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參數(shù)資料
| 型號： | XR16C850IP |
| 英文描述： | UART|CMOS|DIP|40PIN|PLASTIC |
| 中文描述： | 異步|的CMOS |雙酯| 40PIN |塑料 |
| 文件頁數(shù)： | 9/49頁 |
| 文件大小： | 690K |
| 代理商： | XR16C850IP |
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XR16C854/XR16C854D
3.3V AND 5V QUAD UART WITH 128-BYTE FIFO
REV. 2.0
9
1.0
The XR16C854 (854) integrates the functions of 4 en-
hanced 16C550 Universal Asynchrounous Receiver
and Transmitter (UART). Each UART is independently
controlled having its own set of device configuration
registers. The configuration registers set is 16550
UART compatible for control, status and data transfer.
Additionally, each UART channel has 128-bytes of
transmit and receive FIFOs, automatic RTS/CTS
hardware flow control with hysteresis control, auto-
matic Xon/Xoff and special character software flow
control, programmable transmit and receive FIFO
trigger levels, FIFO level counters, infrared encoder
and decoder (IrDA ver 1.0), programmable baud rate
generator with a prescaler of divide by 1 or 4, and da-
ta rate up to 2 Mbps. The XR16C854 can operate at
3.3 or 5 volts. The 854 is fabricated with an advanced
CMOS process.
Enhanced FIFO
The 854 QUART provides a solution that supports
128 bytes of transmit and receive FIFO memory, in-
stead of 64 bytes provided in the ST16C654 and 16
bytes in the ST16C554, or one byte in the
ST16C454. The 854 is designed to work with high
performance data communication systems, that re-
quire fast data processing time. Increased perfor-
mance is realized in the 854 by the larger transmit
and receive FIFOs, FIFO trigger level control, FIFO
level counters and automatic flow control mecha-
nism. This allows the external processor to handle
more networking tasks within a given time. For exam-
ple, the ST16C554 with a 16 byte FIFO, unloads 16
bytes of receive data in 1.53 ms (This example uses a
character length of 11 bits, including start/stop bits at
115.2Kbps). This means the external CPU will have
to service the receive FIFO at 1.53 ms intervals. How-
ever with the 128 byte FIFO in the 854, the data buffer
will not require unloading/loading for 12.2 ms. This in-
creases the service interval giving the external CPU
additional time for other applications and reducing the
overall UART interrupt servicing time. In addition, the
programmable FIFO level trigger interrupt and auto-
matic hardware/software flow control is uniquely pro-
vided for maximum data throughput performance es-
pecially when operating in a multi-channel system.
The combination of the above greatly reduces the
CPU’s bandwidth requirement, increases perfor-
mance, and reduces power consumption.
Data Rate
The 854 is capable of operation up to 2 Mbps at 5V
with 16x internal sampling clock rate. The device can
operate with a crystal oscillator of up to 24 MHz crys-
tal on pins XTAL1 and XTAL2, or external clock
PRODUCT DESCRIPTION
source of 32 MHz on XTAL1 pin. With a typical crystal
of 14.74128 MHz and through a software option, the
user can set the prescaler bit for data rates of up to
921.6 kbps.
Enhanced Features
The rich feature set of the 854 is available through the
internal registers. Automatic hardware/software flow
control, selectable transmit and receive FIFO trigger
levels, selectable baud rates, infrared encoder/decod-
er interface, modem interface controls, and a sleep
mode are all standard features. MCR bit-5 provides a
facility for turning off (Xon) software flow control with
any incoming (RX) character. In the 16 mode INT-
SEL and MCR bit-3 can be configured to provide a
software controlled or continuous interrupt capability.
Due to pin limitations for the 64 pin 854 this feature is
offered by two different TQFP packages. The
XR16C854DCV operates in the continuous interrupt
enable mode by internally bonding INTSEL to VCC.
The XR16C854CV operates in conjunction with MCR
bit-3 by internally bonding INTSEL to GND.
The 68 and 100 pin XR16C854 packages offer a
clock prescaler select pin to allow system/board de-
signers to preset the default baud rate table on power
up. The CLKSEL pin selects the div-by-1 or div-by-4
prescaler for the baud rate generator. It can then be
overridden following initializatioin by MCR bit-7.
The 100 pin packages offer several other enhanced
features. These features include a CHCCLK clock in-
put, FSTAT register and separate IrDA TX outputs.
The CHCCLK must be connected to the XTAL2 pin for
normal operation or to external MIDI (Music Instru-
ment Digital Interface) oscillator for MIDI applications.
A separate register (FSTAT) is provided for monitoring
the real time status of the FIFO signals TXRDY# and
RXRDY# for each of the four UART channels (A-D).
This reduces polling time involved in accessing indi-
vidual channels. The 100 pin QFP package also of-
fers four separate IrDA (Infrared Data Association
Standard) TX outputs for Infrared applications. These
outputs are provided in addition to the standard asyn-
chronous modem data outputs.
2.0
2.1
The CPU interface is 8 data bits wide with 3 address
lines and control signals to execute data bus read and
write transactions. The 854 data interface supports
the Intel compatible types of CPUs and it is compati-
ble to the industry standard 16C550 UART. No clock
(oscillator nor external clock) is required to operate a
data bus transaction. Each bus cycle is asynchronous
using CS# A-D, IOR# and IOW# or CS#, R/W#, A4
FUNCTIONAL DESCRIPTIONS
CPU I
NTERFACE
相關(guān)PDF資料 |
PDF描述 |
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| XR16C850IQ | UART|CMOS|QFP|52PIN|PLASTIC |
| XR17C158CV | UART |
| XR17C158IV | UART |
| XR215CP | IC-PHASE LOCKED LOOP |
| XR215 | Monolithic Phase Locked Loop |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| XR16C850IQ | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:UART|CMOS|QFP|52PIN|PLASTIC |
| XR16C854 | 制造商:EXAR 制造商全稱:EXAR 功能描述:并轉(zhuǎn)串4串口擴展芯片 |
| XR16C854CJ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Exar Corporation 功能描述: |
| XR16C854CJ-0A-EVB | 功能描述:UART 接口集成電路 Supports C854 68 ld PLCC, ISA Interface RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 數(shù)據(jù)速率:3 Mbps 電源電壓-最大:3.6 V 電源電壓-最小:2.7 V 電源電流:20 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:LQFP-48 封裝:Reel |
| XR16C854CJ-F | 功能描述:UART 接口集成電路 UART RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 數(shù)據(jù)速率:3 Mbps 電源電壓-最大:3.6 V 電源電壓-最小:2.7 V 電源電流:20 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:LQFP-48 封裝:Reel |
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