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S3C2440A RISC MICROPROCESSOR MMC/SD/SDIO CONTROLLER
19-3
SDIO OPERATION
There are two functions of SDIO operation: SDIO Interrupt receiving and Read Wait Request generation. These two
functions can operate when RcvIOInt bit and RwaitEn bit of SDICON register is activated respectively. And two
functions have the steps and conditions like below.
SDIO Interrupt
In SD 1bit mode, Interrupt is received through all range from RxDAT[1] pin.
In SD 4bit mode, RxDAT[1] pin is shared between data receiving and interrupt receiving.
When interrupt detection range(Interrupt Period) is :
1. Single Block : the time between A and B
- A : 2clocks after the completion of a data packet
- B : The completion of sending the end bit of the next withdata command
2. Multi Block, PrdType = 0 : the time between A and B, restart at C
- A : 2clocks after the completion of a data packet
- B : 2clocks after A
- C : 2clocks after the end bit of the abort command response
3. Multi Block, PrdType = 1 : the time between A and B, restart at A
- A : 2clocks after the completion of a data packet
- B : 2clocks after A
- In case of last block, interrupt period begins at A, but not ends at B(CMD53 case)
Read Wait Request
Regardless of 1bit or 4bit mode, Read Wait Request signal transmits to TxDAT[2] pin in condition of below.
- In read multiple operation, request signal transmission begins at 2clocks after the end of the data
block
- Transmission ends when user sets to one RwaitReq bit of SDIDatSta register