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零件编号 | IZ1990 | ||
描述 | CMOS IC FOR ELECTRONIC KEY | ||
制造商 | Integral | ||
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IZ1990
CMOS IC FOR ELECTRONIC KEY
DESCRIPTION
CMOS microcircuit is essentially an electronic carrier of the unique 64-bit digital code. The code
is stored in the internal nonvolatile memory. The data exchange is performed by the protocol 1-
Wire, which requires one sole data pin and the common pin. The microcircuit supports the
function of the protocol 1-Wire of ROM search, which makes it possible for several devices to
operate on one bus. This protocol determines the alteration conditions of the bus status and the
time intervals during synchronization by the synchropulses cuts of the control device. Data read-
out and writing are performed by the junior significant bit forward.
TRANSACTION SEQUENCE
Access sequence to IZ1990 via 1-Wire port is as follows:
Initialization
ROM function command
Data read-out
INITIALIZATION
All transactions on the bus 1-Wire start with the initialization sequence. The initialization
sequence consists of the reset pulse, applied by the bus master, followed by the availability
pulse (or pulses), applied by the slave buses (or slave buses).
The availability pulse informs the bus master, that IZ1990 is connected to the bus and is ready
for operation.
ROM FUNCTIONS COMMANDS
After the bus master has determined availability of the device, it can apply one out of four
commands for operation with ROM. All commands for operation with ROM have the length of 8
bits. These commands are enumerated below (see also the diagram in Fig. 4)
ROM Reading [33h] or [0Fh]
This command enables thwe bus master to read the 8-bit group code IZ1990, its unique 48-bit
serial number and 8-bit control total (CRC). This command can be used only, if the bus has one
device IZ1990. If the bus has more, than one slave, there will be a conflict of data, when all
slave ones, when all slave ones attempt to apply at the same time (the open drains will apply the
mount AND). In IZ1990 the function ROM Reading may work with the command byte 33h or
0Fh, which ensures compatibility with the devices DS1990, which will respond only to the
command word 0Fh.
Comparison of ROM [55h] / ROM Skipping [CCh]
As the device IZ1990 contains only 64-bit ROM, the commands COMPARISON OF ROM and
ROM SKIPPING from Protocol 1-Wire are not applied and do not case the response on the bus,
if applied by the master.
Search of ROM [F0h]
When the system is started initially, the bus master may not know the numbers of the devices,
connected to the bus 1-Wire or their 64-bit ROM codes. The ROM search command enables the
bus master to use the exception process, in order to determine the 64-bit ROM codes of all
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页数 | 7 页 | ||
下载 | [ IZ1990.PDF 数据手册 ] |
零件编号 | 描述 | 制造商 |
IZ1990 | CMOS IC | IK Semiconductor |
IZ1990 | CMOS IC FOR ELECTRONIC KEY | Integral |
IZ1991 | CIRCUIT OF MULTIFUNCTIONAL ELECTRONIC KEY | Integral |
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