4-Layer PCB Designs
Budget: ₹1,500 – ₹12,500 INR
Microcontroller
EFM32TG840F32-QFN64: ARM Cortex-M3, 32 KB Flash, 4 KB SRAM, QFN64 package.
Analog Front-End
LMP7721 buffers for ISE and reference electrodes, routed to ADC0_CH0 and CH1.
Temperature Sensor
DS18B20 or analog sensor connected to GPIO or ADC.
EEPROM
I2C EEPROM (e.g., 24C02) to store calibration data.
Modbus Communication
ADM2483 RS-485 transceiver, USART1 for Modbus RTU.
Power Supply
12V input → Isolated DC-DC → 5V → 3.3V LDO.
Modbus Register Map
Registers for raw ADC, mV diff, temp, calibration.
Calibration Logic
EFM32TG840F32-QFN64: ARM Cortex-M3, 32 KB Flash, 4 KB SRAM, QFN64 package.
Analog Front-End
LMP7721 buffers for ISE and reference electrodes, routed to ADC0_CH0 and CH1.
Temperature Sensor
DS18B20 or analog sensor connected to GPIO or ADC.
EEPROM
I2C EEPROM (e.g., 24C02) to store calibration data.
Modbus Communication
ADM2483 RS-485 transceiver, USART1 for Modbus RTU.
Power Supply
12V input → Isolated DC-DC → 5V → 3.3V LDO.
Modbus Register Map
Registers for raw ADC, mV diff, temp, calibration.
Calibration Logic
Related categories:
Electronics
Microcontroller
Electrical Engineering
PCB Layout
ARM
Embedded Systems
I2C
Analog Electronics