- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄11542 > DS21Q42T (Maxim Integrated Products)IC FRAMER ENHANCED T1 4X 128TQFP PDF資料下載
參數(shù)資料
| 型號(hào)： | DS21Q42T |
| 廠商： | Maxim Integrated Products |
| 文件頁(yè)數(shù)： | 71/116頁(yè) |
| 文件大小： | 0K |
| 描述： | IC FRAMER ENHANCED T1 4X 128TQFP |
| 標(biāo)準(zhǔn)包裝： | 72 |
| 控制器類型： | T1 調(diào)幀器 |
| 接口： | 并行/串行 |
| 電源電壓： | 2.97 V ~ 3.63 V |
| 電流 - 電源： | 75mA |
| 工作溫度： | 0°C ~ 70°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 128-LQFP |
| 供應(yīng)商設(shè)備封裝： | 128-LQFP（14x20） |
| 包裝： | 管件 |
第1頁(yè)第2頁(yè)第3頁(yè)第4頁(yè)第5頁(yè)第6頁(yè)第7頁(yè)第8頁(yè)第9頁(yè)第10頁(yè)第11頁(yè)第12頁(yè)第13頁(yè)第14頁(yè)第15頁(yè)第16頁(yè)第17頁(yè)第18頁(yè)第19頁(yè)第20頁(yè)第21頁(yè)第22頁(yè)第23頁(yè)第24頁(yè)第25頁(yè)第26頁(yè)第27頁(yè)第28頁(yè)第29頁(yè)第30頁(yè)第31頁(yè)第32頁(yè)第33頁(yè)第34頁(yè)第35頁(yè)第36頁(yè)第37頁(yè)第38頁(yè)第39頁(yè)第40頁(yè)第41頁(yè)第42頁(yè)第43頁(yè)第44頁(yè)第45頁(yè)第46頁(yè)第47頁(yè)第48頁(yè)第49頁(yè)第50頁(yè)第51頁(yè)第52頁(yè)第53頁(yè)第54頁(yè)第55頁(yè)第56頁(yè)第57頁(yè)第58頁(yè)第59頁(yè)第60頁(yè)第61頁(yè)第62頁(yè)第63頁(yè)第64頁(yè)第65頁(yè)第66頁(yè)第67頁(yè)第68頁(yè)第69頁(yè)第70頁(yè)當(dāng)前第71頁(yè)第72頁(yè)第73頁(yè)第74頁(yè)第75頁(yè)第76頁(yè)第77頁(yè)第78頁(yè)第79頁(yè)第80頁(yè)第81頁(yè)第82頁(yè)第83頁(yè)第84頁(yè)第85頁(yè)第86頁(yè)第87頁(yè)第88頁(yè)第89頁(yè)第90頁(yè)第91頁(yè)第92頁(yè)第93頁(yè)第94頁(yè)第95頁(yè)第96頁(yè)第97頁(yè)第98頁(yè)第99頁(yè)第100頁(yè)第101頁(yè)第102頁(yè)第103頁(yè)第104頁(yè)第105頁(yè)第106頁(yè)第107頁(yè)第108頁(yè)第109頁(yè)第110頁(yè)第111頁(yè)第112頁(yè)第113頁(yè)第114頁(yè)第115頁(yè)第116頁(yè)
DS21Q42
58 of 116
13.
ELASTIC STORES OPERATION
Each framer in the DS21Q42 contains dual two–frame (386 bits) elastic stores, one for the receive
direction, and one for the transmit direction. These elastic stores have two main purposes. First, they can
be used to rate convert the T1 data stream to 2.048 Mbps (or a multiple of 2.048 Mbps) which is the E1
rate. Secondly, they can be used to absorb the differences in frequency and phase between the T1 data
stream and an asynchronous (i.e., not frequency locked) backplane clock (which can be 1.544 MHz or
2.048 MHz). The backplane clock can burst at rates up to 8.192 MHz. Both elastic stores contain full
controlled slip capability which is necessary for this second purpose. Both elastic stores within the
framer are fully independent and no restrictions apply to the sourcing of the various clocks that are
applied to them. The transmit side elastic store can be enabled whether the receive elastic store is enabled
or disabled and vice versa. Also, each elastic store can interface to either a 1.544 MHz or 2.048 MHz
backplane without regard to the backplane rate the other elastic store is interfacing.
Two mechanisms are available to the user for resetting the elastic stores. The Elastic Store Reset (TX -
CCR7.4 & RX - CCR7.5) function forces the elastic stores to a depth of one frame unconditionally. Data
is lost during the reset. The second method, the Elastic Store Align (TX - CCR6.5 & RX - CCR6.6)
forces the elastic store depth to a minimum depth of half a frame only if the current pointer separation is
already less then half a frame. If a realignment occurs data is lost. In both mechanisms, independent
resets are provided for both the receive and transmit elastic stores.
13.1 Receive Side
If the receive side elastic store is enabled (CCR1.2=1), then the user must provide either a 1.544 MHz
(CCR1.3=0) or 2.048 MHz (CCR1.3=1) clock at the RSYSCLK pin. The user has the option of either
providing a frame/multiframe sync at the RSYNC pin (RCR2.3=1) or having the RSYNC pin provide a
pulse on frame boundaries (RCR2.3=0). If the user wishes to obtain pulses at the frame boundary, then
RCR2.4 must be set to zero and if the user wishes to have pulses occur at the multiframe boundary, then
RCR2.4 must be set to one. The framer will always indicate frame boundaries via the RFSYNC output
whether the elastic store is enabled or not. If the elastic store is enabled, then multiframe boundaries will
be indicated via the RMSYNC output. If the user selects to apply a 2.048 MHz clock to the RSYSCLK
pin, then the data output at RSER will be forced to all ones every fourth channel. Hence channels 1
(except for the MSB), 5, 9, 13, 17, 21, 25, and 29 (timeslots 0, 4, 8, 12, 16, 20, 24, and 28) will be forced
to a one. The F–bit will be passed in the MSB of channel 1. Also, in 2.048 MHz applications, the
RCHBLK output will be forced high during the same channels as the RSER pin. See Section 19 for more
details. This is useful in T1 to CEPT (E1) conversion applications. If the 386–bit elastic buffer either
fills or empties, a controlled slip will occur. If the buffer empties, then a full frame of data (193 bits) will
be repeated at RSER and the SR1.4 and RIR1.3 bits will be set to a one. If the buffer fills, then a full
frame of data will be deleted and the SR1.4 and RIR1.4 bits will be set to a one.
13.2 Transmit Side
The operation of the transmit elastic store is very similar to the receive side. The transmit side elastic
store is enabled via CCR1.7. A 1.544 MHz (CCR1.4=0) or 2.048 MHz (CCR1.4=1) clock can be applied
to the TSYSCLK input. If the user selects to apply a 2.048 MHz clock to the TSYSCLK pin, then the
data input at TSER will be ignored every fourth channel. Hence channels 1 (except for the MSB), 5, 9,
13, 17, 21, 25, and 29 (timeslots 0, 4, 8, 12, 16, 20, 24, and 28) will be ignored. A special case exists for
the MSB of channel 1. Via TCR1.6 the MSB of channel 1 can be sampled as the F-bit. The user must
supply a 8 kHz frame sync pulse to the TSSYNC input. Also, in 2.048 MHz applications, the TCHBLK
output will be forced high during the channels ignored by the framer. See Section 19 for more details.
Controlled slips in the transmit elastic store are reported in the RIR2.3 bit and the direction of the slip is
reported in the RIR2.5 and RIR2.4 bits.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| V72A28C400B | CONVERTER MOD DC/DC 28V 400W |
| DS21Q44T | IC FRAMER ENHANCED E1 4X 128TQFP |
| V72A24C400BF | CONVERTER MOD DC/DC 24V 400W |
| XCCACE-TQ144I | IC ACE CONTROLLER CHIP |
| VI-21W-IY-B1 | CONVERTER MOD DC/DC 5.5V 50W |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS21Q42T+ | 功能描述:網(wǎng)絡(luò)控制器與處理器 IC Enhanced Quad 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 |
| DS21Q42TN | 功能描述:網(wǎng)絡(luò)控制器與處理器 IC Enhanced Quad 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 |
| DS21Q43A | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Quad E1 Framer |
| DS21Q43AT | 功能描述:網(wǎng)絡(luò)控制器與處理器 IC Quad 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 |
| DS21Q43AT+ | 功能描述:網(wǎng)絡(luò)控制器與處理器 IC Quad 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)。