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| en:examples:display:lcd_alphanumeric [2010/03/10 18:25] – Helen | en:examples:display:lcd_alphanumeric [2020/07/20 09:00] (current) – external edit 127.0.0.1 |
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| ====== Alphanumeric LCD ====== | ====== Alphanumeric LCD ====== |
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| //Necessary knowledge: [HW] [[en:hardware:homelab:lcd]], [LIB] [[en:software:homelab:library:module:lcd_alphanumeric]], [LIB] [[en:software:homelab:library:delay]], [PRT] [[en:examples:timer:periodic_interrupt]]// | //Necessary knowledge: [LIB] [[en:software:homelab:library:module:lcd_alphanumeric]], [LIB] [[en:software:homelab:library:delay]], [PRT] [[en:examples:timer:periodic_interrupt]]// |
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| ===== Theory ===== | ===== Theory ===== |
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| [{{ :examples:display:lcd_alphanumeric:lcd_alphanumeric_abc.png?200|The text formed of alphanumerical LCD pixels' matixes.}}] | [{{ :examples:display:lcd_alphanumeric:lcd_alphanumeric_abc.png?200|The text formed of alphanumerical LCD pixels' matrixes.}}] |
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| Besides the screen Alphanumerical LCD has also controller which controls the segments of the screen according to the commands from the communication interface. A controller has a preprogrammed card of letters, where each letter, number or symbol has its own index. Displaying the text on the screen is basically done by sending the indexes to the controller. In reality there must be more control orders sent to the controller before anything can be displayed. It is important to get familiarize with each LCD data-sheet, because there are many different types of LCDs and they all are controlled differently. | Besides the screen Alphanumerical LCD has also controller which controls the segments of the screen according to the commands from the communication interface. A controller has a preprogrammed card of letters, where each letter, number or symbol has its own index. Displaying the text on the screen is basically done by sending the indexes to the controller. In reality there must be more control orders sent to the controller before anything can be displayed. It is important to get familiarize with each LCD data-sheet, because there are many different types of LCDs and they all are controlled differently. |
| ===== Practice ===== | ===== Practice ===== |
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| Home Labs digital module connects a 2x16 symbol alphanumerical LCD WC 1602A. For controlling the screen, there is a 4-bit data-bus and 3 control pins, but its communication protocol is too capacious, to be explained here. For simplicity, the library of the Home Lab has corresponding functions for using the display. | HomeLabs Digital i/o module connects a 2x16 symbol alphanumerical LCD WC 1602A. For controlling the screen, there is a 4-bit data-bus and 3 control pins, but its communication protocol is too capacious, to be explained here. For simplicity, the library of the HomeLab has corresponding functions for using the display. |
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| Before using the display it is vital to adjust its settings. For this purpose is the // lcd_alpha_init// function, which sets a blinking cursor on the screen. On screen is always only one active position for the cursor where next letter is entered, regardless whether it can be seen or not. So before entering the text, the cursor must be taken to the desired place. For changing the position of the cursor is a function lcd_alpha_goto_xy and for displaying it lcd_alpha_write_string. All the functions of the alphanumerical LCD are explained in its library. | Before using the display it is vital to adjust its settings. For this purpose is the // lcd_alpha_init// function, which sets a blinking cursor on the screen. On screen is always only one active position for the cursor where next letter is entered, regardless whether it can be seen or not. So before entering the text, the cursor must be taken to the desired place. For changing the position of the cursor is a function lcd_alpha_goto_xy and for displaying it lcd_alpha_write_string. All the functions of the alphanumerical LCD are explained in its library. |
| <code c> | <code c> |
| // | // |
| // The example of using the alphanumerical LCD of the Home Lab. | // The example of using the alphanumerical LCD of the HomeLab. |
| // The clock time starting at the beginning of the program is displayed on the LCD. | // The clock time starting at the beginning of the program is displayed on the LCD. |
| // | // |
| seconds % 60); | seconds % 60); |
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| // Displaying the clock text in the beginning of the second row of the LCD. | // Displaying the clock text in the LCD. |
| lcd_alpha_goto_xy(0, 1); | lcd_alpha_goto_xy(0, 1); |
| lcd_alpha_write_string(text); | lcd_alpha_write_string(text); |
