Atmel Evaluation Kit AT91SAM9M10-G45-EK AT91SAM9M10-G45-EK Data Sheet

 690

SAM9M10 [DATASHEET]

6355F–ATARM–12-Mar-13

g.

Program LLI_W(n).DMAC_CTRLBx with the following field’s values:

–DST_INCR is set to INCR

–SRC_INCR is set to INCR

–FC field is programmed with peripheral to memory flow control mode.

–SRC_DSCR is set to 0. (descriptor fetch is enabled for the SRC)

–DST_DSCR is set to TRUE. (descriptor fetch is disabled for the DST)

–DIF and SIF are set with their respective layer ID. If SIF is different from DIF, the DMA Controller is 

able to prefetch data and write HSMCI simultaneously.

h.

Program LLI_W(n).DMAC_CFGx register for channel x with the following field’s values:

–FIFOCFG defines the watermark of the DMA channel FIFO.

–DST_REP is set to zero. Address are contiguous.

–SRC_H2SEL is set to true to enable hardware handshaking on the destination.

–SRC_PER is programmed with the hardware handshaking ID of the targeted HSMCI Host 

Controller.

i.

Program LLI_W(n).DMAC_DSCRx with the address of LLI_W(n+1) descriptor. And set the DSCRx_IF 
to the AHB Layer ID. This operation actually links descriptors together. If LLI_W(n) is the last descrip-
tor then LLI_W(n).DMAC_DSCRx points to 0.

j.

Program DMAC_CTRLBx register for channel x with 0. its content is updated with the LLI Fetch 
operation.

k.

Program DMAC_DSCRx register for channel x with the address of LLI_W(0).

l.

Enable Channel x writing one to DMAC_CHER[x]. The DMAC is ready and waiting for request.

5.

Poll CBTC[x] bit in the DMAC_EBCISR Register.

6.

If a new list of buffers shall be transferred repeat step 7. Check and handle HSMCI errors.

7.

Poll FIFOEMPTY field in the HSMCI_SR. 

8.

Send The STOP_TRANSMISSION command writing the HSMCI_ARG then the HSMCI_CMDR.

9.

Wait for XFRDONE in HSMCI_SR register.

The High Speed MultiMedia Card Interface allows processing of SD Memory (Secure Digital Memory Card) and
SDIO (SD Input Output) Card commands.

SD/SDIO cards are based on the Multi Media Card (MMC) format, but are physically slightly thicker and feature
higher data transfer rates, a lock switch on the side to prevent accidental overwriting and security features. The
physical form factor, pin assignment and data transfer protocol are forward-compatible with the High Speed Multi-
Media Card with some additions. SD slots can actually be used for more than flash memory cards. Devices that
support SDIO can use small devices designed for the SD form factor, such as GPS receivers, Wi-Fi or Bluetooth
adapters, modems, barcode readers, IrDA adapters, FM radio tuners, RFID readers, digital cameras and more.

SD/SDIO is covered by numerous patents and trademarks, and licensing is only available through the Secure Dig-
ital Card Association.

The SD/SDIO Card communication is based on a 9-pin interface (Clock, Command, 4 x Data and 3 x Power lines).
The communication protocol is defined as a part of this specification. The main difference between the SD/SDIO
Card and the High Speed MultiMedia Card is the initialization process.

The SD/SDIO Card Register (HSMCI_SDCR) allows selection of the Card Slot and the data bus width.

The SD/SDIO Card bus allows dynamic configuration of the number of data lines. After power up, by default, the
SD/SDIO Card uses only DAT0 for data transfer. After initialization, the host can change the bus width (number of
active data lines).