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参数资料
| 型号： | DS2490 |
| 英文描述： | USB to 1-Wire Bridge Chip |
| 中文描述： | USB与1-Wire桥接芯片 |
| 文件页数： | 8/50页 |
| 文件大小： | 530K |
| 代理商： | DS2490 |
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DS2490
8 of 50
033199
WRITE 0 TIME SLOT
Figure 7
Speed
Regular
Overdrive
Flexible
tLOW0
62 μs
7 μs
62 μs
tREC0
6 μs
3 μs
3 to 10
μs
tSLOT
68 μs
10 μs
65 to 72
μs
*Power-up defaults for Flexible speed:
tREC0
=7μs
Pulse Wave Forms
The PULSE Communication Command can be used to generate either a strong pullup to 5V or 12V
programming pulse. The duration of the pulses are specified with the STRONG PULLUP DURATION
and PROG PULSE DURATION mode registers. Figure 8 and Figure 9 show timing of the two pulse
types. For predefined pulse durations, t
SPU
and t
PP
are known values, for semi-infinite and infinite
durations these pulse times vary and depend on the characteristics of attached 1-Wire devices and/or host
computer intervention. See the MODE COMMAND section for details on duration times. The
processing of a PULSE command is essentially the same, regardless if a strong pullup or a programming
pulse is specified. As shown in the figures, at t
1
processing of the PULSE command begins, at t
2
the
“pulse” ends.
For EPROM programming, only a single slave device should be connected to the 1-Wire bus and the
cable must be short, not to exceed a few meters. The slew rate of the rising and falling edge of the
programming pulse (“steep slopes”) is actively controlled by DS2490 as shown in Figure 9. Do not
attempt to generate a programming pulse with a non-EPROM device on the bus; this may damage the
device as well as the DS2490. In addition, a correct programming pulse can only be generated if the 12V
programming voltage is available at the VPP pin of the DS2490.
Certain applications may require a duration for a strong pullup or programming pulse that cannot be
realized using one of the predefined values (see MODE COMMANDS section for values). Selecting
infinite duration allows the host to generate pulses of any length. As a consequence, however, the host
becomes responsible to actively control the duration of the pulse. Failing to do so may require a power-
on reset or master reset cycle of the DS2490. For this reason, infinite duration should only be used if
absolutely necessary. The HALT EXECUTION WHEN DONE or HALT EXECUTION WHEN IDLE
Control commands are used to terminate an infinite duration pulse. As before, processing the command
is essentially the same, regardless if it is for a strong pullup or a programming pulse.
相关PDF资料 |
PDF描述 |
|---|---|
| DS2490S | USB to 1-Wire Bridge Chip |
| DS2502-E64 | IEEE EUI-64 Node Address Chip |
| DS26334 | 3.3V, 16-Channel, E1/T1/J1 Short and Long-Haul Line Interface Unit |
| DS26334G | 3.3V, 16-Channel, E1/T1/J1 Short and Long-Haul Line Interface Unit |
| DS26334GN | 3.3V, 16-Channel, E1/T1/J1 Short and Long-Haul Line Interface Unit |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DS2490S | 功能描述:接口 - 专用 RoHS:否 制造商:Texas Instruments 产品类型:1080p60 Image Sensor Receiver 工作电源电压:1.8 V 电源电流:89 mA 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:BGA-59 |
| DS2490S+ | 制造商:Maxim Integrated Products 功能描述:USB TO 1-WIRE BRIDGE 24SOIC W - Rail/Tube 制造商:Maxim Integrated Products 功能描述:USB 1-W BRIDGE CHIP 24-SO LF 制造商:Maxim Integrated Products 功能描述:Bulk |
| DS2490S+T&R | 制造商:Maxim Integrated Products 功能描述:USB TO 1-WIRE BRIDGE 24SOIC W - Tape and Reel |
| DS2490S+TR | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:USB to 1-Wire Bridge Chip |
| DS2490X | 制造商:未知厂家 制造商全称:未知厂家 功能描述:USB to 1-Wire Bridge Chip(468.41 k) |
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