UNIVERSAL SYNCHRONOUS AND ASYNCHRONOUS RECEIVER TRANSMITTER-8251
The 8251 is a USART (Universal Synchronous Asynchronous Receiver Transmitter) for serial data communication. As a peripheral device of a microcomputer system, the 8251 receives parallel data from the CPU and transmits serial data after conversion. This device also receives serial data from the outside and transmits parallel data to the CPU after conversion.
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Block diagram of the 8251 USART (Universal Synchronous Asynchronous Receiver Transmitter)
The 8251 functional configuration is programed by software. Operation between the 8251 and a CPU is executed by program control. Table 1 shows the operation between a CPU and the device.
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Table 1 Operation between a CPU and 8251