MITSUBISHI MICROCOMPUTERS
M37207MF-XXXSP/FP, M37207M8-XXXSP
M37207EFSP/FP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
and ON-SCREEN DISPLAY CONTROLLER
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(9) Scanning Line Double Count Mode
1 dot in a displayed character is normally shown with 1 scanning line.
In the scanning double count mode, 1 dot can be shown with 2 scan-
ning lines. As a result, the displayed dot is extended 2 times the
normal size in the vertical direction only (that is to say, the height of a
character is extended twofold.)
In addition, because the scanning line count is doubled, the display
start position of a character becomes also twofold position in the
vertical direction.
In other words, the contents of the vertical position register is as fol-
lows:
• In ordinary mode
256 steps as values “0016” to “FF16”
(4 scanning lines per step)
• In scanning line double count mode
128 steps as values “0016” to “7F16”
(8 scanning lines per step)
If the contents of the vertical position register for a block are set in
the range of “8016” to “FF16” in the scanning line double count mode,
that block cannot be displayed (not output to the CRT screen). The
scanning line double count mode is specified by setting bit 6 of the
CRT control register 1 (address 00EA16) to “1.”
Since this function works in units of a screen, even if the mode is
changed during display of 1 screen, the mode before the change
remains until the display of the next screen.
Fig. 62. Display in Ordinary Mode and in Scanning Line Double Count Mode
Scanning line 32 lines
A ✕ 2
Vertical position A ✕ 2
(a) Display in the ordinary mode (b) Display in the scanning line double count mode
Vertical position A
Scanning line 16 lines
