AT91SAM9261S_1 Datasheet, PDF (681/709 Pages) ATMEL Corporation – AT91 ARM Thumb-based Microcontrollers

AT91SAM9261S
42.3.3 Boot ROM
42.3.3.1
Boot ROM: Temperature Range
The temperature range for the Boot ROM use is 0°C / 70°C.
Starting up the device outside this temperature range can lead to unpredictable behavior. If the
AT91SAM9261S-based system may have to start up at temperatures below 0⋅ C and above
70⋅ C, it is recommended to boot out of an external memory connected on NCS0.
Problem Fix/Workaround
None.
42.3.4 Bus Matrix
42.3.4.1
Bus Matrix: Problem with Locked Transfers
Locked transfers are not correctly handled by the Bus Matrix and can lead to a system freeze
up. This does not concern ARM locked transfers.
Problem Fix/Workaround
Avoid other Bus Matrix masters locked transfers.
42.3.5 LCD
42.3.5.1
LCD: Screen shifting after a reset
When a FIFO underflow occurs, a reset of the LCD DMA and FIFO pointers is necessary.
If only LCD DMA pointers are reset (FIFO pointers not reset), the displayed image is shifted.
Problem Fix/Workaround
Apply the following sequence to correctly reset LCD DMA and FIFO pointers:
• LCD power off
• DMA disable
• Wait for DMABUSY
• DMA reset
• LCD power on
• DMA enable.
Powering LCD off, then powering LCD on, resets the FIFO pointers.
Disabling DMA, then enabling DMA, resets the DMA pointers.
42.3.5.2
LCD: Periodic bad pixels
LCD periodic bad pixels is due to mis-aligned DMA base address in frame buffer. LCD DMA per-
forms bursts to read memory. The LCD DMA bursts must not cross the 1-Kbyte AMBA
boundary.
Problem Fix/Workaround
The LCD DMA burst size in 32-bit words is programmed by BRSTLN field in DMAFRMCFG
register.
The LCD DMA Base Address is programmed in DMABADDR1 register.
The LCD DMA Base Address must be programmed with a value aligned onto LCD DMA burst
size, e.g.:
6242E–ATARM–11-Sep09
681