 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
IS66WVE1M16EALL-70BLI Datasheet(PDF) 14 Page - Integrated Silicon Solution, Inc |
|
||||||||||||||||||||||||||||||
IS66WVE1M16EALL-70BLI Datasheet(HTML) 14 Page - Integrated Silicon Solution, Inc |
|
|
14 / 34 page 
14 IS66/67WVE1M16EALL/EBLL/ECLL IS66/67WVE1M16TALL/TBLL/TCLL Rev. C | Oct. 2015 www.issi.com - SRAM@issi.com Software Access Sequence The contents of the CR can be read or modified using a software access sequence. The nature of this access mechanism can potentially eliminate the need for the ZZ# ball. If the software-access mechanism is used, ZZ# can simply be tied to VDDQ; the port line typically used for ZZ# control purposes will no longer be required. However, ZZ# should not be tied to VDDQ if the system will use DPD; DPD cannot be enabled or disabled using the software-access sequence. The CR is loaded using a four-step sequence consisting of two READ operations followed by two WRITE operations (see Figure 6). The READ sequence is virtually identical except that an asynchronous READ is performed during the fourth operation (see Figure 7). The address used during all READ and WRITE operations is the highest address of the PSRAM device being accessed (FFFFFh); the content of this address is not changed by using the software-access sequence. The data bus is used to transfer data into or out of bit[15:0] of the CR. Writing to the CR using the software-access sequence modifies the function of the ZZ# ball. After the software sequence loads the CR, the level of the ZZ# ball no longer enables PAR operation. PAR operation is updated whenever the software-access sequence loads a new value into the CR. This ZZ# functionality will remain active until the next time the device is powered up. The operation of the ZZ# ball is not affected if the software-access sequence is only used to read the contents of the CR. Use of the software-access sequence does not affect the performance of standard (ZZ#-controlled) CR loading. Figure 6 : Configuration Register Write Notes : 1. CR : 0000h MAX ADDRESS OUTPUT DATA MAX ADDRESS OUTPUT DATA MAX ADDRESS MAX ADDRESS CR VALUE IN *Note1 OE# Address DQ0- DQ15 CE# UB#/LB# WE# Read Read Write Write |
|
English ▼
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
