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Registers

4.18 MMC FIFO Control Register (MMCFIFOCTL)

The MMC FIFO control register (MMCFIFOCTL) is shown in Figure 39 and described in Table 25.

Figure 39. MMC FIFO Control Register (MMCFIFOCTL)

31

 

 

 

 

 

16

 

Reserved

 

 

 

 

 

 

R-0

 

 

 

 

15

5

4

3

2

1

0

Reserved

 

ACCWD

FIFOLEV

FIFODIR

FIFORST

R-0

 

 

R/W-0

R/W-0

R/W-0

R/W-0

LEGEND: R/W = Read/Write; R = Read only; -n= value after reset

Table 25. MMC FIFO Control Register (MMCFIFOCTL) Field Descriptions

Bit

Field

Value

Description

31-5

Reserved

0

Reserved

4-3

ACCWD

0-3h

Access width. Used by FIFO control to determine full/empty flag.

 

 

0

CPU/EDMA access width of 4 bytes

 

 

1h

CPU/EDMA access width of 3 bytes

 

 

2h

CPU/EDMA access width of 2 bytes

 

 

3h

CPU/EDMA access width of 1 byte

2

FIFOLEV

 

FIFO level. Sets the threshold level that determines when the EDMA request and the FIFO threshold

 

 

 

interrupt are triggered.

 

 

0

EDMA request every 128 bits sent/received.

 

 

1

EDMA request every 256 bits sent/received.

1

FIFODIR

 

FIFO direction. Determines if the FIFO is being written to or read from.

 

 

0

Read from FIFO.

 

 

1

Write to FIFO.

0

FIFORST

 

FIFO reset. Resets the internal state of the FIFO.

 

 

0

FIFO reset is disabled.

 

 

1

FIFO reset is enabled.

58

Multimedia Card (MMC)/Secure Digital (SD) Card Controller

SPRUE30B –September 2006

 

 

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Texas Instruments TMS320DM644x manual MMC Fifo Control Register Mmcfifoctl, Accwd Fifolev Fifodir Fiforst