M30218 Datasheet, PDF (65/179 Pages) Mitsubishi Electric Semiconductor – M30218 Group

FLD controller
Mitsubishi microcomputers
M30218 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Timing setting
Each timing is set by the FLDC mode register, Tdisp time set register, Toff1 time set register, and Toff2 time set register.
•Tdisp time setting
The Tdisp time represents the length of display timing. In non-gradation display mode, it consists of a
FLD display output period and a Toff1 time. In gradation display mode, it consists of the display output
period and Toff1 time plus a low signal output period for dark display. Set the Tdisp time by the Tdisp
counter count source select bit of the FLDC mode register and the Tdisp time set register. Supposing that
the value of the Tdisp time set register is n, the Tdisp time is represented as Tdisp = (n+1) x t (t: count
source). When the Tdisp counter count source select bit of the FLDC mode register is “0” and the value
of the Tdisp time set register is 200 (C816), the Tdisp time is: Tdisp = (200+1) x 3.2 (at XIN= 10 MHz) =
643 µs. When reading the Tdisp time set register, the value in the counter is read out.
•Toff1 time setting
The Toff1 time represents a non-output (low signal output) time to prevent blurring of FLD, and to dim the
display. Use the Toff1 time set register to set this Toff1 time. Make sure the value set to Toff1 is smaller
than Tdisp and Toff2. Supposing that the value of the Toff1 time set register is n1, the Toff1 time is
represented as Toff1 = n1 x t. When the Tdisp counter count source select bit of the FLDC mode register
is “0” and the value of the Toff1 time set register is 30 (1E16), Toff1 = 30 x 3.2 (at XIN = 10 MHz) = 96 µs.
•Toff2 time setting
The Toff2 time is provided for dark display. For bright display, the FLD display output remains effective
until the counter that is counting Tdisp reaches the terminal count. For dark display, however, “L” (or “off”)
signal is output when the counter that is counting Toff2 reaches the terminal count. This Toff2 time setting
is valid only for FLD ports which are in the gradation display mode and whose gradation display control
RAM value is “1” .
Set the Toff2 time by the Toff2 time set register. Make sure the value set to Toff2 is smaller than Tdisp but
larger than Toff1. Supposing that the value of the Toff2 time set register is n2, the Toff2 time is repre-
sented as Toff2 = n2 x t. When the Tdisp counter count source select bit of the FLDC mode register is “0”
and the value of the Toff2 time set register is 180 (B416), Toff2 = 180 x 3.2 (at XIN = 10 MHz) = 576 µs.
Low output period for
blurring prevention Display output period
•Grayscale display mode is not selected
(Address 035016 bit 5 = “0”)
•Grayscale display mode is selected and set for bright display
(Address 035016 bit 5 = “1” and the corresponding grayscale
display control data = “0”)
Toff1
Tdisp
Low output period for
blurring prevention
Display output
period
Low output period for
dark display
•Grayscale display mode is selected and set for dark display
(Address 035016 bit 5 = “1” and the corresponding grayscale
display control data = “1”)
Figure KA-11. FLDC Timing
64
Toff1
Toff2
Tdisp