【RA】PWM fan controller professional version +382816A

Project Introduction

Based on Renesas RA MCU, design a controller for computer 4Pin PWM fan. ~~~~

Preliminary preparation

The speed control of computer fans is generally PWM and DC. PWM control requires 4 wires, which are 12V, GND, speed detection, and PWM signal.

I used an oscilloscope to measure the motherboard’s PWM signal to be 5V-23.44kHz, and the speed detection signal to be

Power supply part: The 12V to 5V part is FP6115DR. You can use the IC that you removed from the material board directly; the 5V to 3.3V part is 1117-3.3.

Main control part: R7FA2E1A72DFL

LED part: 74HC595 controls 8 LEDs. It is also a disassembled part and occupies 3 IOs.

PWM part: Use NTMFS4C10N MOS tube for level conversion, remove it from the old surface, which is a bit overkill.

Software part: developed using Keil, refer to the official PWM routine.

The chip clock is 48M, to make the PWM frequency 24kHz, the counter value should be set to 2000, on line 28.

The range of ndt is 0~100, 32 lines is a negative clock period, and the calculated value is 2000~0.

Behaviors 55~58 control the PWM duty cycle, changing from 0 to 100 and then to 0 in a cycle.

Demo video: https://www.bilibili.com/video/BV1vY411c7cz/

There is a problem

1. USB 5V pin network error (fixed)

2. PWM fan socket line sequence error (corrected)