M37221M6_03 Datasheet, PDF (44/62 Pages) Renesas Technology Corp – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER with ON-SCREEN DISPLAY CONTROLLER

MITSUBISHI MICROCOMPUTERS
M37221M6-XXXSP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
with ON-SCREEN DISPLAY CONTROLLER
(7) Multiline Display
The M37221M6-XXXSP can ordinarily display 2 lines on the CRT
screen by displaying 2 blocks at different vertical positions. In addi-
tion, it can display up to 16 lines by using CRT interrupts.
A CRT 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.
Note:
A CRT 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 with the display control bit of the CRT control reg-
ister (address 00EA16), a CRT interrupt request does not
occur (refer to Figure 45).
Block 1 (on display)
Block 2 (on display)
Block 1' (on display)
Block 2' (on display)
“CRT interrupt request”
“CRT interrupt request”
“CRT interrupt request”
“CRT interrupt request”
On display (CRT interrupt request occurs at the end of block
display)
Block 1 (on display)
Block 2 (on display)
Block 1' (off display)
Block 2' (off display)
“CRT interrupt request”
“CRT interrupt request”
No “CRT interrupt request”
No “CRT interrupt request”
Off display (CRT interrupt request does not occur at the end
of block display)
Fig. 45. Timing of CRT interrupt request
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