参数资料
| 型号： | MAX3140EEI+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 10/36页 |
| 文件大小： | 0K |
| 描述： | IC UART W/RS485 28-QSOP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 50 |
| 特点： | 收发器 |
| FIFO's： | 8 字节 |
| 规程： | RS232，RS485 |
| 电源电压： | 4.75 V ~ 5.25 V |
| 带IrDA 编码器/解码器： | 是 |
| 带故障启动位检测功能： | 是 |
| 带CMOS： | 是 |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-QSOP |
| 供应商设备封装： | 28-QSOP |
| 包装： | 管件 |
第1页第2页第3页第4页第5页第6页第7页第8页第9页当前第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页
MAX3140
SPI/MICROWIRE-Compatible UART with Integrated
True Fail-Safe RS-485/RS-422 Transceivers
18
______________________________________________________________________________________
Table 1. Bit Descriptions (continued)
POR
STATE
DESCRIPTION
BIT
TYPE
BIT
NAME
0
SHDNi
write
Software-Shutdown Bit. Enter software shutdown with a WRITE CONFIGURATION where
SHDNi = 1. Software shutdown takes effect after CS goes high, and causes the oscillator to
stop as soon as the transmitter becomes idle. Software shutdown also clears R, T, RA/FE,
D0r–D7r, D0t–D7t, Pr, Pt, and all data in the receive FIFO. RTS and CTS can be read and
updated while in shutdown. Exit software shutdown with a WRITE CONFIGURATION where
SHDNi = 0. The oscillator restarts typically within 50ms of CS going high. RTS and CTS are
unaffected. Refer to the
Pin Description for hardware shutdown (SHDN input).
0
SHDNo
read
Shutdown Read-Back Bit. The READ CONFIGURATION register outputs SHDNo = 1 when the
UART is in shutdown. Note that this bit is not sent until the current byte in the transmitter is
sent (T = 1). This tells the processor when it may shut down the RS-485/RS-422 driver. This bit
is also set immediately when the device is shut down through the SHDN pin.
0
RA/FE
read
Receiver-Activity/Framing-Error Bit. In shutdown mode, this is the RA bit. In normal operation,
this is the FE bit. In shutdown mode, a transition on RX sets RA = 1. In normal mode, a fram-
ing error sets FE = 1. A framing error occurs if a zero is received when the first stop bit is
expected. FE is set when a framing error occurs, and cleared upon receipt of the next proper-
ly framed character independent of the FIFO being enabled. When the device wakes up, it is
likely that a framing error will occur. This error is cleared with a WRITE CONFIGURATION. The
FE bit is not cleared on a READ DATA operation. When an FE is encountered, the UART
resets itself to the state where it is looking for a start bit.
0
ST
write
Transmit-Stop Bit. One stop bit will be transmitted when ST = 0. Two stop bits will be transmit-
ted when ST = 1. The receiver only requires one stop bit.
0
ST
read
Reads the value of the ST bit.
0
TM
write
Mask for T Bit. IRQ is asserted if TM = 1 and T = 1 (Table 7).
0
TM
read
Reads the value of the TM bit (Table 7).
1
T
read
Transmit-Buffer-Empty Flag. T = 1 means that the transmit buffer is empty and ready to
accept another data word.
0
TE
write
Transmit-Enable Bit. If TE = 1, then only the RTS pin is updated on CS’s rising edge. The con-
tents of RTS, Pt, and D0t–D7t transmit on CS’s rising edge when TE = 0.
Notice to High-Level Programmers
The MAX3140 follows the SPI convention of providing a
bidirectional data path for writes and reads. Whenever
the data is written, data is also read back. This speeds
operation over the SPI bus, as required, when operat-
ing at high baud rates. In most high-level languages,
like C, there are commands for writing and reading
stream I/O devices like the console or serial port. In C
specifically, there is a “PUTCHAR” command that
transmits a character and a “GETCHAR” command that
receives a character. Implementing direct write and
read commands in C with no underlying driver code
causes an intended PUTCHAR command to become a
PUTGETCHAR command. These C commands assume
that they’ll receive some form of BIOS-level support.
The proper way to implement these commands is to
use driver code—usually in the form of an assembly
language interrupt service routine and a callable rou-
tine used by high-level routines. This driver handles the
interrupts and manages the receive and transmit
buffers for the MAX3140. When a PUTCHAR executes,
this driver is called and it safely buffers any characters
received when the current character is transmitted.
Likewise, when a GETCHAR executes, it checks its own
receive buffer before getting data from the MAX3140.
See the C-language outline of a MAX3140 software dri-
ver in Listing 1.
相关PDF资料 |
PDF描述 |
|---|---|
| MAX3157CAI | IC TXRX RS485/422 250KBPS 28SSOP |
| MAX3160CAP | IC TXRX RS485/422 10MBPS 20SSOP |
| MAX3160EEAP+T | IC TXRX RS232/485/422 20SSOP |
| MAX3170CAI | IC TXRX CLOCK/DATA 3.3V 28-SSOP |
| MAX3171CAI | IC TXRX MULTIPROTOCL 3.3V 28SSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX3140EEI+ | 功能描述:UART 接口集成电路 SPI/uWire Compatible 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 |
| MAX3140EEI+T | 功能描述:UART 接口集成电路 SPI/uWire Compatible 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 |
| MAX3140EEI-T | 功能描述:UART 接口集成电路 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 |
| MAX3147NC SPL | 制造商:Toshiba America Electronic Components 功能描述:NORTEL HDD - Bulk |
| MAX314C/D | 功能描述:模拟开关 IC 10Ohm Quad SPST CMOS Analog Switches RoHS:否 制造商:Texas Instruments 开关数量:2 开关配置:SPDT 开启电阻（最大值）:0.1 Ohms 切换电压（最大）: 开启时间（最大值）: 关闭时间（最大值）: 工作电源电压:2.7 V to 4.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:DSBGA-16 |
发布紧急采购，3分钟左右您将得到回复。