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STK14C88-N35 参数 Datasheet PDF下载

STK14C88-N35图片预览
型号: STK14C88-N35
PDF下载: 下载PDF文件 查看货源
内容描述: [Non-Volatile SRAM, 32KX8, 35ns, CMOS, PDSO32, 0.300 INCH, PLASTIC, SOIC-32]
分类和应用: 可编程只读存储器电动程控只读存储器电可擦编程只读存储器静态存储器光电二极管内存集成电路
文件页数/大小: 12 页 / 120 K
品牌: SIMTEK [ SIMTEK CORPORATION ]
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STK14C88  
Figure 2 shows the proper connection of capacitors  
for automatic store operation. A charge storage  
capacitor having a capacity of between 68µF and  
220µF (± 20%) rated at 6V should be provided.  
SOFTWARE NONVOLATILE RECALL  
A software RECALL cycle is initiated with a sequence  
of READ operations in a manner similar to the soft-  
ware STORE initiation. To initiate the RECALL cycle,  
the following sequence of E controlled READ opera-  
tions must be performed:  
In system power mode (Figure 3), both VCCX and  
VCAP are connected to the + 5V power supply without  
the 68µF capacitor. In this mode the AutoStore™  
function of the STK14C88 will operate on the stored  
system charge as power goes down. The user must,  
however, guarantee that VCCX does not drop below  
3.6V during the 10ms STORE cycle.  
1. Read address  
2. Read address  
3. Read address  
4. Read address  
5. Read address  
6. Read address  
0E38 (hex)  
31C7 (hex)  
03E0 (hex)  
3C1F (hex)  
303F (hex)  
0C63 (hex)  
Valid READ  
Valid READ  
Valid READ  
Valid READ  
Valid READ  
Initiate RECALL cycle  
If an automatic STORE on power loss is not required,  
then VCCX can be tied to ground and + 5V applied to  
VCAP (Figure 4). This is the AutoStoreInhibit  
mode, in which the AutoStorefunction is disabled.  
If the STK14C88 is operated in this configuration,  
references to VCCX should be changed to VCAP  
throughout this data sheet. In this mode, STORE  
operations may be triggered through software con-  
trol or the HSB pin. It is not permissable to change  
between these three options on the fly.  
Internally, RECALL is a two-step procedure. First, the  
SRAM data is cleared, and second, the nonvolatile  
information is transferred into the SRAM cells. After  
the tRECALL cycle time the SRAM will once again be  
ready for READ and WRITE operations. The RECALL  
operation in no way alters the data in the EEPROM  
cells. The nonvolatile data can be recalled an unlim-  
ited number of times.  
AutoStoreOPERATION  
In order to prevent unneeded STORE operations,  
automatic STOREs as well as those initiated by  
externally driving HSB low will be ignored unless at  
least one WRITE operation has taken place since the  
most recent STORE or RECALL cycle. Software-  
initiated STORE cycles are performed regardless of  
whether a WRITE operation has taken place. An  
optional pull-up resistor is shown connected to HSB.  
This can be used to signal the system that the  
AutoStorecycle is in progress.  
The STK14C88 can be powered in one of three  
modes.  
During normal AutoStoreoperation, the  
STK14C88 will draw current from VCCX to charge a  
capacitor connected to the VCAP pin. This stored  
charge will be used by the chip to perform a single  
STORE operation. After power up, when the voltage  
on the VCAP pin drops below VSWITCH, the part will  
automatically disconnect the VCAP pin from VCCX and  
initiate a STORE operation.  
10kΩ  
1
32  
31  
30  
1
32  
31  
30  
1
32  
31  
30  
+
16  
17  
16  
17  
16  
17  
Figure 2: AutoStoreMode  
Figure 3: System Power Mode  
Figure 4: AutoStore™  
Inhibit Mode  
*If HSB is not used, it should be left unconnected.  
July 1999  
5-29