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參數(shù)資料
| 型號(hào)： | FM25640 |
| 廠商： | Electronic Theatre Controls, Inc. |
| 英文描述： | TERM STRIP, TH, LO PRO |
| 中文描述： | 64Kb的FRAM的串行存儲(chǔ)器 |
| 文件頁數(shù)： | 6/14頁 |
| 文件大小： | 131K |
| 代理商： | FM25640 |
Ramtron
FM25640
Rev. 2.1
Aug 2003
6 of 14
RDSR - Read Status Register
The RDSR command allows the bus master to verify
the contents of the Status register. Reading Status
provides information about the current state of the
write protection features. Following the RDSR op-
code, the FM25640 will return one byte with the
contents of the Status register. The Status register is
described in detail in a later section.
WRSR – Write Status Register
The WRSR command allows the user to select
certain write protection features by writing a byte to
the Status register. Prior to issuing a WRSR
command, the /WP pin must be high or inactive.
Note that on the FM25640, /WP only prevents
writing to the Status register, not the memory array.
Prior to sending the WRSR command, the user must
send a WREN command to enable writes. Note that
executing a WRSR command is a write operation
and therefore clears the Write Enable Latch. The bus
configuration of RDSR and WRSR are shown
below.
Figure 7. RDSR Bus Configuration
Figure 8. WRSR Bus Configuration
Status Register & Write Protection
The write protection features of the FM25640 are
multi-tiered. First, a WREN op-code must be issued
prior to any write operation. Assuming that writes are
enabled using WREN, writes to memory are
controlled by the Status register. As described above,
writes to the status register are performed using the
WRSR command and subject to the /WP pin. The
Status register is organized as follows.
Table 2. Status Register
Bit
7
6
5
Name
WPEN
0
0
Bits 0 and 4-6 are fixed at 0 and can not be modified.
Note that the Ready bit in many EEPROMs is
unnecessary as the FRAM writes in real-time and is
never busy. The WPEN, BP1 and BP0 control write
protection features. They are nonvolatile! The WEL
flag indicates the state of the Write Enable Latch.
4
0
3
BP1
2
BP0
1
WEL
0
0
Writing the WEL bit in the status register has no
effect.
BP1 and BP0 are memory block write protection
bits. They specify portions of memory that are write
protected as shown in the following table.
Table 3. Block Memory Write Protection
BP1
BP0
Protected Address Range
0
0
None
0
1
1800h to 1FFFh (upper )
1
0
1000h to 1FFFh (upper )
1
1
0000h to 1FFFh (all)
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| FM25640-S | LOW PROFILE .025 SQ STRIPS |
| FM25CL04 | 4Kb FRAM Serial 3V Memory |
| FM25CL04-S | 4Kb FRAM Serial 3V Memory |
| FM25CL64 | 4Kb FRAM Serial 3V Memory |
| FM25CL64-S | 4Kb FRAM Serial 3V Memory |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| FM25640_05 | 制造商:RAMTRON 制造商全稱:RAMTRON 功能描述:64Kb FRAM Serial Memory |
| FM25640_07 | 制造商:RAMTRON 制造商全稱:RAMTRON 功能描述:64Kb FRAM Serial Memory |
| FM25640B | 制造商:RAMTRON 制造商全稱:RAMTRON 功能描述:64Kb Serial 5V F-RAM Memory |
| FM25640B_13 | 制造商:CYPRESS 制造商全稱:Cypress Semiconductor 功能描述:64Kb Serial 5V F-RAM Memory |
| FM25640B-G | 功能描述:F-RAM 64Kb Serial SPI 5V FRAM RoHS:否 存儲(chǔ)容量:512 Kbit 組織:64 K x 8 接口:SPI 工作電源電壓:2 V to 3.6 V 工作溫度范圍:- 40 C to + 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube 制造商:Cypress Semiconductor |
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