參數(shù)資料
型號: MAX3140CEI
廠商: MAXIM INTEGRATED PRODUCTS INC
元件分類: 微控制器/微處理器
英文描述: 4x4 1.5 Gbps LVDS Crosspoint Switch 38-TSSOP -40 to 85
中文描述: 1 CHANNEL(S), 240K bps, SERIAL COMM CONTROLLER, PDSO28
封裝: 0.150 INCH, 0.025 INCH PITCH, QSOP-28
文件頁數(shù): 18/36頁
文件大小: 468K
代理商: MAX3140CEI
M
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.
相關(guān)PDF資料
PDF描述
MAX314LCSE 10 з, Quad, SPST, +3V Logic-Compatible Analog Switches
MAX314LCUE 10 з, Quad, SPST, +3V Logic-Compatible Analog Switches
MAX314LEPE 10 з, Quad, SPST, +3V Logic-Compatible Analog Switches
MAX314LESE 10 з, Quad, SPST, +3V Logic-Compatible Analog Switches
MAX314LEUE 10 з, Quad, SPST, +3V Logic-Compatible Analog Switches
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX3140CEI+ 功能描述:UART 接口集成電路 SPI/uWire Compatible 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
MAX3140CEI+T 功能描述:UART 接口集成電路 SPI/uWire Compatible 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
MAX3140CEI-T 功能描述:UART 接口集成電路 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
MAX3140EEI 功能描述:UART 接口集成電路 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
MAX3140EEI+ 功能描述:UART 接口集成電路 SPI/uWire Compatible 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