MSM5718B70 View Datasheet(PDF) - Oki Electric Industry
Part Name
Description
MFG CO.
'MSM5718B70' PDF : 40 Pages View PDF
MSM5718B70
¡ Semiconductor
Since the RDRAM's internal clocks are disabled while in powerdown mode, refresh must be
maintained manually by the master device. This is done by supplying a low frequency square wave
on the SIn TTL signal. This propagates through each RDRAM and is used to initiate asynchronous
refresh operations in each device.
Each RDRAM may be placed in either low or high threshold powerdown mode. Threshold refers
to the number of serial mode packets required to wake up the RDRAM. A low threshold requires
relatively few serial mode packets while a high threshold requires a larger number. The actual power
dissipation is identical in both modes.
An example of where these modes are used is in a portable computer application, as shown below.
The sleep mode is implemented by placing a majority of the RDRAMs in high threshold powerdown
while the RDRAM that contains the frame buffer is placed in low threshold powerdown. This
permits screen refresh to take place without powering up the entire memory system.
Reset Mode
(place device in known state)
Count < tMODEAR,MIN
PowerOn
Standby Mode
(reduced power dissipation)
PowerDown Mode
(minimum power dissipation)
Count ≥ tMODEPA {1/0}, MIN
Count ≥ tMODEAR,MIN
Count = # SMode Packets
Count ≥ tMODESA, MIN
Count ≥ tMODEDELAY, MAX
Active Mode
(ready to receive request)
Transaction complete
BusCtrleven = 1
(Start Bit)
Write SetPD in MinInterval register
Transaction Processing States
Fig. 16 RDRAM Operating Modes
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