How to design a minimal system?

manhuami2007

How to design a minimal system? [Copy link]

When designing a circuit board, we usually start with a minimum system of an MCU. So what parts should a minimum system include? What are the precautions?

A minimum system should include the following parts to be able to be used normally: Power supply, reset circuit, clock, BOOT circuit, debug interface, firmware download interface Power supply The power supply should be considered in two parts, the input part and the output part. The input part is the power supply introduced into the minimum system, and the output part is the power supply connected to the MCU. The input part needs to consider

• The type of hardware interface, such as the input voltage value of the USB interface

The output part needs to consider

• The type of power supply required by the MCU,
• Merge or cut the power supply circuit according to the function.
• Determine the capacitance of the decoupling capacitor corresponding to each power supply

First, we need to know the type of power supply required by the MCU, which usually includes: analog power supply, digital power supply, MCU internal voltage regulator, backup power supply, etc. However, for different functions, some power supplies do not need to be provided separately, so the power supply circuits need to be merged and tailored. For example, if the design does not require a backup function, a digital power supply can be used instead of a backup power supply. If the ADC and DAC functions of the MCU are not used, the digital power supply can be merged with the analog power supply. Reset circuit

• Is a reset button required
• Is it necessary to connect capacitors or resistors externally

Clock

• Is an external crystal oscillator required
• Determine the frequency value of the external crystal oscillator

For some MCUs, they contain low-precision crystal oscillators. When the circuit does not require high time accuracy, an external crystal oscillator can be used. BOOT mode Determine the external circuit of the BOOT pin Debug interface There are many ways to debug, such as JTAG interface, SWD interface, or use the serial port to print debugging information. Firmware download interface Determine which interface to use to download the firmware, such as using the serial port to download, or you can use the debug interface to download. This content is originally created by EEWORLD forum user manhuami2007. If you need to reprint or use it for commercial purposes, you must obtain the author's consent and indicate the source

cslwp

Study and learn! Good article!

youmcu

I made a pic a few years ago

qwqwqw2088

The official development board is generally the smallest system, you can refer to

tiankai001

Many microcontrollers do not have BOOT circuits.

llllllllllll

For a microcontroller with an internal crystal oscillator, a resistor-capacitor reset is enough to lead out the pin.