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datasheet gDDR3 SDRAM
Rev. 1.1
K4W1G1646G
[ Table 63 ] Burst Type and Burst Order
NOTE :
1. In case of burst length being fixed to 4 by MR0 setting, the internal write operation starts two clock cycles earlier than for the BL8 mode. This means that the starting point for
tWR and tWTR will be pulled in by two clocks. In case of burst length being selected on-the-fly via A12/BC, the internal write operation starts at the same point in time like a
burst of 8 write operation. This means that during on-the-fly control, the starting point for tWR and tWTR will not be pulled in by two clocks.
2. 0...7 bit number is value of CA[2:0] that causes this bit to be the first read during a burst.
3. T: Output driver for data and strobes are in high impedance.
4. V: a valid logic level (0 or 1), but respective buffer input ignores level on input pins.
5. X: Don’t Care.
16.4.2.2 CAS Latency
The CAS Latency is defined by MR0(bits A4-A6) as shown in Figure 34. CAS Latency is the delay, in clock cycles, between the internal Read command
and the availability of the first bit of output data. gDDR3 SDRAM does not support any half clock latencies. The overall Read Latency (RL) is defined as
Additive Latency (AL) + CAS Latency (CL); RL = AL + CL. For more information on the supported CL and AL settings based on the operating clock fre-
quency, refer to " Standard Speed Bins" on each component datasheet. For detailed Read operation refer to "READ Operation" on page 92
16.4.2.3 Test Mode
The normal operating mode is selected by MR0(bit A7 = 0) and all other bits set to the desired values shown in Figure 34. Programming bit A7 to a ’1’
places the gDDR3 SDRAM into a test mode that is only used by the DRAM Manufacturer and should NOT be used. No operations or functionality is guar-
anteed if A7 = 1.
16.4.2.4 DLL Reset
The DLL Reset bit is self-clearing, meaning it returns back to the value of ’0’ after the DLL reset function has been issued. Once the DLL is enabled, a
subsequent DLL Reset should be applied. Any time the DLL reset function is used, tDLLK must be met before any functions that require the DLL can be
used (i.e. Read commands or ODT synchronous operations).
16.4.2.5 Write Recovery
The programmed WR value MR0(bits A9, A10, and A11) is used for the auto precharge feature along with tRP to determine tDAL WR(write recovery for
auto-precharge)min in clock cycles is calculated by dividing tWR(in ns) by tCK(in ns) and rounding up to the next integer: WRmin[cycles] =
Roundup(tWR[ns]/tCK[ns]). The WR must be programmed to be equal or larger than tWR(min).
16.4.2.6 Precharge PD DLL
MR0 (bit A12) is used to select the DLL usage during precharge power-down mode. When MR0(A12 = 0), or "slow-exit", the DLL is frozen after entering
precharge power-down (for potential power savings) and upon exit requires tXPDLL to be met prior to the next valid command. When MR0(A12 = 1), or
"fast-exit", the DLL is maintained after entering precharge power-down and upon exiting power-down requires tXP to be met prior to the next valid com-
mand.
Burst
Length
READ/
WRITE
Starting
Column
ADDRESS
(A2,A1,A0)
burst type = Sequential
(decimal)
A3 = 0
burst type = Interleaved
(decimal)
A3 = 1
Notes
4
Chop
READ
0 0 0 0,1,2,3,T,T,T,T 0,1,2,3,T,T,T,T 1, 2, 3
0 0 1 1,2,3,0,T,T,T,T 1,0,3,2,T,T,T,T 1, 2, 3
0 1 0 2,3,0,1,T,T,T,T 2,3,0,1,T,T,T,T 1, 2, 3
0 1 1 3,0,1,2,T,T,T,T 3,2,1,0,T,T,T,T 1, 2, 3
1 0 0 4,5,6,7,T,T,T,T 4,5,6,7,T,T,T,T 1, 2, 3
1 0 1 5,6,7,4,T,T,T,T 5,4,7,6,T,T,T,T 1, 2, 3
1 1 0 6,7,4,5,T,T,T,T 6,7,4,5,T,T,T,T 1, 2, 3
1 1 1 7,4,5,6,T,T,T,T 7,6,5,4,T,T,T,T 1, 2, 3
WRITE 0,V,V 0,1,2,3,X,X,X,X 0,1,2,3,X,X,X,X 1, 2, 4, 5
1,V,V 4,5,6,7,X,X,X,X 4,5,6,7,X,X,X,X 1, 2, 4, 5
8READ
0 0 0 0,1,2,3,4,5,6,7 0,1,2,3,4,5,6,7 2
0 0 1 1,2,3,0,5,6,7,4 1,0,3,2,5,4,7,6 2
0 1 0 2,3,0,1,6,7,4,5 2,3,0,1,6,7,4,5 2
0 1 1 3,0,1,2,7,4,5,6 3,2,1,0,7,6,5,4 2
1 0 0 4,5,6,7,0,1,2,3 4,5,6,7,0,1,2,3 2
1 0 1 5,6,7,4,1,2,3,0 5,4,7,6,1,0,3,2 2
1 1 0 6,7,4,5,2,3,0,1 6,7,4,5,2,3,0,1 2
1 1 1 7,4,5,6,3,0,1,2 7,6,5,4,3,2,1,0 2
WRITE V,V,V 0,1,2,3,4,5,6,7 0,1,2,3,4,5,6,7 2, 4