Drinking tea is a hobby of many people, and there is also a lot of attention to making tea. Nowadays, the tea electronic scale has become a part of the tea making process. Today, let’s talk about the design of the tea electronic scale.
The tea electronic scale is an electronic scale dedicated to weighing tea. It has functions such as intelligent weighing and timing. It can accurately digitize and quantify the process of making tea by feeling in the past, so that people can find their favorite taste faster. . Under the condition that the drinking volume remains the same, controlling the amount of tea and changing the brewing time can make people get the desired taste and tea drinking standard.
The tea electronic scale solution is composed of sensors, ADC chips, and MCU chips. The design of the solution requires the cooperation of various components to ensure that the tea electronic scale solution can achieve the functions we envisage. Weighing, measuring, and pressure sensors are indispensable, and ADC chips that convert analog signals into digital information are indispensable, but to ensure that they can perform their respective functional areas before, MCU is the core and most important. So you see, the mutual cooperation and support between them is just like the organs of our human body, and the instructions issued will be executed by various functional areas, so as to ensure normal work.
The ADC chip CS1239 of the tea electronic scale solution has a built-in ADC signal chain, a Sigma-delta ADC and a digital filter Digital Filter; among them, the ADC signal chain includes input MUXP/MUXN, programmable low-noise gain amplifier (PGA); MUXP/MUXN Each has 8 input channels, including 5 external analog input channels and 3 internal input channels; after MUXP/MUXN, there is a level shift module LVSHIFT, which can shift the input signal near the ground rail and send it to PGA; in addition, CS1239
also With adjustable current source IDAC1/0, you can adjust the common-mode voltage of the input signal or compensate the offset voltage. The PGA and ADC have various gain options, and the digital filter can be configured for various output rates.
The MCU of the tea electronic scale solution is CSU14P86, a high-performance RISC MCU. It is an 8-bit single-chip MCU with built-in 4K*16-bit one-time programmable memory (OTP ROM) and 256-byte data memory (SRAM). Only 39 A single-word instruction and 8-level storage stack; internal 16MHz oscillator, external 32768Hz crystal oscillator (RTC), 4MHz~16MHz crystal oscillator.
Its specific functional parameters are as follows:
Analog characteristics Analog-to
-digital converter (ADC)
1 channel fully differential analog input
24-bit resolution
Internally integrated programmable gain amplifier
ADC output rate 30Hz~3.9KHz
with charge pump (2.6V 2.8V 3.0 V 3.2 V)
with voltage regulator for sensor and modulator
Built-in temperature sensor
Features of Dedicated Microcontroller
Power-On Reset (POR) Power-
on Reset Delay Timer (39ms)
with Low Voltage Reset (LVR)
Timer
8-bit programmable prescaler 8-bit timing counter
Extended watchdog timer (WDT)
4×14 LCD drive
Internal crystal oscillator or WDT crystal oscillator can be selected as the clock source
Two different LCD drive waveforms can be
selected Select different bias voltage generation methods
2 external interrupts
Low voltage detection (LVD) pin
Built-in low voltage programming control circuit, minimum 2.5V can be self-programming
Low power consumption characteristics
MCU operating current
normal mode 500uA@500KHz (operating voltage 3.3V)
current in sleep mode is less than 2μA
CMOS Technology
Voltage Operating Range
DVDD 2.4V~3.6V
AVDD 2.4V~3.6V
Package
SOP28
SSOP24
QFN32