-USART. Serial I/O – Programmable Communication Interface. Data Communications. Data communications refers to the ability of one computer to. USART The is a USART (Universal Synchronous Asynchronous Receiver Transmitter) for serial data communication. Interrupt Structure of . The modem control unit handles the modem handshake signals to coordinate the communication between modem and transmit control unit.
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Intel – Wikipedia
That is, the writing of a control word after resetting will be recognized as a “mode instruction. Mode instruction is used for setting the function of the This is a clock input 821 which determines the transfer speed of transmitted data. Data is transmitable if the terminal is at low level. In such a case, an overrun error flag status word will be set. Table 1 shows the operation between a CPU and the device.
As a peripheral device of a microcomputer system, the receives parallel data from the CPU and transmits serial data after conversion. This is the “active low” input terminal which receives a signal for reading receive data and status words from the The bit configuration of status word is shown in Fig.
It is possible to see the internal status of the by reading a status word. The bit configuration of mode instruction is shown in Figures 2 and 3.
A “High” on this input forces the into “reset status. A “High” on this input forces the to start receiving data characters. As the transmitter is disabled by setting CTS “High” or command, data written before disable will be sent out.
This is the “active low” input terminal which receives a signal for writing transmit data and control words from the CPU into the Command is arfhitecture for setting the operation of the Even if a data is written after disable, that data is not sent out and TXE will be “High”.
The input status of the terminal can be recognized by the CPU reading status words.
In “asynchronous mode,” it is possible to select the baud rate factor by mode instruction. The terminal will be reset, if RXD is at high level. In “asynchronous arcitecture, it is possible to select the baud rate factor by mode instruction.
In “external synchronous mode, “this is an input terminal. If a status word is read, the terminal will be reset. It is possible to set the status RTS by a command. Mode instruction will be in “wait for write” at either internal reset or external reset.
It is possible to write a command whenever necessary after writing a mode instruction and sync characters. The functional configuration is programed by software. This is an input terminal which receives a signal for selecting data or command words and status words when the is accessed by the CPU.
CLK signal is used to generate internal device timing. This is an output terminal which indicates that the is ready to accept a transmitted data character. If sync characters were written, a function will be set because the writing of sync characters constitutes part of mode instruction. In “synchronous mode,” the baud rate will be the same as the frequency of TXC.
Achitecture “synchronous mode,” the baud rate is the same as the frequency of RXC. It is also possible to set the device in “break status” low level by a command. In “internal synchronous mode. This is an output terminal which indicates that the has transmitted all the characters and had no data character.
UNIVERSAL SYNCHRONOUS ASYNCHRONOUS RECEIVER TRANSMITTER
This is a terminal whose function changes according to mode. This is a terminal which indicates that the contains a character that is ready to READ.
The terminal controls data transmission if the device is set in “TX Enable” status by a command.
After Reset is active, the terminal will be output at low level. Ueart is possible to set the status of DTR by a command. This is bidirectional data bus which receive control words and transmits data from the CPU and sends status words and received data to CPU. In “asynchronous mode,” this is an output terminal which generates “high level”output upon the detection of a “break” character if receiver data contains a “low-level” space between the stop bits of two continuous characters.
After the transmitter is enabled, it sent out. This is a clock input signal which determines the transfer speed of received data. This device also receives serial data from the outside and transmits parallel data to the CPU after conversion.