參數(shù)資料
型號: PPC440GRx-SpAfffTs
廠商: Applied Micro Circuits Corp.
英文描述: PowerPC 440GRx Embedded Processor
中文描述: 嵌入式處理器的PowerPC 440GRx
文件頁數(shù): 85/88頁
文件大?。?/td> 603K
代理商: PPC440GRX-SPAFFFTS
440GRx – PPC440GRx Embedded Processor
Revision 1.08 – October 15, 2007
Preliminary Data Sheet
AMCC Proprietary
85
Table 27. I/O Timing—DDR SDRAM T
SD
and T
HD
Notes:
1. T
SD
and T
HD
are measured under worst case conditions.
2. Clock speed for the values in the table is 166MHz.
3. The time values in the table include 1/4 of a cycle at 166MHz (6ns x 0.25 = 1.5 ns).
4. To obtain adjusted T
SD
and T
HD
values for lower clock frequencies, subtract 1.5 ns from the values in the table and add 1/4
of the cycle time for the lower clock frequency (for example, T
SD
1.5 + 0.25T
CYC
).
DDR SDRAM Read Operation
The read data capture logic is responsible for capturing the data outputs from the SDRAM devices and passing the
data back to the system clock domain. The data strobe signal (DQS) signals used to capture data are delayed to
ensure that the rising and falling edges of these strobes are in the middle of the valid window of data.
DDR devices send a DQS coincident with the read data so that the data can be reliably captured by the
PPC440GRx. The edges of these strobe signals are aligned with the data output by the SDRAM devices.
I
n order to reliably latch the data into a synchronizing FIFO, the PPC440GRx produces an internal, delayed version
of DQS. The amount of delay is user programmable. In the example shown in
Figure 12, DDR SDRAM DQS Read
Timing
, the delay is set to approximately 25% of the system clock. A delay compensation circuit in the PPC440GRx
keeps this delay constant.
Figure 12. DDR SDRAM DQS Read Timing
Signal Names
Reference Signal
DQS0
DQS1
DQS2
DQS3
DQS4
DQS5
DQS6
DQS7
DQS8
T
SD
(ns)
1.37
1.41
1.40
1.41
1.45
1.40
1.46
1.45
1.46
T
HD
(ns)
1.23
1.18
1.17
1.20
1.18
1.18
1.17
1.10
1.18
MemData00:07, DM0
MemData08:15, DM1
MemData16:23, DM2
MemData24:31, DM3
MemData32:39, DM4
MemData40:47, DM5
MemData48:55, DM6
MemData56:63, DM7
ECC0:7, DM8
DQS delay
MemClkOut
DQS
MemData
Delayed DQS
(data strobe)
相關PDF資料
PDF描述
PPC440GX-3RF800CZ Power PC 440GX Embedded Processor
PPC440GX-3CC533S Power PC 440GX Embedded Processor
PPC440GX-3CC667S Power PC 440GX Embedded Processor
PPC440GX-3CF400C Power PC 440GX Embedded Processor
PPC440GX-3CF533C Power PC 440GX Embedded Processor
相關代理商/技術參數(shù)
參數(shù)描述
PPC440GRX-STA400E 制造商:AppliedMicro 功能描述:32 BIT POWERPC CORE, UP TO 667 MHZ, 2 10/100/1000 ETHERNET, - Trays
PPC440GRX-STA533E 制造商:AppliedMicro 功能描述:32 BIT POWERPC CORE, UP TO 667 MHZ, 2 10/100/1000 ETHERNET, - Trays
PPC440GRX-STA533EZ 制造商:AppliedMicro 功能描述:32 BIT POWERPC CORE, UP TO 667 MHZ, 2 10/100/1000 ETHERNET, - Tape and Reel
PPC440GRX-STA667E 制造商:AppliedMicro 功能描述:32 BIT POWERPC CORE, UP TO 667 MHZ, 2 10/100/1000 ETHERNET, - Trays
PPC440GRX-SUA400E 制造商:AppliedMicro 功能描述:32 BIT POWERPC CORE, UP TO 667 MHZ, 2 10/100/1000 ETHERNET, - Trays