at91sam9263 ATMEL Corporation, at91sam9263 Datasheet - Page 1029

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

49.2.6
49.2.6.1
49.2.7
49.2.7.1
49.2.8
49.2.8.1
6249D–ATARM–20-Dec-07
ECC
EMACB
LCD
ECC status may be wrong with external SRAM
Transmit Underrun Errors
LCD Screen Shifting After a Reset
Problem Fix/Workaround
Check that all messages have been sent by reading the related Flags before entering Low-
power Mode .
When the data bus width is different for an SRAM on any EBI NCS and the NANDFlash, the
ECC status is wrong. A single error is seen as a multiple error and is not corrected.This does not
occur with SDRAM.
Problem Fix/Workaround
None.
EMACB FIFO internal arbitration scheme is:
EMACB master interface releases the AHB bus between two transfers.
EMACB has the highest priority.
If we are in a state where EMACB RX and TX FIFOs have requests pending, the following
sequence occurs:
In a case of a slow memory and/or a special operation such as SDRAM refresh or SDRAM bank
opening /closing, there may be TX underrun (latency min 960 ns).
Problem Fix/Workaround
Reduce re-arbitration time between RX and TX EMACB transfer by using internal SRAM (or
another slave with a short access time) for transmit buffers and descriptors.
When a FIFO underflow occurs, a reset of the DMA and FIFO pointers is necessary. Performing
the following sequence :
1. Receive buffer manager write
2. Receive buffer manager read
3. Transmit data DMA read
4. Receive data DMA write
5. Transmit buffer manager read
6. Transmit buffer manager write
1. EMACB RX FIFO write (burst 4)
2. EMACB release the AHB bus
3. The AHB matrix can grant an another master (ARM I or D for example)
4. AHB matrix re-arbitration (finish at least the current word/halfword/byte)
5. The AHB matrix grants the EMACB
6. The EMACB TX FIFO read (burst 4)
AT91SAM9263 Preliminary
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