Star Micronics NX-10 user manual Calculating nl and n2 Kf the numb

largest number we can send in one byte (that’s what the BASIC CHR$( ) function sends: one byte) is 255. And with the normal density graphics it’s possible to have a graphics image as wide as 480 dots. So to figure out how many columns of graphics data to expect, your printer multiplies n2 by 256 and adds the value of nl to the product. If you divide the number of columns by 256, then n2 is the quotient and nl is the remainder (why not let your computer figure it out for you: if the number of columns is

assigned to variable X, then nl =X MOD 256 and

nZ=INT(X/256)). Table 7-l might make things even easier.

Table 7-1

Calculating nl and n2.

kf the numb

1024		to	1279	1	x-1024
I	ILO”	L” IJ3.J		I	x-1280
t	1536	to	1791	I	x-15	?G
						V”	I
	innn	L-	1920	1	x-1792

4

5 G

;

nSpecifying the graphics data

Now that we’ve told the printer how much data to expect, we better figure out how to send that information! Just as you do with download characters, with dot graphics you have control over the firing of every single pin on the print head. In Figure 7- 1, you can see that we’ve. labelled each pin on the print head with a number, as we did with download characters. And speci- fying pins to fire is done in the same way: to fire the second pin from the top, for instance, send a CHR$(64). Firing several pins at once is done in a similar fashion. For example, to print the first, third, and fourth dots, add their values (128 + 32 + 16) to send this total: CHR$(176). This is one byte of graphics data; it would replace ml in our format statement.