hd66765 Renesas Electronics Corporation., hd66765 Datasheet - Page 41

• Manufacturer Part Number: hd66765
• Description: 396-channel Segment Driver With Internal Ram For 4096-color Displays - Hitachi Semiconductor
• Manufacturer: Renesas Electronics Corporation.

When high-speed RAM write mode is used, note the following.
Notes: 1. The logical and compare operations cannot be used.
Table 20
Logical operation function
Compare operation function
Swap function
Write mask function
RAM address set
RAM read
RAM write
Window address
2. Data is written to RAM each four words. When an address is set, the lower two bits in the
3. Data is written to RAM each four words. If less than four words of data is written to RAM, the
4. When the index register and RAM data write (R22h) have been selected, the data is always
5. High-speed and normal RAM write operations cannot be executed at the same time. The mode
6. When high-speed RAM write is used with a window address-range specified, dummy write
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.
last data will not be written to RAM.
written first. RAM cannot be written to and read from at the same time. HWM must be set to
0 while RAM is being read.
must be switched and the address must then be set.
operation may be required to suit the window address range-specification. Refer to the High-
Speed RAM Write in the Window Address section.
Comparison between Normal and High-Speed RAM Write Operations
Normal RAM Write
(HWM=0)
Can be used
Can be used
Can be used
Can be used
Can be specified by word
Can be read by word
Can be written by word
Can be set by word
41
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
Dummy write operations may have to be
inserted according to a window address-
range specification
Can be set by word
HD66765