参数资料
型号: DS2432X
厂商: MAXIM INTEGRATED PRODUCTS INC
元件分类: Programmable ROM
英文描述: 1K X 1 1-WIRE SERIAL EEPROM, PBGA6
封装: UCSP-8
文件页数: 14/16页
文件大小: 168K
代理商: DS2432X
Abridged Data Sheet
DS2432
7 of 14
ROM FUNCTION COMMANDS
Once the bus master has detected a presence, it can issue one of the seven ROM function commands that
the DS2432 supports. All ROM function commands are eight 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 DS2432’s 8-bit family code, unique 48-bit serial
number, and 8-bit CRC. This command should only be used if there is a single slave 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). The resultant family code and 48-bit serial number
read by the master will be invalid.
Match ROM [55h]
The match ROM command, followed by a 64-bit registration number, allows the bus master to address a
specific DS2432 on a multidrop bus. Only the DS2432 that exactly matches the 64-bit registration
number will respond to the following memory function command. All other slaves will wait for a reset
pulse. This command can be used with a single or multiple devices on the bus.
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 registration numbers. The search ROM command allows the bus master to use
a process of elimination to identify the 64-bit numbers of all slave devices on the bus. The search ROM
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 3-step routine on each bit of the registration
number. After one complete pass, the bus master knows the 64-bit number of one device. Additional
passes will identify the registration numbers of the remaining devices. See Chapter 5 of the Book of
DS19xx iButton Standards for a detailed discussion of a search ROM, including an actual example.
Skip ROM [CCh]
This command can save time in a single drop bus system by allowing the bus master to access the
memory and SHA functions without providing the 64-bit registration number. If more than one slave is
present on the bus and, for example, a read command is issued following the Skip ROM command, data
collision will occur on the bus as multiple slaves transmit simultaneously (open drain pull-downs will
produce a wired-AND result).
Overdrive Skip ROM [3Ch]
On a single-drop bus this command can save time by allowing the bus master to access the memory and
SHA functions without providing the 64-bit registration number. Unlike the normal Skip ROM command
the Overdrive Skip ROM sets the DS2432 in the Overdrive Mode (OD = 1). All communication
following this command code has to occur at Overdrive Speed until a reset pulse of minimum 480 s
duration resets all devices on the bus to regular speed (OD = 0).
When issued on a multidrop bus this command will set all Overdrive-supporting devices into Overdrive
mode. To subsequently address a specific Overdrive-supporting device, a reset pulse at Overdrive speed
has to be issued followed by a Match ROM or Search ROM command sequence. This will speed up the
search process. If more than one Overdrive-supporting slave is present on the bus and the Overdrive Skip
ROM command is followed by a read command, data collision will occur on the bus as multiple slaves
transmit simultaneously (open drain pull-downs will produce a wired-AND result).
相关PDF资料
PDF描述
DS2432P 1K X 1 1-WIRE SERIAL EEPROM, PDSO6
DS2433 512 X 8 1-WIRE SERIAL EEPROM, PBCY3
DS2433X 4K X 1 1-WIRE SERIAL EEPROM, UUC2
DS2433S 512 X 8 1-WIRE SERIAL EEPROM, PDSO8
DS2434S SPECIALTY MEMORY CIRCUIT, PDSO16
相关代理商/技术参数
参数描述
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DS2432X+U 制造商:Maxim Integrated Products 功能描述:1-W EEPROM 1KB W/SHA-1 UCSP PARTIAL - Rail/Tube
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DS2432X-S 功能描述:电可擦除可编程只读存储器 RoHS:否 制造商:Atmel 存储容量:2 Kbit 组织:256 B x 8 数据保留:100 yr 最大时钟频率:1000 KHz 最大工作电流:6 uA 工作电源电压:1.7 V to 5.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8
DS2432X-S+ 制造商:Maxim Integrated Products 功能描述:1-W EEPROM 1KB W/SHA-1 UCSP 2.5K TR - Tape and Reel