参数资料
| 型号： | XR16V2552IL-F |
| 厂商： | Exar Corporation |
| 文件页数： | 2/46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，RS422 |
| 电源电压： | 2.25 V ~ 3.6 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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XR16V2552
10
HIGH PERFORMANCE DUART WITH 16-BYTE FIFO
REV. 1.0.3
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 100 ppm frequency
tolerance) connected externally between the XTAL1 and XTAL2 pins (see Figure 4). The programmable Baud
Rate Generator is capable of operating with a crystal oscillator frequency of up to 32 MHz at 2.5V. However,
with an external clock input on XTAL1 pin, it can extend its operation up to 64 MHz (16 Mbps serial data rate)
at 3.3V with a 4X sampling rate. For further reading on the oscillator circuit please see the Application Note
DAN108 on the EXAR web site at http://www.exar.com.
2.10
Programmable Baud Rate Generator with Fractional Divisor
Each UART has its own Baud Rate Generator (BRG) with a prescaler for the transmitter and receiver. The
prescaler is controlled by a software bit in the MCR register. The MCR register bit-7 sets the prescaler to divide
the input crystal or external clock by 1 or 4. The output of the prescaler clocks to the BRG. The BRG further
divides this clock by a programmable divisor between 1 and (216 - 0.0625) in increments of 0.0625 (1/16) to
obtain a 16X or 8X or 4X sampling clock of the serial data rate. The sampling clock is used by the transmitter
for data bit shifting and receiver for data sampling. The BRG divisor (DLL, DLM and DLD registers) defaults to
the value of ’1’ (DLL = 0x01, DLM = 0x00 and DLD = 0x00) upon reset. Therefore, the BRG must be
programmed during initialization to the operating data rate. The DLL and DLM registers provide the integer part
of the divisor and the DLD register provides the fractional part of the divisor. Only the four lower bits of the DLD
are implemented and they are used to select a value from 0 (for setting 0000) to 0.9375 or 15/16 (for setting
1111). Programming the Baud Rate Generator Registers DLL, DLM and DLD provides the capability for
selecting the operating data rate. Table 5 shows the standard data rates available with a 24MHz crystal or
external clock at 16X clock rate. If the pre-scaler is used (MCR bit-7 = 1), the output data rate will be 4 times
less than that shown in Table 5. At 8X sampling rate, these data rates would double. Also, when using 8X
sampling mode, please note that the bit-time will have a jitter (+/- 1/16) whenever the DLD is non-zero and is
an odd number. When using a non-standard data rate crystal or external clock, the divisor value can be
calculated with the following equation(s):
Required Divisor (decimal)=(XTAL1 clock frequency / prescaler) /(serial data rate x 16), with 16X mode DLD[5:4] = ’00’
Required Divisor (decimal) = (XTAL1 clock frequency / prescaler / (serial data rate x 8), with 8X mode DLD[5:4] = ’01’
Required Divisor (decimal) = (XTAL1 clock frequency / prescaler / (serial data rate x 4), with 4X mode DLD[5:4] = ’10’
ROUND( (Required Divisor - TRUNC(Required Divisor) )*16)/16 + TRUNC(Required Divisor), where
DLM = TRUNC(Required Divisor) >> 8
DLL = TRUNC(Required Divisor) & 0xFF
DLD = ROUND( (Required Divisor-TRUNC(Required Divisor) )*16)
The closest divisor that is obtainable in the V2552 can be calculated using the following formula:
In the formulas above, please note that:
TRUNC (N) = Integer Part of N. For example, TRUNC (5.6) = 5.
ROUND (N) = N rounded towards the closest integer. For example, ROUND (7.3) = 7 and ROUND (9.9) = 10.
A >> B indicates right shifting the value ’A’ by ’B’ number of bits. For example, 0x78A3 >> 8 = 0x0078.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| XR16V2650 | 制造商:EXAR 制造商全称:EXAR 功能描述:HIGH PERFORMANCE DUART WITH 32-BYTE FIFO |
| XR16V2650_07 | 制造商:EXAR 制造商全称:EXAR 功能描述:HIGH PERFORMANCE DUART WITH 32-BYTE FIFO |
| XR16V2650IL | 制造商:Rochester Electronics LLC 功能描述: 制造商:Exar Corporation 功能描述: |
| XR16V2650IL-0B-EB | 功能描述:UART 接口集成电路 Supports V2650 32pin QFN, 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 |
| XR16V2650IL32 | 制造商:EXAR 制造商全称:EXAR 功能描述:HIGH PERFORMANCE DUART WITH 32-BYTE FIFO |
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