axoulc / ad7799-stm32

STM32 library for the 24bits ADC Analog Device AD7799

Welcome to AD7799-STM32 👋

STM32 library for the 24bits ADC Analog Device AD7799

Default Configuration (on startup or after reset)

• Conversion mode : Continous
• PGA Gain : 128
• Channel : AIN1P-AIN1M
• Polarity : Bipolar
• Sample Rate : 16.7 Hz

What is not implemented ?

• Continous Conversion

SPI Configuration

• Data Size : 8bits
• First Bit : MSB First
• Baud Rate : up to 5 MBits
• Clock Polarity : High (Mode 3)
• Clock Phase : 2 Edge (Mode 3)

Usage

#include "AD7799.h"

AD7799 adc;

int main(void) {
	adc.adcspi = &hspi3; //Your SPI Handler
	adc.CSPort = ADC_CS_GPIO_Port; // Your CS Port
	adc.CSPin = ADC_CS_Pin; // Your CS Pin
	adc.vref = 3.0; // Your Voltage reference
	
	AD7799_Reset(&adc);
	if (AD7799_Init(&adc) != HAL_OK) {
	    Error_Handler();
	}
	AD7799_SetGain(&adc, AD7799_GAIN_64);
	AD7799_SetPolarity(&adc, AD7799_UNIPOLAR);
	
	if (AD7799_SingleConversion(&adc) != HAL_OK) {
	    Error_Handler();
	}
	printf("Raw value : %ld - Voltage Value : %f\r\n", adc.rawConversion, adc.voltConversion);
}

Author

👤 Axel Chabot

• Github: @axoulc

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📝 License

Copyright © 2021 Axel Chabot.
This project is MIT licensed.

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ad7799-stm32's Issues

Possible bug in AD7799_SingleConversion?

Axel

First I'd like to say it's a great library and has got me up and running quickly with the AD7799.

I was having a few issues with AD7799_SingleConversion timing out. I thing you may have missed out some brackets in the line:

if (HAL_GetTick() - startTime
> (uint32_t) 1.5 * settle_time_ms[(uint8_t) ad7799->rate]) {

I think basically you are casting 1.5 to a uint32_t and so multiplying the settle time by 1 instead of 1.5. Looks like you need this instead:

(uint32_t) (1.5 * settle_time_ms[(uint8_t) ad7799->rate]))

This gave me the expected 180ms timeout for the value 120ms in the array.

Regards
Alan