Example Configuration
747
SPRUH91D – March 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
External Memory Interface A (EMIFA)
18.3.2.2.3 Example Using TC5516100FT-12
This section takes you through the configuration steps required to implement Toshiba’s TC55V1664FT-12
ASRAM with the EMIFA. The following assumptions are made:
•
ASRAM is connected to chip select space 3 (EMA_CS[3])
•
EMIFA clock speed is 100 MHz (t
cyc
= 10 nS)
lists the data sheet specifications for the EMIFA and
lists the data sheet
specifications for the ASRAM.
(1)
Depending on operating conditions. See your device-specific data manual for the value.
Table 18-36. EMIFA Timing Requirements for TC5516100FT-12 Example
Parameter
Description
Min
Max
Units
t
SU
Data Setup time, data valid before EMA_OE high
3 to 7
(1)
nS
t
H
Data Hold time, data valid after EMA_OE high
0
nS
Table 18-37. ASRAM Timing Requirements for TC5516100FT-12 Example
Parameter
Description
Min
Max
Units
t
ACC
Address Access time
12
nS
t
OH
Output data Hold time for address change
3
nS
t
RC
Read cycle time
12
nS
t
WP
Write Pulse width
8
nS
t
AW
Address valid to end of Write
9
nS
t
DS
Data Setup time
7
nS
t
WR
Write Recovery time
0
nS
t
DH
Data Hold time
0
nS
t
WC
Write Cycle time
12
nS
t
COD
Output Disable time from chip enable
7
lists the values of the PCB board delays. The delays were estimated using the rule that there
is 180 pS of delay for every 1 inch of trace.
Table 18-38. Measured PCB Delays for TC5516100FT-12 Example
Parameter
Description
Delay (ns)
Read Access
t
EM_CS
Delay on EMA_CS from EMIFA to ASRAM. EMA_CS is driven by EMIF.
0.36
t
EM_A
Delay on EMA_A from EMIFA to ASRAM. EMA_A is driven by EMIF.
0.27
t
EM_OE
Delay on EMA_OE from EMIFA to ASRAM. EMA_OE is driven by EMIF.
0.36
t
EM_D
Delay on EMA_D from ASRAM to EMIFA. EMA_D is driven by ASRAM.
0.45
Write Access
t
EM_CS
Delay on EMA_CS from EMIFA to ASRAM. EMA_CS is driven by EMIF.
0.36
t
EM_A
Delay on EMA_A from EMIFA to ASRAM. EMA_A is driven by EMIF.
0.27
t
EM_WE
Delay on EMA_WE from EMIFA to ASRAM. EMA_WE is driven by EMIF.
0.36
t
EM_D
Delay on EMA_D from EMIFA to ASRAM. EMA_D is driven by EMIF.
0.45