Texas Instruments TMS320DM646X DMSOC User Manual

Page 47

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Use Cases

Since the value of the W_SETUP/R_SETUP, W_STROBE/R_STROBE, W_HOLD/R_HOLD, and TA fields
are equal to EMIF clock cycles minus 1 cycle, the A1CR should be configured as in

Table 30

. In this

example, although the EM_WAIT signal is connected to the R/B signal of the NAND Flash the Extended
Wait mode of the EMIF is not used, therefore the asynchronous wait cycle configuration register (AWCCR)
does not need to be programmed.

Table 30. Configuring A1CR for HY27UA081G1M Example

Parameter

Setting

SS

Select Strobe mode.

• SS = 0. Places EMIF in Normal Mode.

EW

Extended Wait mode enable.

• EW = 0. Disabled Extended wait mode.

W_SETUP/R_SETUP

Read/Write setup widths.

• W_SETUP = 0

• R_SETUP = 2

W_STROBE/R_STROBE

Read/Write strobe widths.

• W_STROBE = 6

• R_STROBE = 7

W_HOLD/R_HOLD

Read/Write hold widths.

• W_HOLD = 1

• R_HOLD = 0

TA

Minimum turnaround time.

• TA = 2

ASIZE

Asynchronous device bus width.

• ASIZE = 0, select an 8-bit data bus width.

Since this is a NAND Flash example, the EMIF must be configured for NAND Flash mode. This is
accomplished by configuring the NAND Flash control register (NANDFCR) as in

Table 31

. In NANDFCR,

chip select space 2 must be configured with NAND Flash mode enabled.

Table 31. Configuring NANDFCR for HY27UA081G1M Example

Parameter

Setting

CS5ECC

NAND Flash ECC start for chip select 5.

• CS5ECC = 0. Not set during configuration. Only set just prior to reading or writing data.

CS4ECC

NAND Flash ECC start for chip select 4.

• CS4ECC = 0. Not set during configuration. Only set just prior to reading or writing data.

CS3ECC

NAND Flash ECC start for chip select 3.

• CS3ECC = 0. Not set during configuration. Only set just prior to reading or writing data.

CS2ECC

NAND Flash ECC start for chip select 2.

• CS2ECC = 0. Not set during configuration. Only set just prior to reading or writing data.

CS5NAND

NAND Flash mode for chip select 5.

• CS5NAND = 0. NAND Flash mode is disabled.

CS4NAND

NAND Flash mode for chip select 4.

• CS4NAND = 0. NAND Flash mode is disabled.

CS3NAND

NAND Flash mode for chip select 3.

• CS3NAND = 0. NAND Flash mode is disabled.

CS2NAND

NAND Flash mode for chip select 2.

• CS5NAND = 1. NAND Flash mode is enabled.

47

SPRUEQ7C – February 2010

Asynchronous External Memory Interface (EMIF)

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