medial form), (segments used to represent initial form)} If any particular form is absent for a character, NULL is used instead of segment list. For example, by using the above notation four forms of Ghain (غ) are listed as follows: Ghain, غ {(e,k,n,t,v),(e,g,k,l,m,n,t,v), (h,i,j,k,l,m,q,w), (e,k,q,u)} Here, the isolated form of Ghain (غ) is represented by e, k, n, t, and v segments; the final form of Ghain (غ) is represented by e, g, k, l, m, n, t, and v segments; the medial form of Ghain (غ) is represented by h, i, j, k, l, m, q, and w segments; the initial form of Ghain (غ) is represented by e, k, q, and u segments. In this way, all Arabic alphanumeric characters are represented. Some characters are shown in Table 3 as samples. Some minimized Boolean functions for segments out of 25 are shown in Table 4 as sample. 6 Conclusions The paper emphasized on a successful display of four forms of Arabic alphanumeric characters through proposed 25-segment display unit. The strength of this design is that it is capable of writing consecutive characters to form Arabic strings. The display structure is designed without any intersection of the constituent segments. Moreover it follows the same base line for all characters, which is a must to write Arabic words. From now onwards, the proposed design may be used rather than dot matrices to represent Arabic alphanumeric characters, which is more efficient, cost effective and consumes less storage. In future, attempts will be made to include the display of punctuation and special characters of Arabic Language and Urdu alphanumeric characters along with the present system. ISBN: ISSN:

4 Table 1. Representation of Arabic Alphanumeric Characters by Using Proposed 25-Segment Display Unit Serial Letter Name Isolated Form Final Form Medial Form Initial Form Number 1 Alif 2 Tha / Sa 3 Kha 4 Zai / Za 5 Sheen 6 Dad / Dwad 7 Zhoa 8 Ghain 9 Fa 10 Kaf 11 Ya ISBN: ISSN:

5 Table 2. Table for Arabic Alphanumeric Characters Using 25-segments Display Index Shape a No b c d e f g h i j k l m n o p q r s t u v w x y ISBN: ISSN:

6 Table 3. Arabic alphanumeric characters in their References: four forms [1] Cook B.M. and White N.H., Computer Serial Structural components of Four Forms of Peripherals, 3 rd Edition, United Kingdom, pp. No. Arabic Alphanumeric Characters 43-45, Alif, ا {(a,d), (b,g,l,m), (NULL),(NULL)} [2] Hall D.V., Microprocessor and Interfacing: 2. Tha/Sa,ث{(j,k,l,q,r,u,v,w),(j,k,l,m,q,r,u,v,w), Programming and Hardware, 2 nd Edition, Tata (g,k,l,m,q,u,v,w),(g,k,q,u,v,w)} McGraw-Hill Publishing Co. Ltd., New Delhi, 3. Kha, خ {(k,n,p,t,u), (k,l,m,n,p,t,u), 2003, pp. 4, 267. (f,h,k,l,m,q,v), (f,h,k,l,q,v)} [3] Rahman M.O., and Kabir S.M.L., Designing 4. Zai/Za, ز {(g,n,v), (g,l,m,n,v), (NULL), (NULL)} 26-Segments Display for Bangla Characters, 5. Sheen,ش{(d,g,j,k,l,o,s,u,v,w),(d,g,j,k,l,m,o,s,u, Asian Journal of Information Technology, v,w), (d,g,j,k,l,m,q,u,v,w), (d,g,j,k,l,q,u,v,w)} Vol.3 No.8, pp , Dad/Dwad,ض{(d,e,i,j,k,l,o,s,v),(d,e,i,j,k,l,m,o, [4] Mahmud S., Arefin A.S. and Khan M.I., A s,v), (d,e,i,j,k,l,m,q,v), (d,e,i,j,k,l,q,v)} New Approach for Displaying All Bengali 7. Zhoa, ظ {(a,d,e,i,j,k,l,q,v), (a,d,e,i,j,k,l,m,q,v), Characters, Asian Journal of Information (NULL), (NULL)} Technology, vol.4 No.2, pp , Ghain, غ {(e,k,n,t,v),(e,g,k,l,m,n,t,v), [ 5] Chowdhury M.S., A Segmented Display (h,i,j,k,l,m,q,w), (e,k,q,u)} system for Bengali Composite Letters, The 9. Fa, ف {(e,g,k,n,s,u), (e,g,k,l,m,n,s,u), Chittagong University Journal of Science, vol. (e,g,k,l,m,q,u), (e,g,k,q,u)} 29(2), pp , Kaf, ك {(a,d,o,p,q,r,s), (a,d,k,l,m,o,p,q,r,s), [6] Rahman M.O., Azim M.A., Chowdhury (c,i,j,k,l,m,q), (c,i,j,k,l,q)} M.S., Islam M.N., Different Segment 11. Ya, ي {(e,k,n,s,x,y), (f,h,k,m,n,s,x,y), displays for Bangla, English and Arabic digits, in Proceedings of the 6 Dhaka, pp , [7] A.K.M. Khaled Ahsan Talukder and Kaushik Roy, Development of 16- Table 4. Simplified Boolean Functions For segment Multilingual Display Driver, in Segments Name of Proceedings of ICEECE, Dhaka, pp.27-31, Segments Simplified Boolean Functions [8] Rahman M.O., Billah M.M., and a = (A B C D G F E + A B CG FE + a Chowdhury M.C., Designing Display Unit A BC G FE + A BCGF E + ABC GF E + AB CGF E ); for Arabic Alphabetic Characters, in b = (A B C DG F E + A BCD GF E + Proceedings of M²USIC, Malaysia, TS3Ab ABC GF ); 5, pp.17-20, [9] Available at: c c = (A BCD GF E + AB C GF E ); d = (A B C D G F E + AB C DFE + hy.html d A BCGF E + ABC GF E + AB CGF E + [10]Rahman M.O. and Ahmed S., Comparative A B G FE + A BC G F + A BC FE + Study on Different Proposed Segmented A BD FE + CG FE + AG FE ); Display Units for Bangla Numerals, Asian v v = (ABC G F E + AB CG F E + Journal of Information Technology, vol. 4, No. AB C G F E + AB CG FE + A B CGF E 1, pp , B C G FE + A C G FE + BCG FE + [11] Karnaugh Map Minimizer v0.4, Available: A BC GF ); W w = (ABC D G E + A BCG E + ABC G F + AB G F E + AB C G E ); X y x = (ABCDGF E + A B CG F E + ABCG F E + A B C GFE + A B D GFE ); y= (ABCDGF E + A B C G F E + A BC G F E + A B GFE ); ISBN: ISSN:

Digital Logic (2) Boolean Algebra

Digital Logic (2) Boolean Algebra Boolean algebra is the mathematics of digital systems. It was developed in 1850 s by George Boole. We will use Boolean algebra to minimize logic expressions. Karnaugh