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ADSP-SC58x DMC Register Descriptions
Timing 1 Register
The
register selects timing parameters for DMC operation to corresponding with parameters of the
DMC_TR1
SDRAM device that is used in the system. The timing registers must be programmed to match the device for correct
operation of the SDRAM and must be programmed before initializing the SDRAM. Note that all values for bit
fields in
DMC_TR1
are in increments of clock cycle time (t
TREF (R/W)
Timing Refresh Interval
TRRD (R/W)
Timing Read-Read Delay
Figure 10-26: DMC_TR1 Register Diagram
Table 10-35: DMC_TR1 Register Fields
Bit No.
(Access)
30:28
TRRD
(R/W)
23:16
TRFC
(R/W)
13:0
TREF
(R/W)
10–66
15
14
13
12
11
10
9
8
0
0
0
0
0
0
0
0
31
30
29
28
27
26
25
24
0
0
0
0
0
0
0
0
Bit Name
Timing Read-Read Delay.
The DMC_TR1.TRRD field selects the active-to-active time (t
mum number of clock cycles occurring from a bank x active command to a bank y
active command.
Timing Refresh-to-Command.
The DMC_TR1.TRFC field selects the refresh-to-active command delay (t
is the number of clock cycles required for the SDRAM to recover from a refresh signal
to be ready to take the next command. It is also the number of clock cycles needed for
the SDRAM to recover from executing one active command and ready to accept the
next active command.
Timing Refresh Interval.
The DMC_TR1.TREF field selects the refresh interval time (t
ber of clock cycles occurring from one refresh command to the next refresh command.
The actual timing of issuing a precharge command may be delayed by if the SDRAM
is processing a normal access. However, the delay is not accumulative so there is no
need to shorten the refresh interval to account for the memory access time. The non-
accumulative refresh delay typically increases memory bandwidth by a few percentage
points.
ADSP-SC58x/ADSP-2158x SHARC+ Processor Hardware Reference
).
CK
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
23
22
21
20
19
18
17
16
0
0
0
0
0
0
0
0
Description/Enumeration
TRFC (R/W)
Timing Refresh-to-Command
), which is the mini-
RRD
), which is the num-
REF
), which
RFC
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