LM1236 National Semiconductor Corporation, LM1236 Datasheet - Page 29

• Manufacturer Part Number: LM1236
• Description: 150 Mhz I2c Compatible Rgb Preamplifier With Internal 254 Character Osd Rom, 512 Character Ram And 4 Dacs
• Manufacturer: National Semiconductor Corporation

ATT2C0n
ATT2C1n
ATT2C2n
ATT2C3n
ATT4C0n
ATT4C1n
ATT4C2n
ATT4C3n
ATT4C4n
ATT4C5n
ATT4C6n
ATT4C7n
LM1236 Address Map
TWO-COLOR ATTRIBUTE RAM
This address range (0x8440–0x8497) contains the attribute lookup tables used for displaying two-color characters. There are 16
groups of 4 bytes each according to the format shown in Table 13. The attributes are stored starting with Color 0 (background)
and each color is stored red first, green second and then blue. They may be written or read using the following address format:
When reading, it is OK to read only one, two, or all three bytes. When writing more than one 2-color attribute using the auto
increment feature, all four bytes must be written. When writing, bytes 0 through 2 must be written in order. Bytes 0 through 2 will
take effect after byte 2 is written. Since byte 3 contains all reserved bits, this byte may be written, but will have no effect. Any bits
marked as “X” are reserved and should be written to with zeros and should be ignored when the register is read.
FOUR-COLOR ATTRIBUTE RAM
This address range (0x8500–0x857F), contains the attribute lookup tables used for displaying four-color characters. There are 16
groups of 8 bytes each according to the format shown in Table 14. The attributes are stored starting with Color 0 (background)
and each color is stored red first, green second and then blue. They may be written or read using the following address format:
When writing, bytes 0 through 2 must be written in order and bytes 4 through 6 must be written in order. Bytes 0 through 2 will
take effect after byte 2 is written. Bytes 4 through 6 will take effect after byte 6 is written. Since bytes 5 and 7 contain all reserved
bits, these bytes may be written, but no effect will result. When reading, it is OK to read only one, two, or all three bytes. If writing
more than one 4-color attributes using the auto increment feature, all eight bytes must be written. Any bits marked as “X” are
reserved and should be written to with zeros and should be ignored when the register is read.
Register
Register
0x8440 + 4n
8500 + (n*8)
Address
Address
+1
+2
+3
+1
+2
+3
+4
+5
+6
+7
TABLE 14. LM1236 Four-Color Attribute Registers
TABLE 13. LM1236 Two-Color Attribute Registers
where: N = Attribute number (0x0 ≤ N ≤ 0xF)
where: N = Attribute number (0x0 ≤ N ≤ 0xF)
(Continued)
B = Attribute byte number (0x0 ≤ B ≤ 0x3)
B = Attribute byte number (0x0 ≤ B ≤ 0x7)
Address = 0x8440 + (N
Address = 0x8500 + (N
C1B[0]
C1B[0]
C3B[0]
D7
D7
X
X
X
X
X
X
C0B[1:0]
C0B[1:0]
C2B[1:0]
D6
D6
X
X
X
X
X
X
29
C1G[2:0]
C1G[2:0]
C3G[2:0]
D5
D5
*
*
X
X
X
X
0x4) + B
0x8) + B
C0G[2:0]
C0G[2:0]
C2G[2:0]
D4
D4
X
X
X
X
EF[3:0]
EF[3:0]
D3
D3
X
X
X
X
C1R[2:0]
C1R[2:0]
C3R[2:0]
D2
D2
X
X
X
X
C0R[2:0]
C0R[2:0]
C2R[2:0]
D1
D1
X
X
X
C1B[2:1]
C1B[2:1]
C3B[2:1]
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C0B[2]
C0B[2]
C2B[2]
D0
D0
X
X
X