参数资料
型号: DS21Q42TN
厂商: DALLAS SEMICONDUCTOR
元件分类: Digital Transmission Controller
英文描述: DATACOM, FRAMER, PQFP128
封装: TQFP-128
文件页数: 99/119页
文件大小: 1309K
代理商: DS21Q42TN
DS21Q42
80 of 119
19.2 TAP Controller State Machine
This section covers the details on the operation of the Test Access Port (TAP) Controller State Machine.
Please see Figure 19.2 for details on each of the states described below.
TAP Controller
The TAP controller is a finite state machine that responds to the logic level at JTMS on the rising edge of
JTCLK.
Test-Logic-Reset
Upon power up of the DS21Q42, the TAP Controller will be in the Test-Logic-Reset state. The
Instruction register will contain the IDCODE instruction. All system logic of the DS21Q42 will operate
normally.
Run-Test-Idle
The Run-Test-Idle is used between scan operations or during specific tests. The Instruction register and
Test registers will remain idle.
Select-DR-Scan
All test registers retain their previous state. With JTMS low, a rising edge of JTCLK moves the controller
into the Capture-DR state and will initiate a scan sequence. JTMS HIGH during a rising edge on JTCLK
moves the controller to the Select-IR
Capture-DR
Data may be parallel-loaded into the Test Data registers selected by the current instruction. If the
instruction does not call for a parallel load or the selected register does not allow parallel loads, the Test
register will remain at its current value. On the rising edge of JTCLK, the controller will go to the Shift-
DR state if JTMS is low or it will go to the Exit1-DR state if JTMS is high.
Shift-DR
The Test Data register selected by the current instruction will be connected between JTDI and JTDO and
will shift data one stage towards its serial output on each rising edge of JTCLK. If a Test Register
selected by the current instruction is not placed in the serial path, it will maintain its previous state.
Exit1-DR
While in this state, a rising edge on JTCLK with JTMS high will put the controller in the Update-DR
state, and terminate the scanning process. A rising edge on JTCLK with JTMS low will put the controller
in the Pause-DR state.
Pause-DR
Shifting of the test registers is halted while in this state. All Test registers selected by the current
instruction will retain their previous state. The controller will remain in this state while JTMS is low. A
rising edge on JTCLK with JTMS high will put the controller in the Exit2-DR state.
相关PDF资料
PDF描述
DS21Q42T DATACOM, FRAMER, PQFP128
DS21Q43AT DATACOM, FRAMER, PQFP128
DS21Q44T DATACOM, FRAMER, PQFP128
DS21Q44TN DATACOM, FRAMER, PQFP128
DS21Q48N DATACOM, PCM TRANSCEIVER, PBGA144
相关代理商/技术参数
参数描述
DS21Q43A 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:Quad E1 Framer
DS21Q43AT 功能描述:网络控制器与处理器 IC Quad E1 Framer RoHS:否 制造商:Micrel 产品:Controller Area Network (CAN) 收发器数量: 数据速率: 电源电流(最大值):595 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PBGA-400 封装:Tray
DS21Q43AT+ 功能描述:网络控制器与处理器 IC Quad E1 Framer RoHS:否 制造商:Micrel 产品:Controller Area Network (CAN) 收发器数量: 数据速率: 电源电流(最大值):595 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PBGA-400 封装:Tray
DS21Q43ATN 制造商:DALLAS 制造商全称:Dallas Semiconductor 功能描述:Quad E1 Framer
DS21Q43-ATN 功能描述:网络控制器与处理器 IC Quad E1 Framer RoHS:否 制造商:Micrel 产品:Controller Area Network (CAN) 收发器数量: 数据速率: 电源电流(最大值):595 mA 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:PBGA-400 封装:Tray