HD66421 Datasheet, PDF (18/46 Pages) Hitachi Semiconductor – (RAM-Provided 160 Channel 4-Level Grey Scale Driver for Dot Matrix Graphics LCD)

Preliminary
Rev. 1.1E '99.02.10
HD66421
Word Length
The HD66421 can handle either 8- or 6-bits as a
word. In the display memory, one X address is
assigned to each word of 8- or 6-bits long in X
direction.
When the 6-bits mode is selected, only data on
DB5 to DB0 are used and data on DB7 and
DB6 are discarded. This word length is only
applied to data to internal RAM. The word
length of internal register is always 8-bits
SEG1
H'00
H'01
8 bits
LCD drive signal output
SEG160 SEG1
H'00
H'01
6 bits
LCD drive signal output
SEG160
H'62
H'63
H'0
MSB
H'1
X addresses
H'62
H'63
H'27
H'0 H'1
MSB
H'34 H'35
X addresses
(a) Address assignment when one
word is 8 bits long (MON=0)
(b) Address assignment when one
word is 6 bits long (MON=0)
Figure 11 Display RAM Addresses in Gray Scale Mode
H'0
Y0 _{1 1 1 0 0 1}
Y1 0 0 0 1 1 0
D D D D D D ^{Display RAM}
BBBBBB
543210
H'35
100
011
DDD
BBB
054
H'35
Y0 _{1 1 1 0 0 1}
Y1 0 0 0 1 1 0
D D D D D D ^{Display RAM}
BBBBBB
103254
H'0
100
011
DDD
BBB
410
(a) WLS= 1, ADC = 0, MON= 0
H'35's bit7,6, and 3 to 0 are disable .
(b) WLS= 1, ADC = 1 MON= 0
H'0's bit7 to 2 are disable.
H'0
Y0 _{1 1 1 0 0 1}
Y1 0 0 0 1 1 0
D D D D D D ^{Display RAM}
BBBBBB
543210
H'34
00 100
11 011
DDDDD
BBBBB
05432
H'34
Y0 _{1 1 1 0 0 1}
Y1 0 0 0 1 1 0
D D D D D D ^{Display RAM}
BBBBBB
012345
H'0
00 100
11 011
DDDDD
BBBBB
50123
(c) WLS= 1, ADC = 0, MON= 1
H'34's bit7,6, and 1,0 are disable .
(d) WLS= 1, ADC = 1, MON= 1
H'0's bit7 to 4 are disable.
Figure 12 Display RAM Bits Map at 6-bits Mode
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