/**+
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  ******************************************************************************+
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  * @file    externalInterface.c+
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  * @author  heinrichs weikamp gmbh+
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  * @version V0.0.1+
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  * @date    07-Nov-2020+
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  * @brief   Interface functionality to proceed external analog signal via i2c connection+
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  *+
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  @verbatim+
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  ==============================================================================+
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                ##### stm32f4xx_hal_i2c.c modification #####+
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  ==============================================================================+
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	The LTC2942 requires an repeated start condition without stop condition+
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	for data reception.+
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+
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  @endverbatim+
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  ******************************************************************************+
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  * @attention+
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  *+
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  * <h2><center>&copy; COPYRIGHT(c) 2014 heinrichs weikamp</center></h2>+
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  *+
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  ******************************************************************************+
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  */+
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/* Includes ------------------------------------------------------------------*/+
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+
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#include <math.h>+
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#include "i2c.h"+
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#include "externalInterface.h"+
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#include "scheduler.h"+
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+
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extern SGlobal global;+
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+
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#define ADC_ANSWER_LENGTH	(5u)		/* 3424 will provide addr + 4 data bytes */+
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#define ADC_TIMEOUT			(10u)		/* conversion stuck for unknown reason => restart */+
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#define ADC_REF_VOLTAGE_MV	(2048.0f)	/* reference voltage of MPC3424*/+
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+
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#define ADC_START_CONVERSION		(0x80)+
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#define ADC_GAIN_4					(0x02)+
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#define ADC_GAIN_4_VALUE			(4.0f)+
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#define ADC_GAIN_8					(0x03)+
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#define ADC_GAIN_8_VALUE			(8.0f)+
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#define ADC_RESOLUTION_16BIT		(0x08)+
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#define ADC_RESOLUTION_16BIT_VALUE	(16u)+
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#define ADC_RESOLUTION_18BIT		(0x0C)+
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#define ADC_RESOLUTION_18BIT_VALUE	(18u)+
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+
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#define ANSWER_CONFBYTE_INDEX		(4u)+
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+
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static uint8_t activeChannel = 0;			/* channel which is in request */+
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static uint8_t recBuf[ADC_ANSWER_LENGTH];+
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static uint8_t timeoutCnt = 0;+
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static uint8_t externalInterfacePresent = 0;+
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+
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float externalChannel_mV[MAX_ADC_CHANNEL];+
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+
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+
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void externalInterface_Init(void)+
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{+
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	activeChannel = 0;+
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	timeoutCnt = 0;+
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	externalInterfacePresent = 0;+
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	if(externalInterface_StartConversion(activeChannel) == HAL_OK)+
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	{+
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		externalInterfacePresent = 1;+
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		global.deviceDataSendToMaster.hw_Info.extADC = 1;+
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	}+
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	global.deviceDataSendToMaster.hw_Info.checkADC = 1;+
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}+
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+
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+
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uint8_t externalInterface_StartConversion(uint8_t channel)+
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{+
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	uint8_t retval = 0;+
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	uint8_t confByte = 0;+
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+
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	if(channel < MAX_ADC_CHANNEL)+
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	{+
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		confByte = ADC_START_CONVERSION | ADC_RESOLUTION_16BIT | ADC_GAIN_8;+
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		confByte |= channel << 5;+
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		retval = I2C_Master_Transmit(DEVICE_EXTERNAL_ADC, &confByte, 1);+
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	}+
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	return retval;+
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}+
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+
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/* Check if conversion is done and trigger measurement of next channel */+
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uint8_t externalInterface_ReadAndSwitch()+
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{+
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	uint8_t retval = EXTERNAL_ADC_NO_DATA;+
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+
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	if(externalInterfacePresent)+
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	{+
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		if(I2C_Master_Receive(DEVICE_EXTERNAL_ADC, recBuf, ADC_ANSWER_LENGTH) == HAL_OK)+
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		{+
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			if((recBuf[ANSWER_CONFBYTE_INDEX] & ADC_START_CONVERSION) == 0)		/* !ready set => received data contains new value */+
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			{+
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				retval = activeChannel;										/* return channel number providing new data */+
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				activeChannel++;+
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				if(activeChannel == MAX_ADC_CHANNEL)+
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				{+
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					activeChannel = 0;+
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				}+
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				externalInterface_StartConversion(activeChannel);+
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				timeoutCnt = 0;+
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			}+
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			else+
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			{+
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				if(timeoutCnt++ >= ADC_TIMEOUT)+
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				{+
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					externalInterface_StartConversion(activeChannel);+
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					timeoutCnt = 0;+
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				}+
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			}+
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		}+
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	}+
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	return retval;+
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}+
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float externalInterface_CalculateADCValue(uint8_t channel)+
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{+
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	int32_t rawvalue = 0;+
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	float retValue = 0.0;+
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	if(channel < MAX_ADC_CHANNEL)+
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	{+
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+
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		rawvalue = ((recBuf[0] << 16) | (recBuf[1] << 8) | (recBuf[2]));+
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+
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		switch(recBuf[3] & 0x0C)			/* confbyte => Resolution bits*/+
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		{+
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			case ADC_RESOLUTION_16BIT:		rawvalue = rawvalue >> 8;										/* only 2 databytes received shift out confbyte*/+
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											if(rawvalue & (0x1 << (ADC_RESOLUTION_16BIT_VALUE-1)))			/* MSB set => negative number */+
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											{+
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												rawvalue |= 0xFFFF0000; 	/* set MSB for int32 */+
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											}+
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											else+
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											{+
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												rawvalue &= 0x0000FFFF;+
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											}+
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											externalChannel_mV[channel] = ADC_REF_VOLTAGE_MV * 2.0 / (float) pow(2,ADC_RESOLUTION_16BIT_VALUE);	/* calculate bit resolution */+
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				break;+
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			case ADC_RESOLUTION_18BIT:		if(rawvalue & (0x1 << (ADC_RESOLUTION_18BIT_VALUE-1)))			/* MSB set => negative number */+
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											{+
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												rawvalue |= 0xFFFE0000; 	/* set MSB for int32 */+
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											}+
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											externalChannel_mV[channel] = ADC_REF_VOLTAGE_MV * 2.0 / (float) pow(2,ADC_RESOLUTION_18BIT_VALUE);	/* calculate bit resolution */+
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							break;+
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			default: rawvalue = 0;+
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				break;+
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		}+
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		externalChannel_mV[channel] = externalChannel_mV[channel] * rawvalue / ADC_GAIN_8_VALUE;+
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		retValue = externalChannel_mV[channel];+
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	}+
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	return retValue;+
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}+
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float getExternalInterfaceChannel(uint8_t channel)+
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{+
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	float retval = 0;+
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+
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	if(channel < MAX_ADC_CHANNEL)+
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	{+
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		retval = externalChannel_mV[channel];+
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	}+
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	return retval;+
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}+
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