hd66421 Renesas Electronics Corporation., hd66421 Datasheet - Page 23

• Manufacturer Part Number: hd66421
• Description: Ram-provided 160 Channel 4-level Grey Scale Driver For Dot Matrix Graphics Lcd
• Manufacturer: Renesas Electronics Corporation.

Display RAM Reading by LCD Controller:
Data is read by the HD66421 to be displayed
asynchronously with accesses by the MPU.
However, because simultaneous access could
damaging data in the display RAM, the HD66421
internally arbitrates access timing; access by the
Preliminary
H'00
H'01
H'63
H'7F
H'00
H'01
H'02
H'63
H'00
H'01
H'02
H'63
H'0
H'0
H'0
H'1
H'1
H'2
Figure 17 Display Address Increment
Invalid area
Valid area
WLS= 0
WLS= 0
WLS= 0
WLS= 0
WLS= 0
(b) INC = 1, MON= 0
(c) INC = 1, MON= 1
(a) INC = 0
H'27
H'27
H'26
23
MPU usually has priority and so access by the
HD66421 is placed between accesses by the MPU.
Accordingly, an appropriate time must be secured
(see the given electrical characteristics between
two accesses by the MPU).
H'28
H'28
H'28
Valid area (WLS= 1)
Invalid area
WLS= 1
WLS= 1
WLS= 1
WLS= 1
WLS= 1
H'35
H'35
H'34
Rev. 1.1E '99.02.10
HD66421