DS2490Y Maxim Integrated Products, DS2490Y Datasheet - Page 26

• Manufacturer Part Number: DS2490Y
• Description: IC BRIDGE CLIP USB TO 1-W 24SOIC
• Manufacturer: Maxim Integrated Products

Specifications of DS2490Y

• Applications: USB
• Interface: 1-Wire
• Voltage - Supply: 3 V ~ 5.5 V
• Package / Case: 24-SOIC (7.5mm Width)
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

READ CRC PROT PAGE—This command is used to read one or multiple CRC-protected pages of
EPROM devices and to read tamper-detect bytes and counter value of Monetary iButtons. If embedded
command bit DT = 1, the CRC16 generator is selected; if DT = 0, CRC8 is used. Embedded command bit
CIB is used to specify either a 2- or 3-byte read preamble. Additionally, embedded command bit F can be
used to clear the Communication command buffer and EP2/3 FIFOs if an error occurs during execution
of the command. The command can also be used to read a single partial page up to the end of that page
and reading the PIOs of a DS2406. This command is also applicable to the Read IPR function of the
crypto iButton if CIB = 1. The EP2 FIFO must be pre-filled with preamble data before command
execution. To prevent overflow, the EP3 FIFO must be monitored (and read if necessary) during
command execution if reading more data than the size of the EP3 FIFO.
READ REDIRECT PAGE W/CRC—This command is used to read a single page of data and check the
CRC. If the page is not redirected, the host will receive the page number and all its data. If the page is
redirected and embedded command bit CH = 1 the device will follow the trail of redirections until a page
is found that is not redirected. When found, the host will receive the page number and all data of that
particular page. If CH = 0 and the first read attempt reveals a redirection the host will only receive the
number of the page the addressed page is redirected to. Reading starts at a page boundary. Additionally,
embedded command bit F can be used to clear the communication command buffer and EP2/3 FIFOs if
an error occurs during execution of the command. An NRS error code is an indication of an infinite loop.
The EP2 FIFO must be pre-filled with ROM ID and command code data before command execution. To
prevent overflow, the EP3 FIFO must be monitored (and read if necessary) during command execution if
reading more data than the size of the EP3 FIFO.
Command parameters:
EP2 data:
EP3 data:
Result Register:
If CIB = 0: 3-bytes
If CIB = 1: 2-bytes
2 bytes: 1 byte page size, 1 byte number of pages. Note that the Page
Size byte parameter value must be of the form log
For example, if the actual page size is 32
parameter would need to be 0x05. Typical page sizes are 32 decimal for
data memory and 8 for status memory. A page size of 0x00 indicates a
256-byte page.
Length
Length
(page size x
number of
pages)
Code
CRC
0x00
None
None
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3-byte preamble: 1-Wire command code, TA1, TA2
(typical).
2-byte preamble: 1-Wire command code, length
information.
Description
Data read from the 1-Wire device.
Condition
ICP = 0, NTF = 0 or 1: and an error condition.
ICP = 0, NTF = 1: no error detected
ICP = 0, NTF = 0: no error detected
ICP = 1
10
, then the Page Size
2
(actual page size).