Toshiba TLCS-900/H1 Series Manual page 350

(2) Refresh rate adjust function (Correct function)
LCDSCC<SCC7:0> and FP [9:0] register. The FFP value is normally set at the
same value as the ROW number, but this value can be used for correction of BCD
frequency: refresh rate.
frequency. The LCDC cannot operate correctly if a value smaller than the ROW
number is set.
Example:
Value of setting to register is only integer, SCC = 17. The floating value is disregarded.
In this case, refresh rate comes to 144.6 [Hz]
FP value is adjusted to set SCC=17 in above equation again.
Value of setting to register is only integer, FP = 496.
In this case, refresh rate comes to 140.0 [Hz]
LCDFFP Bit symbol
(0282H)
Read/Write
Reset State
Function
Reference) We recommend refresh rate values in the region of:...
In this function, the LBCD frequency: refresh rate is generated by setting
This function always uses a value greater than the ROW number, set to slower
The following is an example of settings:.
[Hz] = 20 MHz, 480COM ( FP = 480 ), Target refresh rate = 140 Hz
f
SYS
140 [Hz] = 20000000 [Hz]/((SCC+1) × 16 × 480)
(SCC+1) = 20000000/(140 × 16 × 480) = 18.60
[Hz] = f [Hz]/((SCC+1) × 16 × FP)
f
BCD SYS
140 [Hz] = 20000000/(18 × 16 × FP)
FP = 496.03
LCD f
7 6 5
FP7 FP6 FP5
0 0 0
Monochrome: 70 [Hz]
4, 8, 16 grayscales and color: 140 to 200 [Hz]
92CH21-348
Register
FP
4 3
FP4 FP3
R/W
0 0
Setting bit7 to bit0 for f
FP
TMP92CH21
2 1 0
FP2 FP1 FP0
0 0 0
2009-06-19