SDRAM Interface
9-38
9.4.8.2
TMS320C6211/C6711 SDRAM Read
Figure 9–25 shows the ’C6211/C6711 performing a three word read burst from
SDRAM. The ’C6211/C6711 uses a burst length of four, and has a program-
mable CAS latency of either two or three cycles. The CAS latency is three cycles
in this example (CASL = 1). Since the default burst length is four words, the
SDRAM returns four pieces of data for every read command. If no additional ac-
cess are pending to the EMIF, as in Figure 9–25, the read burst completes and
the unneeded data is disregarded. If accesses are pending, the read burst can
be interrupted with a new command (READ,WRT,DEAC,DCAB), controlled by
the SDRAM extension register. If a new access is not pending, the DCAB/DEAC
command is not performed until the page information becomes invalid.
Figure 9–25. TMS320C6211 SDRAM Read
EA[11:2]
Column
SDWE
SDRAS
ED[31:0]
EA12
SDCAS
ÁÁ
ÁÁ
Á
Á
D4
D3
D2
D1
EA[21:13]
BE[3:0]
Bank
BE4
BE3
BE2
BE1
D4
ignored
latched
D3
latched
D2
latched
D1
Read
CEx
ECLKOUT
CAS latency = 3