Memory Controller Programming Model
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
12-35
TIMING_CFG_3 sets the extended refresh recovery time, which is combined with
TIMING_CFG_1[REFREC] to determine the full refresh recovery time.
12.7.4
DDR SDRAM Timing Configuration Register 0 (TIMING_CFG_0)
TIMING_CFG_0 sets the number of clock cycles between various SDRAM control commands.
Table 12-18. TIMING_CFG_3 Bit Descriptions
Bits
Reset Description
Setting
—
31–19
0
Reserved. Write to zero for future compatibility.
REFR
18–16
0
Extended Refresh Recovery Time (t
RFC
)
Controls the number of clock cycles from a refresh command until
an activate command is allowed. This field is concatenated with
TIMING_CFG_1[REFREC] to obtain a 7-bit value for the total
refresh recovery. Note that hardware adds an additional 8 clock
cycles to the final 7-bit value of the refresh recovery.
t
RFC
= {TIMING_CFG_3 || REFREC} + 8
min. value = 8 clocks TIMING_CFG_3 = 0x0, REFREC = 0x0
max. value = 135 clocks TIMING_CFG_3 = 0x7, REFREC = 0xF =
112+15+8
000
0 clock cycles.
001
16 clock cycles.
010
32 clock cycles.
011
48 clock cycles.
100
64 clock cycles.
101
80 clock cycles.
110
96 clock cycles.
111
112 clock cycles.
—
15–0
0
Reserved. Write to zero for future compatibility.
TIMING_CFG_0
DDR SDRAM Timing Configuration Register 0
Offset 0x0104
Bit
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RWT
WRT
RRT
WWT
—
ACT_PD_EXIT
—
PRE_PD_EXIT
Type
R/W
R
R/W
R
R/W
Reset
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
1
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
—
PDT_PD_EXIT
—
MRS_CYC
Type
R
R/W
R
R/W
Reset
0
0
0
0
0
0
0
1
0
0
0
0
0
1
0
1
Table 12-19. TIMING_CFG_0 Field Descriptions
Bit Reset
Description
Settings
RWT
31–30
0
Read-to-Write Turn-Around (t
RTW
)
Specifies how many extra cycles to add between a read-to-write
turn-around. For 0 clock cycles, the DDR controller uses a fixed
number based on the
CAS
latency and write latency. A value
other than 0 adds extra cycles to this default calculation. By
default, the DDR controller determines the read-to-write
turn-around as CL – WL + BL/2 + 2. CL is the
CAS
latency
rounded up to the next integer, WL is the programmed write
latency, and BL is the burst length. (BL = 4 for all accesses)
00 0 clock cycles.
01 1 clock cycle.
10 2 clock cycles.
11 3 clock cycles.
Summary of Contents for MSC8144E
Page 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Page 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
Page 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Page 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Page 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Page 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Page 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Page 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
Page 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...