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参数资料
| 型号： | LM1247AAG/NA/NOPB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 音频／视频放大 |
| 英文描述： | 3 CHANNEL, VIDEO PREAMPLIFIER, PDIP24 |
| 封装： | PLASTIC, DIP-24 |
| 文件页数： | 17/48页 |
| 文件大小： | 3141K |
| 代理商： | LM1247AAG/NA/NOPB |
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LM1247 Address Map (Continued)
TABLE 9. Page RAM Format
ATTRIBUTE CODE
CHARACTER CODE
BANK SEL.
BANK CHARACTER
ATT[3:0]
CC[7:6]
CC[5:0]
Bits 7-6 determine which Bank Select Register is used to look up the 3 bit address of the bank where the character will be called
from. Bits 5-0 determine which of the 64 characters is called from that bank. Bits 11-8 address one of the 16 attributes in the table
containing the colors and enhanced features to be used for this particular character. Two separate attribute tables are used, one
for 2-color characters, the other for 4-color characters. Note there are 16 available attributes for 2-color characters and a different
set of 16 available attributes for 4-color characters. It is the bank number in the register called by the Bank Select bits, which
determines whether the character has a 2-color or 4-color attribute.
ATTRIBUTE CODE
The attribute code to be used for subsequent characters is written just as a character code or control code, but is stored with each
of the characters which are subsequently written to the Page RAM until the write operation ends. The attribute code is identified
as the first byte sent in a write operation. This attribute code addresses one of 16 locations in the attribute table, and is shown
in Table 10. This code is used for all following characters until a new attribute code is written with a new write operation.
TABLE 10. Attribute Code
ATTRIBUTE CODE
X
ATT[3:0]
Bits 7-4 of this byte are reserved and should be written as zeros. Bits 3-0 are stored in bits 11:8 of the Page RAM, along with its
corresponding character codes and selects one of the 16 entries in the attribute table (described later).
END-OF-LINE CODE
To signify the end of a line of characters, a special End-of-Line (EOL) code is used in place of a character code. This code, shown
in Table 11 tells the OSD generator that the character and attribute codes which follow must be placed on a new line in the
displayed window. Bits 7-1 are zeros, bit 0 is a one. The attribute which is stored in Page RAM along with this code is not used.
TABLE 11. End-of-Line Code
ATTRIBUTE CODE
END-OF-LINE CODE
ATT[3:0]
0000000
1
SKIP-LINE CODE
In order to allow finer control of the vertical spacing of character lines, each displayed line of characters may have up to 15
skipped (i.e., blank) lines between it and the line beneath it. Each skipped line is treated as a single character pixel line, so
multiple scan lines may actually be displayed in order to maintain accurate size relative to the character cell. An internal algorithm
maintains vertical height proportionality (see the section on Constant Character Height Mechanism). To specify the number of
skipped lines, the first character in each new line of characters is interpreted differently than the others in the line. Its data are
interpreted as shown in Table 12, with the attribute bits setting the color of the skipped lines.
TABLE 12. Skipped-Line Code
ATTRIBUTE CODE
NUMBER OF SKIPPED LINES
ATT[3:0]
XXXX
SL[3:0]
Bits 7-4 are reserved and should be set to zero. Bits 3-0 determine how many blank pixel lines will be inserted between the
present line of display characters and the next. A range of 0-15 may be selected. Bits 11-8 determine which attribute the pixels
in the skipped lines will have, which is always called from the two-color attribute table. The pixels will have the background color
(Color 0) of the selected attribute table entry.
Note that the pixels in the first line immediately below the character may be overwritten by the pixel override system that creates
the button box. (Refer to the Button Box Formation Section for more information).
After the first line, each new line always starts with an SL code, even if the number of skipped lines to follow is zero. This means
an SL code must always follow an EOL code. An EOL code may follow an SL code if several “transparent” lines are required
between sections of the window. See example 3 below for a case where skipped lines of zero characters are displayed, resulting
in one window being displayed in two segments.
LM1247
www.national.com
24
相关PDF资料 |
PDF描述 |
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| LM1253AAE/NA | ON-SCREEN DISPLAY IC, PDIP28 |
| LM1267NA/NOPB | 3 CHANNEL, VIDEO PREAMPLIFIER, PDIP24 |
| LM1269NA/NOPB | 3 CHANNEL, VIDEO PREAMPLIFIER, PDIP24 |
| LM1276AAA/NA | 1 CHANNEL, VIDEO PREAMPLIFIER, PDIP28 |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LM1247DMC/NA | 制造商:Texas Instruments 功能描述: |
| LM124A | 制造商:NSC 制造商全称:National Semiconductor 功能描述:Low Power Quad Operational Amplifiers |
| LM124AD | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:LOW POWER QUAD OPERATIONAL AMPLIFIERS |
| LM124ADR | 制造商:TI 制造商全称:Texas Instruments 功能描述:QUADRUPLE OPERATIONAL AMPLIFIERS |
| LM124ADT | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Voltage-Feedback Operational Amplifier |
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