HD66787 Datasheet, PDF (108/159 Pages) Renesas Technology Corp – 528-channel, One-chip Driver with 262,144-color Display RAM and Power Supply Circuit for Low-temperature Poli-Si TFT (LTPS-TFT) Panels with Incorporat

HD66787
Preliminary
Comparison of Normal and High-Speed RAM Write Operations
Logical operation function
Compare operation function
BGR function
Write mask function
RAM address set
RAM read
RAM write
Window address
External display interface
AM Setting
Normal RAM Write
(HWM=0)
Available
Available
Available
Available
Specified by one
word
Read by one word
Write by one word
Set by one word
Available
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
Dummy write operations may be required depending
on the specified window-address range
Horizontal range(HSA/HSE): more than four words
Number of horizontal writing : 4N (N>=2)
Available
AM = 0
High-Speed RAM Write with Window Address Function
To rewrite the data in an arbitrary rectangular area of RAM consecutively in high speed, the number of
RAM access should be made 4 multiple times. Accordingly some window-address range may require
dummy write operation to make the RAM access 4 multiple times. The number of dummy write is set
when setting the window address as follows.
The horizontal window-address range specifying bits (HSA1-0, HEA1-0) specify the number of dummy
write operations executed at the start and end of the data to write to RAM. The total RAM access must be
4 multiple times per line.
Number of Dummy Write Operations in High-Speed RAM Write (HSA Bits)
HSA1
0
0
1
1
HSA0
0
1
0
1
Number of Dummy Write Operations
inserted
0
1
2
3
Rev.0.22, May.23.2003, page 108 of 159