DS2490Y Maxim Integrated Products, DS2490Y Datasheet - Page 14

• 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

As listed in Table 5 and summarized previously, there are eight Mode commands. The USB control
transfer setup packet coding to transmit these commands is detailed in Appendix 3. Mode commands are
immediately processed by the DS2490 when they are received. The DS2490 power-on default values for
these parameters are as listed in Table 11. Each command and parameter control is detailed in the
following paragraphs.
Mode Command Set Summary Table 5
Mode Command Set Descriptions:
ENABLE PULSE—This command is used to enable or disable a 1-Wire strong pullup pulse to 5V. One
bit position in the parameter byte is used to control the enabled/disabled state for the pulse. The pulse is
enabled when the respective bit is set to a 1 and disabled when set to a 0. The DS2490 power-up default
state for strong pullup is disabled.
ENABLE SPEED CHANGE—This command is used to enable or disable a 1-Wire communication
speed change. Enabled when a TRUE parameter value is passed with the command, disabled with a
FALSE. The DS2490 power-up default state for speed change is disabled.
1-WIRE SPEED—This command is used to set the speed of 1-Wire communication; three settings are
possible. The parameter codes to select the desired or required speed are as listed in Table 6. As shown,
speed codes 0x3..0xF are undefined. The DS2490 decodes the 3 LSBs of the 1-Wire speed code. Sending
a code other than the defined values in Table 6 will result in undefined behavior. The DS2490 power-up
default communication speed is regular.
1-Wire Bus Speed Codes Table 6
Command
ENABLE PULSE
ENABLE SPEED
CHANGE
1-WIRE SPEED
STRONG PULLUP
DURATION
PULLDOWN SLEW
RATE
WRITE-1 LOW TIME
DSOW0 RECOVERY
TIME
0x3..0xF
Code
0x0
0x1
0x2
Overdrive 10s time slot (100kbps)
reserved
Flexible
Regular
Speed
Data Rate
65s time slot (15.4kbps)
65s to 72s time slot
(13.9kbps to 15.4kbps)
undefined
Function
Enable/disable 1-Wire strong pullup pulse to 5V.
Enable/disable dynamic change of the 1-Wire speed through a
communication command.
Communication speed of the 1-Wire bus.
Duration of 1-Wire strong pullup.
Slew rate of 1-Wire pulldown.
Duration of 1-Wire Write-1 low time.
Recovery time for the 1-Wire data sample offset / Write-0 transaction.
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