HD66773R Datasheet, PDF (69/133 Pages) Renesas Technology Corp – 262,144-color, 132 x 176-dot Graphics Controller Driver for TFT LCD panels

HD66773R
Conditions on using high-speed RAM write mode
1. The logical/compare operations are not available.
2. RAM write operation is executed every four words. Set the lower 2 bits of the addresses as follows
when setting addresses.
*When ID0=0, the lower two bits in the address must be set to 11 before RAM write.
*When ID0=1, the lower two bits in the address must be set to 00 before RAM write.
3. RAM write operation is executed every four words. If RAM write operation is terminated before all
four-word data is written to RAM, the last data will not be written to RAM.
4. When the index register is set to R22H (RAM data write), the first RAM write operation is always
executed. In this case, the RAM data read is not operable simultaneously. During RAM read, set the
HWM to 0.
5. The high-speed RAM write mode is not compatible with the normal RAM write mode. When the
mode must be switched to the other, make a new address setting before starting RAM write.
6. When writing data in high speed RAM write mode within the range specified with the window address,
some window-address range may require dummy write operation. See “High-Speed RAM Write with
Window Address Function”.
Comparison between Normal and High-Speed RAM Write Operations
Logical operation
Compare operation
BGR function
Write mask function
RAM address set
RAM read
RAM write
Window address
AM Setting
Normal RAM Write (HWM=0)
Available in 8-/16-bit interface
Available in 8-/16-bit interface
Available
Available in 8-/16-bit interface
Specified by one word
Read by one word
Write by one word
Set by one word
AM = 1/0
High-Speed RAM Write (HWM=1)
Not available
Not available
Available
Available
ID0 bit=0: Set the lower two bits to 11
ID0 bit=1: Set the lower two bits to 00
Not available
Some window-address range may require
insertion of dummy write
Horizontal range(HSA/HSE): 4 word or more
Number of horizontal writing : 4N (N>=2)
AM = 0
Rev.1.10, Jun.21.2003, page 69 of 133