MITSUBISHI MICROCOMPUTERS
M37274EFSP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
and ON-SCREEN DISPLAY CONTROLLER
(1) Dual Layer OSD
M37274MA-XXXSP has 2 layers; layer 1 and layer 2. These layers
display the OSD for controlling TV and the closed caption display at
the same time and overlayed on each other.
Layer 2
Each block can be assigned to either layer by bits 6 and 5 of the
block control register (refer to Figure 65). For example, only when
both bits 5 and 6 are “1,” the block is assigned to layer 2. Other bit
combinations assign the block to layer 1.
Block 9
Block 10
Block 11
Block 12
When a block of layer 1 is overlapped with that of layer 2, a screen is
combined (refer to Figure 67) by bits 7 and 6 of the OSD control
register (refer to Figure 64).
Block 1
Block 2
Block
Note: When using the dual layer OSD, note Table 11.
Block 7
Block 8
Block
Layer 1
Fig. 66. Image of Dual Layer OSD
Table 11. Conditions of Dual Layer
Block
Block in Layer 1
Block in Layer 2
Parameter
Display mode
OSD Clock source
Pre-divide ratio
CC mode
OSD mode
Same as layer 1
Data slicer clock or OSC1 or main clock
✕ 1 or ✕ 2 (all blocks)
Same as layer 1 (Note)
Pre-divide ratio = 1
Pre-divide ratio = 2
1TC ✕ 1/2H, 1.5TC ✕ 1/2H
1TC ✕ 1H, 1.5TC ✕ 1H
Dot size
1TC ✕ 1/2H
1TC ✕ 1/2H
1TC ✕ 1H
Horizontal display start position
Arbitrary
Same position as layer 1
Note: For the pre-divide ratio of the layer 2, select the same as the layer 1’s ratio by bit 6 of the clock control register.
Display example of layer 1 = “HELLO,” layer 2 = “CH5”
CH5
HELLO
CH5
HELLO
CH5
HELLO
Logical sum (OR) of
layer 1’s color and
layer 2’s color
Layer 1’s color has priority Layer 2’s color has priority
Bit 7 = “0”, bit 6 = “1” Bit 7 = “1,” bit 6 = “0”
Bit 7 = “0,” bit 6 = “0”
Fig. 67. Display Example of Dual Layer OSD
68
RENESAS [ RENESAS TECHNOLOGY CORP ]
