- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄97865 > DS1991L-F5 (DALLAS SEMICONDUCTOR) SPECIALTY MEMORY CIRCUIT, MEDB2 PDF資料下載
參數(shù)資料
| 型號： | DS1991L-F5 |
| 廠商： | DALLAS SEMICONDUCTOR |
| 元件分類： | Memory IC:Other |
| 英文描述： | SPECIALTY MEMORY CIRCUIT, MEDB2 |
| 封裝： | MICROCAN-2 |
| 文件頁數(shù)： | 14/14頁 |
| 文件大?。?/td> | 281K |
| 代理商： | DS1991L-F5 |
DS1991
9 of 14
TRANSACTION SEQUENCE
The protocol for accessing the DS1991 via the 1-Wire port is as follows:
Initialization
ROM Function Command
Memory Function Command
Transaction/Data
INITIALIZATION
All transactions on the 1-Wire bus begin with an initialization sequence. The initialization sequence
consists of a reset pulse transmitted by the bus master followed by presence pulse(s) transmitted by the
slave(s). The presence pulse lets the bus master know that the DS1991 is on the bus and is ready to
operate. For more details, see the “1-Wire Signaling” section
ROM FUNCTION COMMANDS
Once the bus master has detected a presence pulse, it can issue one of the four ROM function commands.
All ROM function commands are 8 bits long. A list of these commands follows (refer to flowchart in
Figure 9).
Read ROM [33H]
This command allows the bus master to read the DS1991’s 8-bit family code, unique 48-bit serial number
and 8-bit CRC. This command can be used only if there is a single DS1991 on the bus. If more than one
slave is present on the bus, a data collision will occur when all slaves try to transmit at the same time
(open drain will produce a wired-AND result).
Match ROM [55H]
The match ROM command, followed by a 64-bit ROM sequence, allows the bus master to address a
specific DS1991 on a multidrop bus. Only the DS1991 that exactly matches the 64-bit ROM sequence
will respond to the subsequent memory function command. All slaves that do not match the 64-bit ROM
sequence will wait for a reset pulse. This command can be used with a single or multiple devices on the
bus.
Skip ROM [CCH]
This command can save time in a single drop bus system by allowing the bus master to access the
memory functions without providing the 64-bit ROM code. If more than one slave is present on the bus
and a read command is issued following the Skip ROM command, data collision will occur on the bus as
multiple slaves transmit simultaneously (open drain will produce a wired-AND result).
Search ROM [F0H]
When a system is initially brought up, the bus master might not know the number of devices on the 1-
Wire bus or their 64-bit ROM codes. The Search ROM command allows the bus master to use a process
of elimination to identify the 64-bit ROM codes of all slave devices on the bus. The ROM search process
is the repetition of a simple 3-step routine: read a bit, read the complement of the bit, then write the
desired value of that bit. The bus master performs this simple 3-step routine on each bit of the ROM.
After one complete pass, the bus master knows the contents of the ROM in one device. The remaining
number of devices and their ROM codes may be identified by additional passes. See Chapter 5 of the
Book of DS19xx iButton Standards for a comprehensive discussion of a search ROM, including an actual
example.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| DS1994L-F5 | SPECIALTY MEMORY CIRCUIT, MRDB2 |
| DS1993L-F5 | SPECIALTY MEMORY CIRCUIT, MRDB2 |
| DS1992L-F5 | SPECIALTY MEMORY CIRCUIT, MRDB2 |
| DS1996L-F5 | SPECIALTY MEMORY CIRCUIT, MADB2 |
| DS2016 | 2K X 8 STANDARD SRAM, 100 ns, PDIP24 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1991L-F5/A1A | 功能描述:iButton RoHS:否 存儲類型:SRAM 存儲容量:512 B 組織: 工作電源電壓:3 V to 5.25 V 接口類型:1-Wire 最大工作溫度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封裝 / 箱體:F5 MicroCan 制造商:Maxim Integrated |
| DS1991L-F5+ | 功能描述:iButton RoHS:否 存儲類型:SRAM 存儲容量:512 B 組織: 工作電源電壓:3 V to 5.25 V 接口類型:1-Wire 最大工作溫度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封裝 / 箱體:F5 MicroCan 制造商:Maxim Integrated |
| DS1991L-F5+A1A | 功能描述:iButton RoHS:否 存儲類型:SRAM 存儲容量:512 B 組織: 工作電源電壓:3 V to 5.25 V 接口類型:1-Wire 最大工作溫度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封裝 / 箱體:F5 MicroCan 制造商:Maxim Integrated |
| DS1991L-F5W | 功能描述:iButton RoHS:否 存儲類型:SRAM 存儲容量:512 B 組織: 工作電源電壓:3 V to 5.25 V 接口類型:1-Wire 最大工作溫度:+ 85 C 尺寸:17.35 mm x 5.89 mm 封裝 / 箱體:F5 MicroCan 制造商:Maxim Integrated |
| DS1991LP | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。