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| 型号： | DS26900LN+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 16/49页 |
| 文件大小： | 0K |
| 描述： | IC JTAG MUX/SWITCH 144-LQFP |
| 标准包装： | 90 |
| 系列： | * |
| 功能： | * |
| 电压电源： | 单电源 |
| 电压 - 电源，单路/双路(±)： | 3.14 V ~ 3.47 V |
| 电流 - 电源： | * |
| 工作温度： | * |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 144-LQFP |
| 供应商设备封装： | 144-LQFP（20x20） |
| 包装： | 托盘 |
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__________________________________________________________________________________________DS26900
23
4.2
Master Arbitration
The DS26900 can have one of three possible master ports: External Test Master (ETM), Test Master 1 (TM1), or
Test Master 2 (TM2). The TM1 and TM2 ports can be bidirectional based on the state of the configuration bit
TM_SLAVE. An application, which has less than three masters, can use any combination of master ports.
Table 4-2 lists the possible signal configurations and arbitrations for master. In the table, BLOCKED indicates that
the JTAG signals are ignored both to and from this port, SLAVE indicates that this port is a target for the JTAG
master, MASTER indicates the JTAG signal source port, CONFIG indicates the configuration mode for the
DS26900, and NORMAL indicates normal JTAG signal operation from master to slave.
Table 4-2. Master Arbitration
EREQ ECFG TMREQ1 TRST1 TMREQ2 TRST2
ACTIVE
MASTER
MODE
TM1
INTERFACE
MODE
TM2
INTERFACE
MODE
L
X
L
X
ETM
CONFIG
BLOCKED
L
H
L
X
L
X
ETM
NORMAL
BLOCKED
L
H
L
X
H
X
ETM
NORMAL
BLOCKED
SLAVE
L
H
X
L
X
ETM
NORMAL
SLAVE
BLOCKED
L
H
X
H
X
ETM
NORMAL
SLAVE
H
X
L
X
TM1
CONFIG
MASTER
BLOCKED
H
X
L
H
L
X
TM1
NORMAL
MASTER
BLOCKED
H
X
H
X
L
TM2
CONFIG
SLAVE
MASTER
H
X
H
X
L
H
TM2
NORMAL
SLAVE
MASTER
H
X
H
X
H
X
NONE
INACTIVE
SLAVE
Note: Slave mode of TM1 and TM2 is affected by the state of the configuration bit TM_SLAVE.
L = Connect = VSS; H = Connect = VDD; X = Don’t care
Only one master is allowed at any time. A test master that is in slave mode has the sense of all the JTAG signals
reversed (outputs become inputs, inputs become outputs, and only
TMREQ does not change), and it functions
identically to a secondary port. A test master that is blocked has its control signals ignored (the JTAG outputs are
blocked, JTAG inputs are set to a constant logic level,
TMREQ is unaffected). Since the TM ports lack a separate
configuration signal,
TRST functions as the configuration signal. To avoid glitches on the output secondary ports, all
the master signals (TMS, TDI, TDO, and CLK) should be set to logic 0 while switching the master to/from Test
Master 1 or Test Master 2. The TM1/TM2 slave interface mode will additionally be affected by the state of the
configuration bit TM_SLAVE.
If an active master is not present (
EREQ, TMREQ1, and TMREQ2 are all logic 1), the Switch TAP Controller goes
into Test-Logic-Reset and the content of the instruction register is cleared. All other registers retain their values.
The MSB of the last instruction, before clearing, is always retained in a separate register unless global reset is
asserted. The port whose address is in the Secondary Port Selection Register (SPSR) is technically still selected,
and that port will not be affected by the state of the DPDV bit in the Device Configuration Register (DCR). If a
different master becomes the active master, communications can resume with the port whose address is in the
Secondary Port Selection Register and whose instruction register MSB is of the proper value. The Secondary Port
Selection Register should be written with all zeros once communications with secondary ports is completed.
A DS26900 in Deselect Mode disables detection of
EREQ, TMREQ1, and TMREQ2, and the device therefore acts
as if an active master is not present. Deselect Mode is selected when the mode pins (M[1:0]) are both asserted
high.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS26900LN+ | 功能描述:多路器开关 IC JTAG MUX RoHS:否 制造商:Texas Instruments 通道数量:1 开关数量:4 开启电阻（最大值）:7 Ohms 开启时间（最大值）: 关闭时间（最大值）: 传播延迟时间:0.25 ns 工作电源电压:2.3 V to 3.6 V 工作电源电流: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:UQFN-16 |
| DS26900N+ | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:JTAG Multiplexer/Switch |
| DS26C31 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:CMOS QUAD TRI-STATE DIFFERENTIAL LINE DRIVER |
| DS26C31 DIE | 制造商:Texas Instruments 功能描述: |
| DS26C31_BBA3026X WAF | 制造商:Texas Instruments 功能描述: |
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