EMIF

EMIF

External Memory Interface (EMIF) The asynchronous External Memory Interface (EMIF) is a TI IC bus used in their Digital Signal Processors (DSP) and Digital Media System-on-Chip (DMSoC). For example; used on the TMS320DM646x by TI.

The EMIF bus provides a means to connect to a variety of external devices including: NAND Flash, Asynchronous devices including Flash and SRAM, Host processor interfaces such as the host port interface (HPI) on a Texas Instruments Digital Signal Processor (DSP). The most common use for the EMIF is to interface with both flash devices and SRAM devices.

EMIF supporting interfaces:

24 addressable chip select spaces of up to 32MB each

8-bit and 16-bit data bus widths

Programmable cycle timings such as setup, strobe, and hold times as well as turnaround time

Select strobe mode

Extended Wait mode

NAND Flash ECC generation

Connecting as a host to a TI DSP HPI interface

Data bus parking

The EMIF easily interfaces to a variety of asynchronous devices including Flash and ASRAM. The EMIF can be operated in three major modes:Normal modeSelect Strobe (SS) modeNAND Flash mode

The behavior of the EM_CS signal is the single difference between Normal mode and Select Strobe mode. In Normal mode, the EM_CS signal becomes active at the beginning of the setup period and remains active for the duration of the transfer. In Select Strobe mode, the EM_CS signal functions as a strobe signal, active only during the strobe period of an access.

In NAND Flash mode, the EMIF hardware is able to calculate the error correction code (ECC) for each 512 byte data transfer. In addition to the three modes of operation, the EMIF also provides configurable cycle timing parameters and an Extended Wait mode that allows the connected device to extend the strobe period of an access cycle.

The EMIF always drives the data bus to the previous write data value when it is idle. This feature is called data bus parking. Only when the EMIF issues a read command to the external memory does it stop driving the data bus. After the EMIF latches the last read data, it immediately parks the data bus again.

EMIF may also refer to:
*Electro Magnetic Interference Filter
*Electronic Monitoring of Insect Feeding
*ESCON Multiple Image Facility (IBM)
*External Memory Interface (integrated circuits, microprocessors)