Example Configuration
889
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
External Memory Interface A (EMIFA)
Since the value of the W_SETUP/R_SETUP, W_STROBE/R_STROBE, W_HOLD/R_HOLD, and TA fields
are equal to EMIFA clock cycles minus 1 cycle, the CE3CFG should be configured as in
. In
this example, the EMA_WAIT signal is not implemented; therefore, the asynchronous wait cycle
configuration register (AWCC) does not need to be programmed.
Table 19-39. Configuring CE3CFG for TC5516100FT-12 Example
Parameter
Setting
SS
Select Strobe mode.
• SS = 0. Places EMIFA 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 = 0
W_STROBE/R_STROBE
Read/Write strobe widths.
• W_STROBE = 0
• R_STROBE = 0
W_HOLD/R_HOLD
Read/Write hold widths.
• W_HOLD = 0
• R_HOLD = 0
TA
Minimum turnaround time.
• TA = 0
ASIZE
Asynchronous Device Bus Width.
• ASIZE = 1, select a 16-bit data bus width
19.3.2.3 Interfacing to NAND Flash
The following example explains how to interface the EMIFA to the Hynix HY27UA081G1M NAND Flash
device.
19.3.2.3.1 Margin Requirements
The Flash interface is typically a low-performance interface compared to synchronous memory interfaces,
high-speed asynchronous memory interfaces, and high-speed FIFO interfaces. For this reason, this
example gives little attention to minimizing the amount of margin required when programming the
asynchronous timing parameters. The approach used requires approximately 10 ns of margin on all
parameters, which is not significant for a 100-ns read or write cycle. For additional details on minimizing
the amount of margin, see the ASRAM example given in
Table 19-40. Recommended Margins
Timing Parameter
Recommended Margin
Output Setup
10 nS
Output Hold
10 nS
Input Setup
10 nS
Input Hold
10 nS