Tms320C6000 Sdram Activate (Actv) Command Before An Sdram Write Timing Diagram; Sdram Activation (Actv) - Texas Instruments TMS320C6000 DSP Reference Manual

SDRAM Interface
1.3.5

SDRAM Activation (ACTV)

Figure 1−4. TMS320C6000 SDRAM Activate (ACTV) Command Before an SDRAM Write
Timing Diagram
†
Clock
CEx
BE[3:0]
EA[15:0]
ED[31:0]
‡
SDA10
SDRAS
SDCAS
SDWE
†
Clock = SDCLK for C6201/C6701 DSP.
= CLKOUT2 for all C620x/C670x DSP, except C6201/C6701 DSP.
= ECLKOUT for C621x/C671x DSP.
= ECLKOUT1 for C64x DSP.
‡
SDA10 applies to C620x/C670x DSP only. On C621x/C671x DSP, EA12 is used. On C64x EMIFA, EA13 is used; on EMIFB,
EA11 is used.
1-12 Overview
The C6000 EMIF automatically issues the activate (ACTV) command before
a read or write to a new row of SDRAM. The ACTV command opens up a page
of memory, allowing future accesses (reads or writes) with minimum latency.
When the EMIF issues an ACTV command, a delay of t
a read or write command is issued. Figure 1−4 shows an example of an ACTV
command before an SDRAM write. In this example, t
cycles. The ACTV command for SDRAM reads are identical. Reads or writes
to the currently active row and bank of SDRAM can achieve much higher
throughput than reads or writes to random areas, because every time a new
page is accessed, the ACTV command must be issued.
ACTV
Bank Activate/Row Address
TRCD=3 cycles
Row Address
is incurred before
RCD
RCD
Write Write
BE1 BE2
CA1 CA2
D1 D2
= 3 EMIF clock
Write
BE3
CA3
D3
SPRU266A