MSC8156 Freescale Semiconductor, Inc, MSC8156 Datasheet - Page 36

• Manufacturer Part Number: MSC8156
• Description: Six-core Digital Signal Processor
• Manufacturer: Freescale Semiconductor, Inc

Electrical Characteristics
2.6
This section describes the AC timing characteristics for the MSC8156.
2.6.1
This section describes the AC electrical characteristics for the DDR SDRAM interface.
2.6.1.1
Table 18
Table 19
Table 20
36
Controller Skew for MDQS—MDQ/MECC/MDM
• 800 MHz data rate
• 667 MHz data rate
Tolerated Skew for MDQS—MDQ/MECC/MDM
• 800 MHz data rate
• 667 MHz data rate
Notes:
AC input low voltage
AC input high voltage
Note:
AC input low voltage
AC input high voltage
Note:
provides the input AC timing specifications for the DDR SDRAM when
provides the input AC timing specifications for the DDR SDRAM when
provides the input AC timing specifications for the DDR SDRAM interface.
1.
2.
3.
At recommended operating conditions with V
At recommended operating conditions with V
AC Timing Characteristics
DDR SDRAM AC Timing Specifications
t
captured with MDQS[n]. Subtract this value from the total timing budget.
At recommended operating conditions with V
The amount of skew that can be tolerated from MDQS to a corresponding MDQ signal is called t
determined by the following equation: t
absolute value of t
CISKEW
DDR SDRAM Input AC Timing Specifications
Table 18. DDR2 SDRAM Input AC Timing Specifications for 1.8 V Interface
Table 19. DDR3 SDRAM Input AC Timing Specifications for 1.5 V Interface
represents the total amount of skew consumed by the controller between MDQS[n] and any corresponding bit that is
Parameter
Parameter
Parameter
MSC8156 Six-Core Digital Signal Processor Data Sheet, Rev. 1
CISKEW
Table 20. DDR SDRAM Input AC Timing Specifications
.
DISKEW
DDDDR
DDDDR
DDDDR
= ±(T ÷ 4 – abs(t
of 1.8 ± 5%.
of 1.5 ± 5%.
(1.8 V or 1.5 V) ± 5%
Symbol
t
t
CISKEW
DISKEW
CISKEW
Symbol
Symbol
V
V
V
V
IH
IH
IL
IL
)) where T is the clock period and abs(t
V
V
–200
–240
–425
–510
MV
DDDDR
DDDDR
Min
MV
REF
REF
Min
Min
—
—
+ 0.175
+ 0.20
(typ) = 1.8 V.
(typ) = 1.5 V.
Max
200
240
425
510
DISKEW
Freescale Semiconductor
MV
MV
REF
REF
.This can be
Max
Max
—
—
– 0.175
– 0.20
Unit
ps
ps
ps
ps
CISKEW
) is the
Notes
Unit
Unit
1, 2
2, 3
V
V
V
V