at91sam9263 ATMEL Corporation, at91sam9263 Datasheet - Page 931

• Manufacturer Part Number: at91sam9263
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

Figure 44-14. Command Queuing
6249D–ATARM–20-Dec-07
CPU WRITE
Recommended Procedure for Using the Command Queue
ADDRESS = 0x08
BUF END = 64
LENGTH = 9
2DGC FIFO
SBXR
SBXR
SBYR
TEXR
TEYR
GOR
LWR
CSR
LOR
LPR
In order to optimize the small command FIFO (64 half words) use, and due to the restriction of
the APB access that has to be full word only, all 32-bit registers are split into two registers. This
only affects the clipping command where the start and end coordinates of the line to be clipped
could be outside the range of 2048 pixels and may need 32 bits to define line coordinates. Thus
extra accesses to the FIFO must be made if the clip line coordinate has to be represented in 32
bits versus 16 bits. See the specific example of clipping command that shows the change in
code as described above.
• Load the entire queue (equal to 64) with commands.
• Enable command queue buffer empty interrupt (BUFE) in 2DGC_GMR if using interrupts
instead of polling.
READ FIFO
DRAW QUEUE
CONTROL
AT91SAM9263 Preliminary
WRITE TO REG
2DGC REGISTERS
SBXR
SBYR
TEXR
TEYR
GOR
LWR
CSR
LPR
LOR
RENDER LINE
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