Epson LQ-800 Defining Your Own Characters, The bits within each byte have values of 1, 2, 4, 8, 16, 32, 64, and, Data numbers, Figure 6-6. User-definedcharacter

Defining Your Own Characters

The first step in defining characters is to place the dots on a grid just as you want them to print. The examples here, like the ones in the graphics section, use an X to represent each dot. In Figure 6-6 you see a draft grid with a simple user-defined character planned on it.

Figure 6-6. User-defined character

Now you translate the dot pattern you’ve created on paper to a numeric format so you can send the information to the LQ. Every dot has an assigned value. Each vertical column (which has a maximum of 24 dots) is first divided into three groups of eight dots. Each group of eight dots is represented by one byte, which consists of eight bits. Hence, one bit represents each dot.

Data numbersThe bits within each byte have values of 1, 2, 4, 8, 16, 32, 64, and

128.In the vertical column of dots, the bits are arranged so that the most significant bit (which has a value of 128) is at the top and the least significant bit (which has a value of 1) is at the bottom.

Figure 6-7 shows how to use this method to calculate the data numbers for the example character. On the left side of the figure the data numbers are calculated for the middle column. The value of each byte is calculated by adding the values of the rows where dots appear. The right side of the figure shows the whole character with the three data numbers for each column indicated at the bottom.

6-13