Guoxin Sichen | Application of domestic touch button series MCU TM56M1531 in smart desk lamp

With the rapid development of electronic products, household appliances are becoming more and more intelligent. Intelligent household appliances all have a common feature, which is that they all use MCU as the central control unit. Compared with ordinary household appliances, intelligent household appliances combined with MCU are more convenient to use, safer and more reliable, and more efficient.

The touch desk lamp solution introduced in this article adopts touch dimming control, which is currently widely used in touch control of LEDs such as desk lamps and bedside night lights. It has a dimming memory function, and the default working mode is the last time it was turned off after being turned on. The touch lamp touch control solution can be powered by home appliances and lithium batteries, with low standby power consumption and stable performance. The main control chip of the touch desk lamp is TM56M1531, which is a Hispeed 8-bit RISC TM56 series MCU. The main features are as follows:

•ROM: 2Kx16-bit Flash program memory

•RAM: 256x8 bits

•System clock type selection:

Internal RC fast clock: 16MHz (FIRC)

Internal RC slow clock: (SIRC, 80KHz@4V)

• 2 independent timers

Timer0 - 8-bit timer divided by 1~256 prescale option with auto-reload/counter/interrupt/stop functions

Timer1 - 8-bit timer divided by 1~256 prescale option with auto-reload/interrupt/stop function

• Wake-up Timer (WKT)

Clocked by built-in RC oscillator with 4 adjustable interrupt times

-12ms/25ms/50ms/100ms@4V

• Touch key

Two different architectures: CTK and STK

4 channel touch keys with data counter

Introduction to the touch light function based on the TM56M1531 solution:

1. When the power is first turned on, the LED light is not on.

2. Short press the touch to turn on and off the two lights respectively; when the power is not cut off, the brightness of each short press to turn off the light will be memorized and saved, and the next time you touch to turn on the light, this brightness will be used as the initial brightness.

3. Long press the touch to achieve stepless brightness adjustment of the two lights. The duty cycle of the PWM signal for the lowest brightness is 2%, and the highest brightness is 100%. When a street lamp or two street lamps are on at the same time, long press the touch to adjust the brightness of the lamp steplessly.

4. Short-press touch and long-press touch can be used at any time without interference or restriction between their functions.