
ViiiPeRiPheRaLMoDuLes6(LCD):LCDContRoLLeR(LCDC)
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Viii-1-7
VIII
LCDC
Viii.1.4.2settingtheLCDCClock
The CMU provides the clock paths with a control bit shown below for the LCDC. The clock supply turns on when
the control bit is set to 1 and it turns off when the control bit is set to 0.
(1)LCDCahBbusinterfaceclock(LCDC_ahBiF_CLK)
The LCDC uses this clock (MCLK) to access IVRAM (internal VRAM) or an SDRAM (external VRAM). This
clock is required for displaying a screen on the LCD panel. LCDCAHBIF_CKE (D2/0x301B00) is used for
clock supply control (default: off).
*LCDCahBiF_CKe:LCDCAHBBusInterfaceClockControlBitintheGatedClockControlRegister0
(D2/0x301B00)
(2)Controlregisterclock(LCDC_saPB_CLK)
This clock (MCLK) is used to control the LCDC registers located in area 6. This clock is required for accessing
the LCDC registers and it can be stopped otherwise. LCDCSAPB_CKE (D1/0x301B00) is used for clock sup-
ply control (default: off).
*LCDCsaPB_CKe:LCDCSAPBBusInterfaceClockControlBitintheGatedClockControlRegister0
(D1/0x301B00)
(3)iVRaMarbiterclock(iVRaM_aRB_CLK)
This clock (MCLK) is used when the LCDC or CPU accesses IVRAM. When IVRAM is configured as
A0RAM accessed by the CPU only, the clock supply can be stopped. IVRAMARB_CKE (D19/0x301B04) is
used for clock supply control (default: on).
*iVRaMaRB_CKe:IVRAMArbiterClockControlBitintheGatedClockControlRegister1(D19/0x301B04)
(4)LCDinterfaceclock(LCDC_CLK)
This is the LCD interface clock (LCDC_CLK) generated by dividing the OSC3 clock. The frequency divider
generates 16 kinds of clocks from OSC31/1 to OSC31/16. Select a divided clock according to the frame rate
using LCDCDIV[3:0] (D[19:16]/0x301B08).
fLCDC
Frame rate = ————— [Hz]
HT
× VT
fLCDC: LCDC_CLK frequency
HT: Horizontal total period (including non-display period) [pixels]
VT: Vertical total period (including non-display period) [pixels]
*LCDCDiV[3:0]:LCDCClockDividerSelectBitsintheSystemClockControlRegister(D[19:16]/0x301B08)
TableVIII.1.4.2.1SelectingtheLCDCClock
LCDCDiV3
1
0
LCDCDiV2
1
0
1
0
LCDC_CLK
OSC31/16
OSC31/15
OSC31/14
OSC31/13
OSC31/12
OSC31/11
OSC31/10
OSC31/9
OSC31/8
OSC31/7
OSC31/6
OSC31/5
OSC31/4
OSC31/3
OSC31/2
OSC31/1
LCDCDiV1
1
0
1
0
1
0
1
0
LCDCDiV0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
(Default:0b0111=OSC31/8)
LCDC_CKE (D0/0x301B00) is used for clock supply control (default: off).
*LCDC_CKe:LCDCMainClockControlBitintheGatedClockControlRegister0(D0/0x301B00)