r8a77850anbg Renesas Electronics Corporation., r8a77850anbg Datasheet - Page 983

• Manufacturer Part Number: r8a77850anbg
• Description: Renesas 32-bit Risc Microcomputer Superh? Risc Engine Family
• Manufacturer: Renesas Electronics Corporation.

19.4.15 Double Buffer Control
The double buffer control of the display unit (DU) includes two types of functions, which are a
manual display change mode in which display switching is all controlled by software, and an auto
display change mode to realize blinking.
In the case of manual display change mode, the display change is performed in frame units for
non-interlaced and interlaced sync display, and in field units for interlaced sync & video display.
In the case of auto display change mode, all switching is performed in field units.
Manual Display Change Mode: In manual display change mode, display frame switching is
controlled by software. Display switching can either be performed by software using the PnDC bit
in PnMR, or by setting the buffer 0 or buffer 1 start address in PnDSA0R and PnDSA1R indicated
by the DFBn bit in DSSR.
When making a transition from this mode to another mode, the PnDC bit should always be set to 1
first.
The following shows a control example for the manual display mode.
Auto Display Change Mode: For information on the auto display change mode, refer to section
19.4.11, Blinking.
CPU operation
Display screen
operation
VSYNC
(Non-interlaced)
Interrupt
processing
First frame
Transfer of display data for A1
A0 display
Second frame
A0 display
Interrupt
processing
VBK: VBK bit in DSSR
Rev.1.00 Jan. 10, 2008 Page 953 of 1658
Interrupt
processing
A0: Display area start address 0
A1: Display area start address 1
Display is switched by
the PnDC bit or DSAR
at the falling edge of VSYNC.
Transfer of display data for A0
Third frame
A1 display
19. Display Unit (DU)
REJ09B0261-0100