LM1247 National Semiconductor, LM1247 Datasheet - Page 29

• Manufacturer Part Number: LM1247
• Description: 150 MHz I2C Compatible RGB Preamplifier with Internal 512 Character OSD ROM, 512 Character RAM and 4 DACs
• Manufacturer: National Semiconductor

Building Display Pages
EXAMPLE 2
A 3x2 character matrix of characters on a black background is to be displayed on the screen using 2-color character codes. Two
gray skip lines are desired below the first line of characters, and 3 gray skip lines are desired below the second line. This is shown
in Figure 26.
The first line of characters will use attribute 0, the second line will use attribute 0 for the first character, attribute 1 for the second
character, and attribute 2 for the third character. The skip lines will use attribute 3, which we choose to be the inverse of attribute
1.
Notes:
• The character codes for “A”, “B”, etc. are from bank 4 of the sample font shown in Figure 29 through Figure 36.
• For this example, we assume bank 4 is selected by Bank Select Register 3, so the two upper bits of the character codes are
• Every line begins with an AC and an SL code. The first location addressed by the Window 1 Start Address register must always
• If an I
• Every line except the last line of a display window ends with an EOL code. The character immediately after an EOL is always
• The last character in a display window is an EOS code. The EOS must NOT follow an EOL character.
• Table 19 shows the data sent to the LM1247 for the entire image, in 7 transmissions.
both 1’s. Therefore, the code stored in page RAM for the “A” will be 0xC2.
contain the SL for the first line of display window # 1.
AC.
the SL value for the next line, unless the window contains just one line.
Data Sent
Data Sent
0xBA
0x04
0x01
0x00
0x05
0x06
0x07
0x00
0x40
0x84
2
C transmission finishes without an EOL code (in the middle of a line) the first byte sent in the next transmission is an
Character “C”
End-of-Line (EOL) code
Skip 0 lines
Character “D”
Character “E”
Character “F”
End-of-Screen (EOS) code
I
I
LM1247 Slave Write Address
Two-color attribute location 0 address LSB
Two-color attribute location 0 address MSB
2
2
C stop condition
C start condition
TABLE 18. Example 1 Data Transmissions (Continued)
TABLE 19. Example 2 Data Transmissions
(Continued)
FIGURE 26. Example 2 OSD
Description
Description
29
20048441
RAM Address
RAM Address
8003
8004
8005
8006
8007
8008
8009
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