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7-42 Intel® PXA26x Processor Family Developer’s Manual
Liquid Crystal Display Controller
Note: In dual-panel mode, write to both FBR0 and FBR1 in order to branch properly.
7.6.7 LCD Controller Status Register (LCSR)
The read/write LCD Controller Status Register, described in Table 7-12, contains bits that signal:
• Underrun errors for both the input and output FIFOs
• AC bias pin transition count
• LCD disable and quick disable
• DMA start/end frame and branch status
• DMA transfer bus error conditions.
Unless masked, each of these hardware-detected events signals an interrupt request to the interrupt
controller. Two bits, BER and ABC, generate nonmaskable interrupts.
Each of the LCD’s status bits continues to signal an interrupt request for as long as the bit is set.
Once the bit is cleared, the interrupt is cleared. Status bits are referred to as sticky (once set by
hardware, they must be cleared by software). Writing one to a sticky status bit clears it. Writing
zero has no effect. All LCD interrupts can be masked by programming the Interrupt Controller
Mask Register (ICMR). See Section 4.2, “Interrupt Controller” on page 4-22 for more details.
Write reserved bits with zeros and ignore reads from reserved bits.
Table 7-11. LCD DMA Frame Branch Registers (FBRx)
Physical Address
channel 0: 0x4400_0020
channel 1: 0x4400_0024
LCD DMA Frame Branch Registers LCD Controller
Bit
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Frame Branch Address
Reserved
BINT
BRA
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 X X 0 0
Bits Name Description
31:4
Frame
Branch
Address
FRAME BRANCH ADDRESS:
Address of the descriptor for the branched-to frame.
3:2 — Reserved
1BINT
BRANCH INTERRUPT:
0 – Do not set the BS interrupt bit in register LCSR after the branched-to descriptor is
loaded.
1 – Set the BS interrupt bit in register LCSR after the branched-to descriptor is loaded.
0BRA
BRANCH:
0 – Do not branch after finishing the current frame.
1 – Branch after finishing the current frame. The next descriptor is fetched from the Frame
Branch Address. BRA is automatically cleared after loading the new descriptor.