Glitch-free self-adaptive clock switching method for UART (Universal Asynchronous Receiver Transmitter) interface chip

Abstract

The invention discloses a glitch-free self-adaptive clock switching method for a UART (Universal Asynchronous Receiver Transmitter) interface chip. The glitch-free self-adaptive clock switching method for the UART interface chip comprises the flowing steps of (1) obtaining a next working state, namely, inputting the clock frequency and the baud rate of the UART interface chip through a self-adaptive clock switching module according to configuration information which is wrote in through a CPU (Central Processing Unit) in a parallel mode; (2) calculating the UART interface chip required mclk frequency; (3) comparing the required mclk frequency with clkin frequency, calculating the double frequency and opening a frequency doubler when the required mclk frequency is higher than the clkin frequency and closing the frequency doubler when the required mclk frequency is lower than the clkin frequency; (4) switching the chip mclk according to opening and closing of the frequency doubler. The UART interface chip comprises the self-adaptive clock switching module which is connected with a chip mclk. According to the glitch-free self-adaptive clock switching method for the UART interface chip, clock strategies of the chip is automatically adjusted and the purpose of optimizing power consumption is achieved according to a current working state of the UART interface chip and the next working state which is wrote in through the CPU.

Description

technical field [0001] The invention relates to a clock switching method of a UART interface chip. Background technique [0002] Data transmission between the host computer and external devices includes parallel transmission and serial transmission, among which parallel transmission is used for short distance and fast speed occasions, and serial transmission is usually used for long distance and low speed requirements. transmission. Such as figure 1 As shown, the UART (Universal Asynchronous Transceiver) interface chip is often used between the CPU and the serial device for parallel-to-serial port conversion: the UART interface chip converts the data written in parallel by the CPU into a serial port protocol, according to the preset frame format and waveform The baud rate is sent to the serial device; and the received serial data is stored in the internal cache for parallel reading by the CPU. [0003] Most UART interface chips can work at multiple baud rates (transmissio...

AI Technical Summary

Problems solved by technology

However, due to the existence of the internal clock multiplier of the UART interface chip, the optimization of the power consumption of the UART interface chip cannot be achieved only by adjusting the baud rate by frequency division.

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