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6.10 External Memory Interface A (EMIFA)
EMIFA is one of two external memory interfaces supported on the C6745/6747. It is primarily intended to
support asynchronous memory types, such as NAND and NOR flash and Asynchronous SRAM. However
on C6745/6747 EMIFA also provides a secondary interface to SDRAM.
6.10.1 EMIFA Asynchronous Memory Support
EMIFA supports asynchronous:
•
SRAM memories
•
NAND Flash memories
•
NOR Flash memories
The EMIFA data bus width is up to 16-bits on the ZKB packageand 8 bits on the PTP package. Both
devices support up to fifteen address lines and an external wait/interrupt input. Up to four asynchronous
chip selects are supported by EMIFA (EMA_CS[5:2]) . All four chip selects are available on the ZKB
package. Two of the four are available on the PTP package (EMA_CS[3:2]).
Each chip select has the following individually programmable attributes:
•
Data Bus Width
•
Read cycle timings: setup, hold, strobe
•
Write cycle timings: setup, hold, strobe
•
Bus turn around time
•
Extended Wait Option With Programmable Timeout
•
Select Strobe Option
•
NAND flash controller supports 1-bit and 4-bit ECC calculation on blocks of 512 bytes.
6.10.2 EMIFA Synchronous DRAM Memory Support
The C6745/6747 ZKB package supports 16-bit SDRAM in addition to the asynchronous memories listed in
Section
6.10.1. It has a single SDRAM chip select (EMA_CS[0]). SDRAM configurations that are
supported are:
•
One, Two, and Four Bank SDRAM devices
•
Devices with Eight, Nine, Ten, and Eleven Column Address
•
CAS Latency of two or three clock cycles
•
Sixteen Bit Data Bus Width
•
3.3V LVCMOS Interface
Additionally, the SDRAM interface of EMIFA supports placing the SDRAM in Self Refresh and Powerdown
Modes. Self Refresh mode allows the SDRAM to be put into a low power state while still retaining memory
contents; since the SDRAM will continue to refresh itself even without clocks from the DSP. Powerdown
mode achieves even lower power, except the DSP must periodically wake the SDRAM up and issue
refreshes if data retention is required.
Finally, note that the EMIFA does not support Mobile SDRAM devices.
supported SDRAM configurations for EMIFA.
Copyright © 2008–2014, Texas Instruments Incorporated
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Product Folder Links:
TMS320C6745 TMS320C6747
TMS320C6745, TMS320C6747
SPRS377F – SEPTEMBER 2008 – REVISED JUNE 2014
Table 6-17
Peripheral Information and Electrical Specifications
below shows the
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