参数资料
型号: XR19L210IL40-F
厂商: Exar Corporation
文件页数: 42/43页
文件大小: 0K
描述: IC UART/TXRX RS232 40QFN
标准包装: 490
特点: *
通道数: 1,UART
FIFO's: 16 字节
规程: RS232
电源电压: 3 V ~ 5.5 V
带自动流量控制功能:
带故障启动位检测功能:
带调制解调器控制功能:
带CMOS:
安装类型: 表面贴装
封装/外壳: 40-VFQFN 裸露焊盘
供应商设备封装: 40-QFN 裸露焊盘(6x6)
包装: 托盘
XR19L210
8
SINGLE CHANNEL INTEGRATED UART AND RS-232 TRANSCEIVER
REV. 1.0.2
2.8
Crystal or External Clock Input
The L210 includes an on-chip oscillator (XTAL1 and XTAL2) to generate a clock when a crystal is connected
between the XTAL1 and XTAL2 pins of the device. Alternatively, an external clock can be supplied through the
XTAL1 pin. The CPU data bus does not require this clock for bus operation. The crystal oscillator provides a
system clock to the Baud Rate Generators (BRG) section found in each of the UART. XTAL1 is the input to the
oscillator or external clock input and XTAL2 pin is the bufferred output which can be used as a clock signal for
other devices in the system. Please note that the input XTAL1 is not 5V tolerant and therefore, the maximum
voltage at the pin should be VCC when an external clock is supplied. For programming details, see
“Programmable Baud Rate Generator.”
The on-chip oscillator is designed to use an industry standard microprocessor crystal (parallel resonant,
fundamental frequency with 10-22 pF capacitance load, ESR of 20-120 ohms and 100ppm frequency
tolerance) connected externally between the XTAL1 and XTAL2 pins. When VCC = 5V, the on-chip oscillator
can operate with a crystal whose frequency is not greater than 24 MHz. On the other hand, the L210 can
accept an external clock of up to 50MHz at XTAL1 pin also. Although the L210 can accept an exteran clock of
up to 50MHz, the maximum data rate supported by the RS-232 drivers is 250Kbps. For further reading on the
oscillator circuit please see the Application Note DAN108 on the EXAR web site at http://www.exar.com.
2.9
Programmable Baud Rate Generator
The L210 UART has its own Baud Rate Generator (BRG) with a prescaler. The prescaler is controlled by a
software bit (bit-7) in the MCR register. This bit selects the prescaler to divide the input crystal or external clock
by a factor of 1 or 4. The clock output of the prescaler goes to the BRG. The BRG further divides this clock by
a programmable divisor (via DLL and DLM registers) between 1 and (216 -1) to obtain a 16X sampling rate
clock of the serial data rate. The sampling rate clock is used by the transmitter for data bit shifting and receiver
for data sampling. The BRG divisor defaults to the maximum baud rate (DLL = 0x01 and DLM = 0x00) upon
power up.
TABLE 2: INT (IRQ#) PIN OPERATION FOR RECEIVER
FCR BIT-0 = 0
(FIFO DISABLED)
FCR BIT-0 = 1
(FIFO ENABLED)
INT Pin
(I/M# = 1)
0 = no data
1 = 1 byte
0 = FIFO below trigger level
1 = FIFO above trigger level
IRQ# Pin
(I/M# = 0)
1 = no data
0 = 1 byte
1 = FIFO below trigger level
0 = FIFO above trigger level
FIGURE 4. TYPICAL CRYSTAL CONNECTIONS
C1
22-47pF
C2
22-47pF
Y1
1.8432 MHz
to
24 MHz
R1
0-120
(Optional)
R2
500K - 1M
XTAL1
XTAL2
相关PDF资料
PDF描述
XR19L212IL48-F IC UART/TXRX RS232 48QFN
XR19L220IL40-F IC UART/TXRX RS232 40QFN
XR19L222IL64-F IC UART/TXRX RS232 64QFN
XR19L400IL40-F IC UART/TXRX RS485 40QFN
XR19L402IL48-F IC UART/TXRX RS485 48QFN
相关代理商/技术参数
参数描述
XR19L212 制造商:EXAR 制造商全称:EXAR 功能描述:TWO CHANNEL INTEGRATED UART AND RS-232 TRANSCEIVER
XR19L212IL48 制造商:EXAR 制造商全称:EXAR 功能描述:TWO CHANNEL INTEGRATED UART AND RS-232 TRANSCEIVER
XR19L212IL48-0B-EB 功能描述:界面开发工具 Supports L212 48 pin QFN, PCI 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
XR19L212IL48-F 功能描述:UART 接口集成电路 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
XR19L212IL48TR-F 制造商:Exar Corporation 功能描述:UART 2-CH 64Byte FIFO 5V 48-Pin QFN EP T/R 制造商:Exar Corporation 功能描述:XR19L212IL48TR-F