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參數(shù)資料
| 型號(hào)： | DS2224Z |
| 英文描述： | EconoRAM |
| 中文描述： | EconoRAM |
| 文件頁(yè)數(shù)： | 2/10頁(yè) |
| 文件大小： | 102K |
| 代理商： | DS2224Z |
DS2223/DS2224
080598 2/10
OPERATION
All communications to and from the EconoRAM are
accomplished via a single interface lead. EconoRAM
data is read and written through the use of time slots. All
data is preceded by a command byte to specify the type
of transaction.
Once a specific transaction has been
initiated, either a read or a write, it must be com-
pleted for all memory locations before another
transaction can be started.
1–WIRE SIGNALLING
The EconoRAM requires strict protocols to insure data
integrity. The protocol consists of three types of signal-
ling on one line: Write 0 time slot, Write 1 time slot and
Read Data time slot. All these signals are initiated by the
host.
READ/WRITE TIME SLOTS
The definitions of write and read time slots are illustrated
in Figures 1 through 3. All time slots are initiated by the
host driving the data line low. The falling edge of the data
line synchronizes the EconoRAM to the host by trigger-
ing a delay circuit in the EconoRAM. During write time
slots, the delay circuit determines when the EconoRAM
will sample the data line. For a read data time slot, if a “0”
is to be transmitted, the delay circuit determines how
long the EconoRAM will hold the data line low overriding
the 1 generated by the host. If the data bit is a “1”, the
EconoRAM will leave the read data time slot
unchanged.
COMMAND BYTE
The command byte to specify the type of transaction is
transmitted LSB first from the host to the EconoRAM
using write time slots. The first bit of the command byte
(see Figure 4) is a logic 1. This indicates to the Econo-
RAM that a command byte is being written. The next two
bits are the select bits which denote the physical
address of the EconoRAM that is to be accessed (set to
00 currently). The remaining five bits determine whether
a read or a write operation is to follow. If a write operation
is to be performed, all five bits are set to a logic 1 level. If
a read operation is to be performed, any or all of these
bits are set to a logic 0 level. All eight bits of the com-
mand byte are transmitted to the EconoRAM with a sep-
arate time slot for each bit.
READ OR WRITE TRANSACTION
Read or write transactions are performed by initializing
the EconoRAM to a known state, issuing a command
byte, and then generating the time slots to either read
EconoRAM contents or write new data. Each transac-
tion consists of 264 time slots. Eight time slots transmit
the command byte, the remaining 256 time slots trans-
fer the data bits. (See Figure 5.) Once a transaction is
started, it must be completed before a new transaction
can begin.
To initially set the EconoRAM into a known state, 264
Write Zero time slots must be sent by the host. These
Write Zero time slots will not corrupt the data in the Eco-
noRAM since a command byte has not been written.
This operation will increment the address pointer inter-
nal to the EconoRAM to its maximum count value. Upon
reaching this maximum value, the EconoRAM will
ignore all additional Write Zero time slots issued to it and
the internal address pointer will remain locked at the top
count value. This condition is removed by the reception
of a Write One time slot, typically the first bit of a com-
mand byte.
Once the EconoRAM has been set into a known state,
the command byte is transmitted to the EconoRAM with
eight write time slots. This resets the address pointer
internal to the EconoRAM and prepares it for the
appropriate operation, either a read or a write.
After the command byte has been received by the Eco-
noRAM, the host controls the transfer of data. In the
case of a read transaction, the host issues 256 read time
slots. In the case of a write transaction, the host issues
256 write time slots according to the data to be written.
All data is read and written least significant bit first.
Although the DS2224 has the first 32 bits replaced by
lasered ROM rather than SRAM, it requires 256 write
time slots for a complete write transaction. The data
being sent during the first 32 write time slots has no
effect on the DS2224 other than advancing the internal
address pointer. As stated previously, it is not possible
to change from read to write or vice versa before a trans-
action is completed.
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| DS2229-120 | x16 SRAM Module |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS2224Z+T&R | 功能描述:靜態(tài)隨機(jī)存取存儲(chǔ)器 RoHS:否 制造商:Cypress Semiconductor 存儲(chǔ)容量:16 Mbit 組織:1 M x 16 訪問(wèn)時(shí)間:55 ns 電源電壓-最大:3.6 V 電源電壓-最小:2.2 V 最大工作電流:22 uA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSOP-48 封裝:Tray |
| DS2227 | 制造商:DALLAS 制造商全稱(chēng):Dallas Semiconductor 功能描述:Flexible NV SRAM Stik |
| DS2227-070 | 功能描述:IC NVSRAM 4MBIT 70NS 72SIMM RoHS:否 類(lèi)別:集成電路 (IC) >> 存儲(chǔ)器 系列:- 標(biāo)準(zhǔn)包裝:150 系列:- 格式 - 存儲(chǔ)器:EEPROMs - 串行 存儲(chǔ)器類(lèi)型:EEPROM 存儲(chǔ)容量:4K (2 x 256 x 8) 速度:400kHz 接口:I²C，2 線串口 電源電壓:2.5 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 封裝/外殼:8-VFDFN 裸露焊盤(pán) 供應(yīng)商設(shè)備封裝:8-DFN（2x3） 包裝:管件 產(chǎn)品目錄頁(yè)面:1445 (CN2011-ZH PDF) |
| DS2227-100 | 功能描述:IC NVSRAM 4MBIT 100NS 72SIMM RoHS:否 類(lèi)別:集成電路 (IC) >> 存儲(chǔ)器 系列:- 標(biāo)準(zhǔn)包裝:150 系列:- 格式 - 存儲(chǔ)器:EEPROMs - 串行 存儲(chǔ)器類(lèi)型:EEPROM 存儲(chǔ)容量:4K (2 x 256 x 8) 速度:400kHz 接口:I²C，2 線串口 電源電壓:2.5 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 封裝/外殼:8-VFDFN 裸露焊盤(pán) 供應(yīng)商設(shè)備封裝:8-DFN（2x3） 包裝:管件 產(chǎn)品目錄頁(yè)面:1445 (CN2011-ZH PDF) |
| DS2227-120 | 功能描述:IC NVSRAM 4MBIT 120NS 72SIMM RoHS:否 類(lèi)別:集成電路 (IC) >> 存儲(chǔ)器 系列:- 標(biāo)準(zhǔn)包裝:150 系列:- 格式 - 存儲(chǔ)器:EEPROMs - 串行 存儲(chǔ)器類(lèi)型:EEPROM 存儲(chǔ)容量:4K (2 x 256 x 8) 速度:400kHz 接口:I²C，2 線串口 電源電壓:2.5 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 封裝/外殼:8-VFDFN 裸露焊盤(pán) 供應(yīng)商設(shè)備封裝:8-DFN（2x3） 包裝:管件 產(chǎn)品目錄頁(yè)面:1445 (CN2011-ZH PDF) |
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