HD66765 Datasheet, PDF (41/71 Pages) Hitachi Semiconductor – 396-channel Segment Driver with Internal RAM for 4096-color Displays

HD66765
When high-speed RAM write mode is used, note the following.
Notes: 1. The logical and compare operations cannot be used.
2. Data is written to RAM each four words. When an address is set, the lower two bits in the
address must be set to the following values.
*When ID0=0, the lower two bits in the address must be set to 11 and be written to RAM.
*When ID0=1, the lower two bits in the address must be set to 00 and be written to RAM.
3. Data is written to RAM each four words. If less than four words of data is written to RAM, the
last data will not be written to RAM.
4. When the index register and RAM data write (R22h) have been selected, the data is always
written first. RAM cannot be written to and read from at the same time. HWM must be set to
n _{0 while RAM is being read.}
tio ^{5. High-speed and normal RAM write operations cannot be executed at the same time. The mode}
must be switched and the address must then be set.
a _{6. When high-speed RAM write is used with a window address-range specified, dummy write}
ific ^{operation may be required to suit the window address range-specification. Refer to the High-}
Speed RAM Write in the Window Address section.
ec _{Table 20 Comparison between Normal and High-Speed RAM Write Operations}
ry ^{Sp Logical operation function}
a _{Compare operation function}
in ^{Swap function}
Write mask function
lim ^{RAM address set}
Normal RAM Write
(HWM=0)
Can be used
Can be used
Can be used
Can be used
Can be specified by word
Pre ^{RAM read}
Can be read by word
High-Speed RAM Write
(HWM=1)
Cannot be used
Cannot be used
Can be used
Can be used
ID0 bit=0: Set the lower two bits to 11
ID0 bit=1: Set the lower two bits to 00
Cannot be used
RAM write
Can be written by word
Dummy write operations may have to be
inserted according to a window address-
range specification
Window address
Can be set by word
Can be set by word
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