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参数资料
| 型号： | DS2480 |
| 英文描述： | Serial 1.Wire Line Driver |
| 中文描述： | 串行、1-Wire线驱动器 |
| 文件页数： | 13/26页 |
| 文件大小： | 185K |
| 代理商： | DS2480 |
DS2480
042498 13/26
TIMING DIAGRAMS
This section explains the wave forms generated by the
DS2480 on the 1–Wire bus in detail. First the commu-
nication wave forms such as the Reset/Presence
Detect Sequence and the time slots are discussed.
After that follows a detailed description of the pulse
function under various conditions. The wave forms as
generated by the DS2480 may deviate slightly from
specifications found in the “Book of DS19xx iButton
Standards” or in data sheets of 1–Wire slave devices.
However, at a closer look one will find that all of the tim-
ing requirements are met.
1–WIRE COMMUNICATION WAVE FORMS
One of the major features of the DS2480 is that it
relieves the host from generating the timing of the
1–Wire signals and sampling the 1–Wire bus at the
appropriate times. How this is done for the reset/pres-
ence detect sequence is shown in Figure 6a. This
sequence is composed of four timing segments: the
reset low time t
RSTL
, the short/interrupt sampling offset
t
SI
, the presence detect sampling offset t
PDT
and a delay
time t
FILL
. The timing segments t
SI
, t
PDT
and t
FILL
com-
prise the reset high time t
RSTH
where 1–Wire slave
devices assert their presence or interrupt pulse. During
this time the DS2480 pulls the 1–Wire bus high with its
weak pull–up current.
The values of all timing segments for all 1–Wire speed
options are shown in the table. Since the reset/presence
sequence is slow compared to the time slots, the values
for regular and flexible speed are the same. Except for
the falling edge of the presence pulse all edges are con-
trolled by the DS2480. The shape of the uncontrolled
falling edge is determined by the capacitance of the
1–Wire bus and the number, speed and sink capability
of the slave devices connected.
Reset/Presence Detect
Figure 6a
TESTING FOR SHORT AND/OR INTERRUPT
PRESENCE TESTING
UNCONTROLLED
FALLING EDGE
t
SI
RESET/PRESENCE SEQUENCE
t
RSTH
t
RSTL
PRESENCE
PULSE
5V
0V
t
FILL
TIME
SLOT
IDLE
TIME
t
PDT
Speed
t
RSTL
t
SI
t
PDT
t
FILL
t
RSTH
Regular
512
μ
s
8
μ
s
64
μ
s
512
μ
s
584
μ
s
Overdrive
64
μ
s
2
μ
s
8
μ
s
64
μ
s
74
μ
s
Flexible
512
μ
s
8
μ
s
64
μ
s
512
μ
s
584
μ
s
After having received the command code for generating
a reset/presence sequence, the DS2480 pulls the
1–Wire bus low for t
RSTL
and then lets it go back to 5V.
The DS2480 will now wait for the short/interrupt sam-
pling offset t
SI
to expire and then test the voltage on the
1–Wire bus to determine if there is a short or an interrupt
signal. If there is no short or interrupt (as shown in the
picture), the DS2480 will wait for t
PDT
and test the volt-
age on the 1–Wire bus for a presence pulse. Regardless
of the result of the presence test, the DS2480 will then
wait for t
FILL
to expire and then send the command
response byte to the host.
If the test for interrupt or short reveals a logic 0, the
DS2480 will wait for 4096
μ
s and then test the 1–Wire
bus again. If a logic 0 is detected, the 1–Wire bus is
shorted and a command response byte with the code for
SHORT will be sent immediately. If a logic 1 is detected,
the device will wait for t
FILL
to expire after which it will
send the command response byte with the code for an
alarming presence pulse. No additional testing for a
presence pulse will be done. The DS2480 will perform
the short/interrupt testing as described also at Over-
drive speed, although interrupt signaling is only defined
for regular speed.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS2480B | 功能描述:缓冲器和线路驱动器 RoHS:否 制造商:Micrel 输入线路数量:1 输出线路数量:2 极性:Non-Inverting 电源电压-最大:+/- 5.5 V 电源电压-最小:+/- 2.37 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:MSOP-8 封装:Reel |
| DS2480B | 制造商:Maxim Integrated Products 功能描述:IC SERIAL LINE DRIVER 2480 SOIC8 |
| DS2480B/T&R | 功能描述:缓冲器和线路驱动器 RoHS:否 制造商:Micrel 输入线路数量:1 输出线路数量:2 极性:Non-Inverting 电源电压-最大:+/- 5.5 V 电源电压-最小:+/- 2.37 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:MSOP-8 封装:Reel |
| DS2480B+ | 功能描述:缓冲器和线路驱动器 Serial - 1-Wire Line Driver RoHS:否 制造商:Micrel 输入线路数量:1 输出线路数量:2 极性:Non-Inverting 电源电压-最大:+/- 5.5 V 电源电压-最小:+/- 2.37 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:MSOP-8 封装:Reel |
| DS2480B+R | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:Serial to 1-Wire Line Driver |
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