参数资料
| 型号： | XR16L2550IL-F |
| 厂商： | Exar Corporation |
| 文件页数： | 8/44页 |
| 文件大小： | 0K |
| 描述： | IC UART FIFO 16B DUAL 32QFN |
| 标准包装： | 490 |
| 特点： | * |
| 通道数： | 2，DUART |
| FIFO's： | 16 字节 |
| 规程： | RS232 |
| 电源电压： | 2.25 V ~ 5.5 V |
| 带自动流量控制功能： | 是 |
| 带IrDA 编码器/解码器： | 是 |
| 带故障启动位检测功能： | 是 |
| 带调制解调器控制功能： | 是 |
| 带CMOS： | 是 |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-VFQFN 裸露焊盘 |
| 供应商设备封装： | 32-QFN 裸露焊盘（5x5） |
| 包装： | 托盘 |
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XR16L2550
16
LOW VOLTAGE DUART WITH 16-BYTE FIFO
REV. 1.1.3
2.15
Auto Xon/Xoff (Software) Flow Control
When software flow control is enabled (See Table 12), the L2550 compares one or two sequential receive data
characters with the programmed Xon or Xoff-1,2 character value(s). If receive character(s) (RX) match the
programmed values, the L2550 will halt transmission (TX) as soon as the current character has completed
transmission. When a match occurs, the Xoff (if enabled via IER bit-5) flag will be set and the interrupt output
pin will be activated. Following a suspension due to a match of the Xoff character, the L2550 will monitor the
receive data stream for a match to the Xon-1,2 character. If a match is found, the L2550 will resume operation
and clear the flags (ISR bit-4).
Reset initially sets the contents of the Xon/Xoff 8-bit flow control registers to a logic 0. Following reset the user
can write any Xon/Xoff value desired for software flow control. Different conditions can be set to detect Xon/
Xoff characters (See Table 12) and suspend/resume transmissions. When double 8-bit Xon/Xoff characters
are selected, the L2550 compares two consecutive receive characters with two software flow control 8-bit
values (Xon1, Xon2, Xoff1, Xoff2) and controls TX transmissions accordingly. Under the above described flow
control mechanisms, flow control characters are not placed (stacked) in the user accessible RX data buffer or
FIFO.
In the event that the receive buffer is overfilling and flow control needs to be executed, the L2550 automatically
sends an Xoff message (when enabled) via the serial TX output to the remote modem. The L2550 sends the
Xoff-1,2 characters two-character-times (= time taken to send two characters at the programmed baud rate)
after the receive FIFO crosses the programmed trigger level. To clear this condition, the L2550 will transmit the
programmed Xon-1,2 characters as soon as receive FIFO is less than one trigger level below the programmed
trigger level. See Table 6 below.
TABLE 6: AUTO XON/XOFF (SOFTWARE) FLOW CONTROL
RX TRIGGER LEVEL
INT PIN ACTIVATION
XOFF CHARACTER(S) SENT
(CHARACTERS IN RX FIFO)
XON CHARACTER(S) SENT
(CHARACTERS IN RX FIFO)
1
1*
0
4
4*
1
8
8*
4
14
14*
8
* After the trigger level is reached, an xoff character is sent after a short span of time (= time required to send 2
characters); for example, after 2.083ms has elapsed for 9600 baud and 8-bit word length, no parity and 1 stop bit setting.
2.16
Special Character Detect
A special character detect feature is provided to detect an 8-bit character when bit-5 is set in the Enhanced
Feature Register (EFR). When this character (Xoff2) is detected, it will be placed in the FIFO along with normal
incoming RX data.
The L2550 compares each incoming receive character with Xoff-2 data. If a match exists, the received data will
be transferred to FIFO and ISR bit-4 will be set to indicate detection of special character. Although the Internal
Register Table shows Xon, Xoff Registers with eight bits of character information, the actual number of bits is
dependent on the programmed word length. Line Control Register (LCR) bits 0-1 defines the number of
character bits, i.e., either 5 bits, 6 bits, 7 bits, or 8 bits. The word length selected by LCR bits 0-1 also
determines the number of bits that will be used for the special character comparison. Bit-0 in the Xon, Xoff
Registers corresponds with the LSB bit for the receive character.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| XR16L2550ILTR-F | 制造商:Exar Corporation 功能描述:UART 2-CH 16Byte FIFO 2.5V/3.3V/5V 32-Pin QFN EP T/R 制造商:Exar Corporation 功能描述:XR16L2550ILTR-F |
| XR16L2550IM | 制造商:Rochester Electronics LLC 功能描述: 制造商:Exar Corporation 功能描述: |
| XR16L2550IM-0A-EB | 功能描述:界面开发工具 Supports L2550 48 ld TQFP, ISA Interface RoHS:否 制造商:Bourns 产品:Evaluation Boards 类型:RS-485 工具用于评估:ADM3485E 接口类型:RS-485 工作电源电压:3.3 V |
| XR16L2550IM-0B-EB | 功能描述:UART 接口集成电路 Supports L2550 48 ld TQFP, PCI Interface RoHS:否 制造商:Texas Instruments 通道数量:2 数据速率:3 Mbps 电源电压-最大:3.6 V 电源电压-最小:2.7 V 电源电流:20 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:LQFP-48 封装:Reel |
| XR16L2550IM-F | 功能描述:UART 接口集成电路 2.5V-5.5V 16B FIFO temp -45 to 85C;UART RoHS:否 制造商:Texas Instruments 通道数量:2 数据速率:3 Mbps 电源电压-最大:3.6 V 电源电压-最小:2.7 V 电源电流:20 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:LQFP-48 封装:Reel |
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