- 您现在的位置：买卖IC网 > PDF目录97867 > DS21Q42TN (DALLAS SEMICONDUCTOR) DATACOM, FRAMER, PQFP128 PDF资料下载
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： | 89/119页 |
| 文件大小： | 1309K |
| 代理商： | DS21Q42TN |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页第55页第56页第57页第58页第59页第60页第61页第62页第63页第64页第65页第66页第67页第68页第69页第70页第71页第72页第73页第74页第75页第76页第77页第78页第79页第80页第81页第82页第83页第84页第85页第86页第87页第88页当前第89页第90页第91页第92页第93页第94页第95页第96页第97页第98页第99页第100页第101页第102页第103页第104页第105页第106页第107页第108页第109页第110页第111页第112页第113页第114页第115页第116页第117页第118页第119页
DS21Q42
71 of 119
15.2 LEGACY FDL SUPPORT
15.2.1 Overview
The DS21Q42 maintains the circuitry that existed in the previous generation of Dallas Semiconductor’s
single chip transceivers and quad framers. Section 15.2 covers the circuitry and operation of this legacy
functionality. In new applications, it is recommended that the HDLC controller and BOC controller
described in Section 15.1 be used. On the receive side, it is possible to have both the new HDLC/BOC
controller and the legacy hardware working at the same time. However this is not possible on the transmit
side since their can be only one source the of the FDL data internal to the device.
15.2.2 Receive Section
In the receive section, the recovered FDL bits or Fs bits are shifted bit–by–bit into the Receive FDL
register (RFDL). Since the RFDL is 8 bits in length, it will fill up every 2 ms (8 times 250 us). The framer
will signal an external microcontroller that the buffer has filled via the SR2.4 bit. If enabled via IMR2.4,
the INT* pin will toggle low indicating that the buffer has filled and needs to be read. The user has 2 ms
to read this data before it is lost. If the byte in the RFDL matches either of the bytes programmed into the
RMTCH1 or RMTCH2 registers, then the SR2.2 bit will be set to a one and the INT* pin will toggled
low if enabled via IMR2.2. This feature allows an external microcontroller to ignore the FDL or Fs
pattern until an important event occurs.
The framer also contains a zero destuffer, which is controlled via the CCR2.0 bit. In both ANSI T1.403
and TR54016, communications on the FDL follows a subset of a LAPD protocol. The LAPD protocol
states that no more than 5 ones should be transmitted in a row so that the data does not resemble an
opening or closing flag (01111110) or an abort signal (11111111). If enabled via CCR2.0, the DS21Q42
will automatically look for 5 ones in a row, followed by a zero. If it finds such a pattern, it will
automatically remove the zero. If the zero destuffer sees six or more ones in a row followed by a zero, the
zero is not removed. The CCR2.0 bit should always be set to a one when the DS21Q42 is extracting the
FDL. More on how to use the DS21Q42 in FDL applications in this legacy support mode is covered in a
separate Application Note.
RFDL: RECEIVE FDL REGISTER (Address = 28 Hex)
(MSB)
(LSB)
RFDL7
RFDL6
RFDL5
RFDL4
RFDL3
RFDL2
RFDL1
RFDL0
SYMBOL
POSITION
NAME AND DESCRIPTION
RFDL7
RFDL.7
MSB of the Received FDL Code
RFDL0
RFDL.0
LSB of the Received FDL Code
The Receive FDL Register (RFDL) reports the incoming Facility Data Link (FDL) or the incoming Fs
bits. The LSB is received first.
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 |
发布紧急采购，3分钟左右您将得到回复。