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4: FUNCTION DESCRIPTION
4.1.6
Determining Various Parameters
(1) Determining FX
Determine the character field size in the X direction [FX] from the number of dots in the X direction of
display [VD] and the number of characters in the X direction [VC].
[VD] / [VC] ≤ [FX]
The brackets [ ] denote an integral value beginning with 1, and [FX] indicates the number of dots.
(2) Determining C/R
Next, determine a value for [C/R] from the values of [VC] and [FX].
[C/R] = | [FX] / 8 | rounded up x [VC]
Note: [C/R] indicates the number of characters obtained in units of addresses.
(3) Determining TC/R
TC/R must maintain the relationship [TC/R] ≥ [C/R] + 4.
(4) Relationship between f
Once TC/R has been determined, the lower-limit value of the oscillation frequency (f
from the equation below because the frame frequency (f
predetermined.
≥ {[TC/R] x 9 + 1} x [L/F] x f
f
OSC
Note: 1. If standard crystals close to f
ate f
do so, reverse the calculation of the [TC/R] value in the equation above.
2. For the f
(5) Symptoms observed when TC/R is set incorrectly
• Scanning of display in the Y direction stops, with horizontal lines displayed in high contrast.
• All pixels go on or go off.
• The LP pin output signal is incomplete or inactive.
• The display of graphics or text becomes unstable.
Should any of the symptoms above be observed, even though the S1D13700's other signals connected to
the LCD unit are normal, check whether the TC/R value is correct. If the TC/R value is the cause of the
problem, simply set a larger TC/R value to restore normal operation.
Number of pixels
(X x Y)
e.g., [FX] = 8 dots
320 ÷ 8 = 40...0
320 x 240
No blank dots
e.g., [FX] = 6 dots
320 ÷ 6 = 53...2
Two blank dots
Note: 1. Because the number of display dots varies with each LCD unit, there will be some frac-
tional display dots depending on the value set for FX. In such case, the S1D13700 auto-
matically blanks fractional parts at the right edge of the panel, and thus eliminates the
need to manipulate display memory for adjustment.
2. Calculations are made assuming f
64
and f
OSC
FR
value for crystals with higher oscillation frequencies than the obtained value. To
OSC
value of Epson LCD units, refer to the LCD unit specifications.
FR
Table 4-2 Example of Parameters for the LCD Unit
[FX]
[FY]
From a practical
point of view, 8, 16,
etc. are suitable.
↑
) and number of display lines [L/F] are
FR
FR
thus obtained are unavailable, determine the appropri-
OSC
[C/R]
[CR] = 40 = address → 27H
During HDOT SCR, [C/R] = 41 addresses
[CR] = 53 = address → 34H
During HDOT SCR, [C/R] = 54 addresses
= 60 Hz.
FR
EPSON
) can be obtained
OSC
X'tal
TC/R
(MHz)
2BH
5.72
38H
7.40
S1D13700 Technical Manual
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