This project demonstrates how to interface the MCP3208 12-bit, 8-channel analog-to-digital converter (ADC) with an STM32F103C6 microcontroller using the SPI protocol. The MCP3208 provides high-precision 12-bit resolution with flexible input configuration options, supporting both eight single-ended inputs and four pseudo-differential input pairs. The device operates from 2.7V to 5.5V and communicates via a straightforward SPI interface, achieving sampling rates up to 100 ksps. This integration enables precise multi-channel data acquisition for applications such as sensor interfaces, process control, and battery-operated systems, with real-time data output via UART and full Proteus simulation support.
STM32CubeMX Setup- MCU Selection: STM32F103C6
- Clock Configuration: 8 MHz HSI
- SPI1 Configuration:
- Mode: Full-Duplex Master
- Prescaler: 16 (500 kHz SPI clock for MCP3208 compatibility)
- CPOL: Low, CPHA: 1 Edge
- GPIO Configuration:
- PA4 configured as Output Push-Pull (Chip Select/Shutdown for MCP3208)
- UART1 Configuration:
- Baud Rate: 115200
- Word Length: 8 bits
- Parity: None
- Stop Bits: 1
- Generate initialization code in STM32CubeIDE.
Key Functions
- MCP3208 Structure & Initialization
- MCP3208_HandleTypeDef
- Structure containing SPI handler and CS GPIO configuration for device management.
- void MCP3208_Init(MCP3208_HandleTypeDef* hmcp3208);
- Initializes the MCP3208 ADC by configuring SPI interface and CS GPIO pin.
- Single-Ended Input Measurement
- uint16_t MCP3208_AnalogRead(MCP3208_HandleTypeDef* hmcp3208, uint8_t channel);
- Reads single-ended analog value from specified channel (0-7) and returns 12-bit result.
- Differential Input Measurement
- int16_t MCP3208_AnalogReadDif(MCP3208_HandleTypeDef* hmcp3208, uint8_t pair);
- Reads differential analog input from specified channel pair and returns signed 12-bit result.
- Main Loop Logic
while (1)
{
// Read single-ended value from channel 0
uint16_t adc_value = MCP3208_AnalogRead(&hmcp3208, 0);
// Send data via UART
printf("CH0 Value: %d\r\n", adc_value);
HAL_Delay(500);
}Required Components:
- STM32F103C6 microcontroller
- MCP3208 12-bit ADC
- POT-HG (Potentiometer)
- RES (Resistor, 10kΩ for reference circuits)
- Virtual Terminal (UART)
Connections:
- SPI1: PB3 (SCK) → MCP3208 CLK, PB4 (MISO) → MCP3208 DOUT, PB5 (MOSI) → MCP3208 DIN
- Chip Select: PA4 → MCP3208 CS/SHDN
- Analog Input: Potentiometer output → MCP3208 CH0
- Power: MCP3208 VDD → 3.3V, VREF → 3.3V, AGND & DGND → GND
- UART1: PA9 (TX) → Virtual Terminal RX
Steps:
- Load the.hex file compiled from CubeIDE.
- Run the simulation.
- Adjust the potentiometer to vary the analog voltage on channel 0 (0V-3.3V).
- Observe the real-time 12-bit ADC values (0-4095) on the Virtual Terminal.
If you have any questions or suggestions don't hesitate to leave a comment below
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