Table 6: Uploading the File to the Module
Host sends Module sends
0xfe
’$’ (command))
’2’ (reference
’2’ (echo reference)
0x01 (host confirms echo)
0x5e (low size)
0x5e (echo)
0x01 (host confirms echo)
0x00 (high size)
0x00 (echo)
0x01 (file fits)*
0xFF (first byte of data)
0xFF (echo)
0x01 (host confirms echo)
0xFF (second byte of data)
0xFF (echo)
0x01 (host confirms echo)
0x20 (third byte of data)
0x20 (echo)
0x01 (host confirms echo)
etc
NOTE If the module detects that the file will not fit in the available memory when the file
size has been transmitted, it will send 0x08 instead of 0x01. In this case, the host should
cease transmission. The module will return to a ready state.
From this point, the module treats all data as raw and just stores it away. The module will store the data, then
read it back from memory and send the read value back to the host. If the host system receives an incorrect
echo, it should send status as 0x08 instead of 0x01. This will terminate the transfer. Upon termination, the
module will delete the partially completed file and return to a ready state.
6.4.3 A Sample Font File
Let’s look at a short sample font file containing only the letters "h", "i" and "http://www.hammondmfg.com/scpg.htmj".
First we need to define the font size. For this example we’ll use a 5x7 pixel font. Next, we have to draw the
bitmaps for each of the characters. We’ll use the examples shown in the Figure below.
Matrix Orbital GLK12232-25-WBL 21
Figure 9: Bitmaps for h, i, and j
Now the bitmaps have to be converted to bytes. If the font is 8 bits high, this is a pretty simple job
because each vertical column is simply one byte (lsb at the top). In this case however, the font is only 7 bits
high so the bytes "wrap around" as shown in the Figure below.
Figure 10: Bytes For a 7 Bit High Font
We’ve marked in the bits that are set for the letter "h". Remember that the bytes are ’inverted’, i.e., the
LSB is at the top. Each byte is shown in a different colour in the diagram. When the bytes are straightened
out, it’s simple enough to find their hex values, which are shown in the diagram above each byte. Trailing
zero bytes at the end of narrow characters are not included in the file.
Table 7: Example of a File Font
0xFF 0xFF 0X05 0x07 0x68 0x6A 0x00 0x0F
0x05 0x00 0x14 0x03 0x00 0x17 0x04 0x7F
0x04 0x81 0x80 0x07 0xC4 0x3E 0x10 0x02
0x20 0xB1 0x07
The colours refer to: Font information header, character ’h’, character ’i’, character ’j’.
Matrix Orbital GLK12232-25-WBL 22
Table 8: Explanation of Bytes in the File
FF FF placeholders for actual EOF
05 font width
07 font height
68 first ASCII character defined
70 last ASCII character defined
00 0F offset to definition of first character
(h)
05 number of bytes in definition of first
character
0014 offset to definitionof second charac-
ter (i)
03 number of bytes in definition of sec-
ond character
00 017 offset to definition of third character
(j)
04 number of bytes in definition of
third character
7F 04 81 80 07 definition of first character
C4 3E 10 definition of second character
02 20 B1 07 definition of third character
6.5 Working with Bitmap Files
Uploading a bitmap is the same as uploading a font file except that the character header information is
not required.
The bitmap file consists of a header followed by the bitmap data. The header format is as follows;
Placeholder for actual EOF (2 bytes, use 0xFF 0xFF - these bytes will be set to their final value by the
module)
x size of bitmap (1 byte)
y size of bitmap (1 byte)
Bitmap data follows with the bits organized vertically from the top left. The last byte may be padded with
zeros.
7 Miscellaneous Commands
7.1 General
The commands listed in this chapter don’t readily fit in any of the other categories, or are used in more
than one category.
Matrix Orbital GLK12232-25-WBL 23

GLK12232-25-WB-E

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