M37281MAH
–
XXXSP,M37281MFH
–
XXXSP,M37281MKH
–
XXXSP, M37281EKSP
Rev.1.01 2003.07.16 page 102 of 170
8.11.12 Multiline Display
This microcomputer can ordinarily display 16 lines on the CRT screen
by displaying 16 blocks at different vertical positions. In addition, it
can display up to 16 lines by using OSD interrupts.
An OSD interrupt request occurs at the point at which display of each
block has been completed. In other words, when a scanning line
reaches the point of the display position (specified by the vertical
position registers) of a certain block, the character display of that
block starts, and an interrupt occurs at the point at which the scan-
ning line exceeds the block. The mode in which an OSD interrupt
occurs is different depending on the setting of the OSD control regis-
ter 2 (refer to Figure 8.11.7).
When bit 7 of the OSD control register 2 is
“
0
”
An OSD interrupt request occurs at the completion of layer 1 block
display.
When bit 7 of the OSD control register 2 is
“
1
”
An OSD interrupt request occurs at the completion of layer 2 block
display.
Fig. 8.11.37 Note on Occurence of OSD Interrupt
Notes 1:
An OSD interrupt does not occur at the end of display when the block
is not displayed. In other words, if a block is set to off display by the
display control bit of the block control register i (addresses 00D0
16
to
00DF
16
), an OSD interrupt request does not occur (refer to Figure
8.11.37 (A)).
2:
When another block display appeares while one block is displayed,
an OSD interrupt request occurs only once at the end of the another
block display (refer to Figure 8.11.37 (B)).
3:
On the screen setting window, an OSD interrupt occurs even at the
end of the CC mode block (off display) out of window (refer to Figure
8.11.37 (C)).
(B)
(C)
Block 1 (on display)
Block 2 (on display)
Block 3 (on display)
Block 4 (on display)
Block 1 (on display)
Block 2 (on display)
Block 3 (off display)
Block 4 (off display)
“
OSD interrupt request
”
“
OSD interrupt request
”
“
OSD interrupt request
”
“
OSD interrupt request
”
“
OSD interrupt request
”
“
OSD interrupt request
”
No
“
OSD interrupt request
”
No
“
OSD interrupt request
”
Block 1
Block 2
“
OSD interrupt request
”
“
OSD interrupt request
”
“
OSD interrupt request
”
“
OSD interrupt request
”
Block 1
Block 2
Block 3
On display (OSD interrupt request occurs
at the end of block display)
Off display (OSD interrupt request does
not occur at the end of block display)
Window
No
“
OSD interrupt request
”
(A)