Texas Instruments TMS320DM646X DMSOC User Manual

Page 11

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EM_CS[5:2]

EM_WE

EM_OE

EM_RW

EM_WAIT[5:2]

EM_BA[1:0]

EM_D[15:0]

EM_A[22:0]

EMIF

EM_D[7:0]

EM_A[21:0]

EM_BA[1:0]

DQ[7:0]

A[23:2]

A[1:0]

EMIF

8−bit

asynchronous

memory

a) EMIF to 8-bit memory interface

EM_D[15:0]

EM_A[21:0]

EM_BA[1]

DQ[15:0]

A[22:1]

A[0]

EMIF

16−bit

asynchronous

memory

b) EMIF to 16-bit memory interface

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Architecture

2.5.1

Interfacing to Asynchronous Memory

Figure 2

shows the EMIF's external pins used in interfacing with an asynchronous device. Of special note

is the connection between the EMIF and the external device's address bus. The EMIF address pin
EM_A[0] always provides the least significant bit of a 32-bit word address. Therefore, when interfacing to a
16-bit or 8-bit asynchronous device, the EM_BA[1] and EM_BA[0] pins provide the least-significant bits of
the halfword or byte address, respectively.

Figure 2

and

Figure 3

show the mapping between the EMIF

and the connected device's data and address pins for various programmed data bus widths. The data bus
width may be configured in the asynchronous configuration register (ACFGn).

Figure 2. EMIF Asynchronous Interface

Figure 3. EMIF to 8-bit and 16-bit Memory Interfaces

11

SPRUEQ7C – February 2010

Asynchronous External Memory Interface (EMIF)

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