at91sam9260-cj ATMEL Corporation, at91sam9260-cj Datasheet - Page 767

• Manufacturer Part Number: at91sam9260-cj
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

44.3.2
44.3.2.1
44.3.3
44.3.3.1
44.3.3.2
44.3.3.3
6221G–ATARM–31-Jan-08
EMAC
MCI
TX underrun may occur in some cases
Busy signal of R1b responses is not taken in account
SDIO interrupt does not work for slot different from A
Data Timeout Error Flag
EMACB FIFO internal arbitration scheme is :
EMACB master interface releases the AHB bus between two transfers.
EMACB has the highest priority.
If EMACB RX and TX FIFOs both have pending requests, the following sequence occurs:
In case of a slow memory and/or a special operation like SDRAM refresh or SDRAM bank open-
ing, a TX underrun may occur. (latency min 960 ns).
Reduce re-arbitration time between RX & TX EMACB transfers by using internal SRAM (or
another memory slave with a short access time) to transmit buffers and descriptors.
The busy status of the card during the response (R1b) is ignored for the commands CMD7,
CMD28, CMD29, CMD38, CMD42, CMD56. Additionally, for commands CMD42 and CMD56 a
conflict can occur on data line0 if the MCI sends data to the card while the card is still busy.The
behavior is correct for CMD12 command (STOP_TRANSFER).
None
If the data bus width is 1 bit and slots other than slot A chosen, the SDIO interrupt can not be
captured. The sample is made on the bad data line.
None
As the data Timeout error flag checking the Naac timing cannot rise, the MCI can be stalled wait-
ing indefinitely the Data start bit.
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 releases the AHB bus
3. The AHB matrix can grant an another master (ARM I or D for example)
4. AHB matrix re-arbitration (finishes at least the current word/halfword/byte)
5. The AHB matrix grants the EMACB
6. The EMACB TX FIFO read (burst 4)
Problem Fix/Workaround
Problem Fix/Workaround
Problem Fix/Workaround
AT91SAM9260
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