RM0082
RS_Color liquid crystal display controller (CLCD)
Doc ID 018672 Rev 1
763/844
It is possible to clear the interrupt by writing a logic ‘1’ to the LNBU bit in the LCDICR
Register.
33.7.4 CLCDFUFINTR
The FIFO underflow interrupt is asserted when internal data is requested from an empty
DMA FIFO. Internally, individual upper and lower panel DMA FIFO underflow interrupt
signals are generated and CLCDFUFINTR is the single combined version of these.
It is possible to clear the interrupt by writing a logic ‘1’ to the FUF bit in the LCDICR Register.
33.7.5
LCD powering up and powering down sequence support
The PrimeCell CLCD (PL110) enables the following power up sequence:
1.
Vdd is simultaneously applied to the SoC that contains the CLCD and panel display
driver logic. The signals
CLLP
,
CLCP
,
CLFP
,
CLAC
,
CLD[23:0]
, and
CLLE
are held
LOW.
2. When Vdd is stabilized, a logic ‘1’ is written to the LcdEn bit in the LCDControl
Register. This puts the signals
CLLP
,
CLCP
,
CLFP
,
CLAC
, and
CLLE
into their active
states but the
CLD[23:0]
signals remain LOW.
3.
When the signals in Step 2 have stabilized, where appropriate, the contrast voltage Vee
(this is not controlled or supplied by the CLCD) is then applied.
4. You can use a software timer routine, if required, 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 within the LcdControl Register which, in turn, sets
the
CLPOWER
signal HIGH and puts the
CLD[23:0]
signals into their active state. The
CLPOWER
signal is expected to be used to gate the power to the LCD panel.
The power down sequence is the reverse of the above four stages and must be strictly
followed, this time write the relevant register bits with logic ‘0’.
The power up and power down sequences are shown in
Figure 80: Power up & power down
Figure 80.
Power up & power down sequences
Mn(display
specific)mSec
(Provided through SW)
Mn(display
specific)mSec
(Provided through SW)
LCD On
Sequence
Min 0 ms
Min 0 ms
Minimum 0 ms
Minimum 0 ms
LCD Off Sequence
V
DD
V
EE
CLPOWER,
CLD[23:0]
CLLP,CLCP,CL
FP,CLAC,CLLE