DS2490Y Maxim Integrated Products, DS2490Y Datasheet - Page 13

• 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

The 2-byte wValue field is encoded with the specific command. For Control and Mode commands, the
field value corresponds to a specific command constant as defined in Appendix 4. For Communication
commands, the field has additional embedded command parameters as indicated in Appendix 2. The
exception is the READ STRAIGHT command as described previously.
The 2-byte wIndex is used to hold additional command parameter data when required by the specific
command.
The wLength field is used in the control transfer setup packet to specify the number of bytes to be sent
during the data stage of a control transfer. The “GET COMM CMDS” control command is the only
DS2490 command that uses the data stage of the control transfer. Typically, all command data is
embedded in the setup stage. Except for the GET COMM CMDS, this field must be set to 0x0000.
DS2490 Control, Communication, and Mode vendor-specific command descriptions and formatting are
defined in Appendices 1, 2, and 3. Vendor-specific commands not defined in the appendices are not
supported by the DS2490 and the device will respond with a STALL if an unsupported command is
received.
MODE COMMANDS
DS2490 1-Wire characteristics and features (speed, durations, slew rate, etc.) are controlled with discrete
Mode commands and/or embedded Communication command parameters. Parameter values and
enable/disable settings are used for characteristic control. Mode settings are stored in the DS2490 State
Registers and can be read at any time or at the polling interval of EP1. See the section “DEVICE
FEEDBACK” for State Register details.
Enable/disable settings are used to control two global features:
 Strong pullup to +5V
 Dynamic 1-Wire bus communication speed change through a communication command
The settings for these three global controls are accessible only through Mode commands; the features are
either enabled or disabled with the appropriate Mode command. Specific Communication commands
exist to issue a strong pullup, or speed change. When the corresponding setting is enabled the feature is
usable as part of a communication command when disabled the feature is not usable.
Parameter values and codes are used to specify and control 1-Wire bus characteristics:
 1-Wire bus communication speed
 +5V strong pullup duration
 Pulldown slew rate
 Write-1 low time
 Data sample offset/Write-0 Recovery time
These five settings are controllable with discrete Mode commands or as embedded command/parameter
values in Communications commands.
Command Type
CONTROL_CMD
COMM_CMD
MODE_CMD
Description
1-Wire interface control commands
1-Wire interface communication commands
1-Wire interface operational mode commands
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