參數(shù)資料
型號(hào)： DS21FT40
元件分類： 通信及網(wǎng)絡(luò)
英文描述： Ultraframer DS3/E3/DS2/E2/DS1/E1/DS0
中文描述： Ultraframer DS3/E3/DS2/E2/DS1/E1/DS0
文件頁數(shù)： 57/87頁
文件大?。?/td> 386K
代理商： DS21FT40
DS21FT40
57 of 87
Like the other status registers in the framer, the user will always proceed a read of any of the three
registers with a write. The byte written to the register will inform the framer which of the latched bits the
user wishes to read and have cleared (the real time bits are not affected by writing to the status register).
The user will write a byte to one of these registers, with a one in the bit positions he or she wishes to read
and a zero in the bit positions he or she does not wish to obtain the latest information on. When a one is
written to a bit location, the read register will be updated with current value and it will be cleared. When
a zero is written to a bit position, the read register will not be updated and the previous value will be held.
A write to the status and information registers will be immediately followed by a read of the same
register. The read result should be logically AND’ed with the mask byte that was just written and this
value should be written back into the same register to insure that bit does indeed clear. This second write
step is necessary because the alarms and events in the status registers occur asynchronously in respect to
their access via the parallel port. This write–read–write (for polled driven access) or write–read (for
interrupt driven access) scheme allows an external microcontroller or microprocessor to individually poll
certain bits without disturbing the other bits in the register. This operation is key in controlling the
DS21FT40 with higher–order software languages.
Like the SR1 and SR2 status registers, the HSR register has the unique ability to initiate a hardware
interrupt via the INT* output pin. Each of the events in the HSR can be either masked or unmasked from
the interrupt pin via the HDLC Interrupt Mask Register (HIMR). Interrupts will force the INT* pin low
when the event occurs. The INT* pin will be allowed to return high (if no other interrupts are present)
when the user reads the event bit that caused the interrupt to occur.
14.3 BASIC OPERATION DETAILS
As a basic guideline for interpreting and sending HDLC messages, the following sequences can be
applied:
Receive a HDLC Message
1.
Enable RPS interrupts.
2.
Wait for interrupt to occur.
3.
Disable RPS interrupt and enable either RPE, RNE, or RHALF interrupt.
4.
Read RHIR to obtain REMPTY status.
A. If REMPTY=0, then record OBYTE, CBYTE, and POK bits and then read the FIFO
A1. If CBYTE=0 then skip to step 5
A2. If CBYTE=1 then skip to step 7
B. If REMPTY=1, then skip to step 6
5.
Repeat step 4.
6.
Wait for interrupt, skip to step 4.
7.
If POK=0, then discard whole packet, if POK=1, accept the packet.
8.
Disable RPE, RNE, or RHALF interrupt, enable RPS interrupt and return to step 1.
相關(guān)PDF資料
PDF描述
DS21FT42 Ultraframer DS3/E3/DS2/E2/DS1/E1/DS0
DS21Q50N Telecommunication IC
DS21Q55DK Quad T1/E1/J1 Transceiver Design Kit Daughter Card
DS21Q55 Quad T1/E1/J1 Transceiver
DS21Q55N Quad T1/E1/J1 Transceiver
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS21FT40N 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述:
DS21FT42 功能描述:網(wǎng)絡(luò)控制器與處理器 IC 4x4 16/4x3 12 Chnl T1/T1 Framer RoHS:否 制造商:Micrel 產(chǎn)品:Controller Area Network (CAN) 收發(fā)器數(shù)量: 數(shù)據(jù)速率: 電源電流（最大值）:595 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PBGA-400 封裝:Tray
DS21FT42N 功能描述:網(wǎng)絡(luò)控制器與處理器 IC 4x4 16/4x3 12 Chnl T1/T1 Framer RoHS:否 制造商:Micrel 產(chǎn)品:Controller Area Network (CAN) 收發(fā)器數(shù)量: 數(shù)據(jù)速率: 電源電流（最大值）:595 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PBGA-400 封裝:Tray
DS21FT44 功能描述:網(wǎng)絡(luò)控制器與處理器 IC RoHS:否 制造商:Micrel 產(chǎn)品:Controller Area Network (CAN) 收發(fā)器數(shù)量: 數(shù)據(jù)速率: 電源電流（最大值）:595 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PBGA-400 封裝:Tray
DS21FT44+ 功能描述:網(wǎng)絡(luò)控制器與處理器 IC 4X3 E1 Framer E1 Framer E1 Framer RoHS:否 制造商:Micrel 產(chǎn)品:Controller Area Network (CAN) 收發(fā)器數(shù)量: 數(shù)據(jù)速率: 電源電流（最大值）:595 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PBGA-400 封裝:Tray
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*