RM0082
RS_Color liquid crystal display controller (CLCD)
Doc ID 018672 Rev 1
747/844
33.5.11 Bus
architecture
The CLCD incorporates a master and a slave interface.
The master interface is directly connected to a memory controller with an AMBA AHB slave
interface, while the slave interface is connected to the AMBA AHB bus.
AMBA AHB supports a wide range of on-chip bus sizes, from eight bits up to 1 024 bits. The
CLCD master and slave interfaces are implemented as 32 bit data bus devices only.
33.5.12
LCD powering up and down sequences
The CLCD requires the following power up sequence to be performed:
●
Vdd is simultaneously applied to the SoC that contains the CLCD peripheral and panel
display driver logic. The following signals are held LOW:
–
CLLP
–
CLCP
–
CLFP
–
CLAC
–
CLD[23:0]
–
CLLE.
●
When Vdd is stabilized, a logic ‘1’ is written to the LcdEn bit in the LCDControl
Register. (
) This enables the following signals into their active states:
–
CLLP
–
CLCP
–
CLFP
–
CLAC
–
CLLE
The CLD[23:0] signals remains low.
●
When the signals in step 2 have stabilized, where appropriate, the contrast voltage,
Vee (not controlled or supplied by the CLCD) is then applied.
●
If required, you can use a software timer routine to provide the minimum display
specific delay time between application of the control signals and power to the panel
display. On completion of the software timer routine, power is applied to the panel by
writing a logic ‘1’ to the LcdPwr bit in the LcdControl Register that, in turn, sets the
CLPOWER signal HIGH and enables the CLD[23:0] signals into their active states.
Normally, CLPOWER is used to gate the power to the LCD panel.
The power-down sequence is the reverse of the above four stages and you must follow it
strictly, this time, writing the respective register bits with logic ‘0’.