Micro control unit (MCU) startup mode selecting circuit and MCU code updating method based on circuit

Abstract

The invention discloses a micro control unit (MCU) startup mode selecting circuit and an MCU code updating method based on the circuit. The circuit comprises a circuit consisting of a power supply, a single-pole switch, a pull-up resistor and a first pull-down resistor, and also comprises a capacitor, a diode and a second pull-down resistor, wherein one end of the first pull-down resistor is connected with one end of the single-pole switch; the other end of the first pull-down resistor is grounded; the other end of the single-pole switch is connected with one end of the pull-up resistor; the other end of the pull-up resistor is connected with the power supply; one end of the second pull-down resistor is grounded; the other end of the second pull-down resistor is connected with the positive electrode of the diode and MCU general input / output pins; one end of the capacitor is grounded; the other end of the capacitor is connected with the negative electrode of the diode, the other end of the single-pole switch, one end of the pull-up resistor and an MCU startup mode selecting pin. The circuit can finish MCU code updating without disassembling and assembling a machine and toggling a switch, and the time is shortened to be only the code burning time, so that the MCU code updating is simple, convenient and easy to operate.

Description

Technical field [0001] The present invention relates to the field of micro control unit (Micro Control Unit, MCU) startup mode, in particular to an MCU startup mode selection circuit and an MCU code update method based on the circuit. Background technique [0002] The startup mode of the MCU is divided into normal working mode and programming mode. The programming mode is used for programming and updating the MCU code. When the MCU starts, it will detect the potential of the startup mode selection pin to determine which mode to enter. If it is detected that the startup mode selection pin is at a low level, the MCU enters the normal working mode, and if it is detected that the startup mode selection pin is at a high level, the MCU enters the programming mode. Therefore, it is necessary to give a potential value to the MCU startup mode selection pin before starting the MCU. [0003] The startup mode selection circuit in the prior art is a circuit composed of a single-pole switch, a...

AI Technical Summary

Problems solved by technology

[0004] This method has the following defects: first, frequent disassembly and assembly of the machine may easily cause disassembly and assembly wear of the MCU; second, professional disassembly and assembly technology is required to complete the disassembly and assembly of the MCU; third, MCU code updates The time is long, the MCU code update time includes not only the code burning time, but also the time spent on disassembling and assembling the machine

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