diff Small_CPU/Src/externalInterface.c @ 794:bb37d4f3e50e

Restructure UART based sensor handling: In the previous version every UART sensor instance had its own protocol handling instance (requests, timeout, errors). With the introduction of the multiplexer these functionalities had to be harmonized. E.g. only one errorhandling which is applied to all sensors. In the new structure the sensor communication is split into one function which takes care for the control needs of a sensor and one function which handles the incoming data. The functions behalf the same independend if the sensor are connected to multiplexer or directly to the OSTC. Second big change in the external sensor concepts is that the data processing is no longer focussed at the three existing ADC channels. Every external sensor (up to 3 ADC and 4 UART) sensor has its own instance. If the ADC slots are not in use then they may be used for visiualization of UART sensors by creating a mirror instance but this is no longer a must.
author Ideenmodellierer
date Mon, 31 Jul 2023 19:46:29 +0200
parents 19ab6f3ed52a
children e9eba334b942
line wrap: on
line diff
--- a/Small_CPU/Src/externalInterface.c	Thu Jul 27 21:52:19 2023 +0200
+++ b/Small_CPU/Src/externalInterface.c	Mon Jul 31 19:46:29 2023 +0200
@@ -25,12 +25,14 @@
 
 #include <math.h>
 #include <string.h>
+#include "data_central.h"
 #include "i2c.h"
 #include "externalInterface.h"
 #include "scheduler.h"
 #include "uart.h"
 #include "data_exchange.h"
 #include "pressure.h"
+#include "uartProtocol_O2.h"
 
 extern SGlobal global;
 extern UART_HandleTypeDef huart1;
@@ -54,6 +56,12 @@
 #define LOOKUP_CO2_CORR_TABLE_SCALE	(1000u)
 #define LOOKUP_CO2_CORR_TABLE_MAX	(30000u)
 
+#define REQUEST_INT_SENSOR_MS	(1500)		/* Minimum time interval for cyclic sensor data requests per sensor (UART mux) */
+#define COMMAND_TX_DELAY		(30u)		/* The time the sensor needs to recover from a invalid command request */
+#define TIMEOUT_SENSOR_ANSWER	(300)		/* Time till a request is repeated if no answer was received */
+
+#define activeSensorId (activeUartChannel + EXT_INTERFACE_MUX_OFFSET)	/* Used if UART channels are applied to Sensor map */
+
 static uint8_t activeChannel = 0;			/* channel which is in request */
 static uint8_t recBuf[ADC_ANSWER_LENGTH];
 static uint8_t timeoutCnt = 0;
@@ -65,17 +73,23 @@
 static uint8_t  externalUART_Protocol = 0;
 static uint16_t externalCO2Value;
 static uint16_t externalCO2SignalStrength;
-static uint16_t  externalCO2Status = 0;
+static uint16_t externalCO2Status = 0;
+static float 	externalCO2Scale = 0.0;
 
 static uint8_t lastSensorDataId = 0;
-static SSensorDataDiveO2 sensorDataDiveO2[MAX_ADC_CHANNEL];
+static SSensorDataDiveO2 sensorDataDiveO2[EXT_INTERFACE_SENSOR_CNT];
 static externalInterfaceAutoDetect_t externalAutoDetect = DETECTION_OFF;
 static externalInterfaceSensorType SensorMap[EXT_INTERFACE_SENSOR_CNT] ={ SENSOR_OPTIC, SENSOR_OPTIC, SENSOR_OPTIC, SENSOR_NONE, SENSOR_NONE};
 static externalInterfaceSensorType tmpSensorMap[EXT_INTERFACE_SENSOR_CNT];
 static externalInterfaceSensorType MasterSensorMap[EXT_INTERFACE_SENSOR_CNT];
+static externalInterfaceSensorType foundSensorMap[EXT_INTERFACE_SENSOR_CNT];
+static uint8_t	Mux2ADCMap[MAX_ADC_CHANNEL];
+static uint8_t externalInterface_SensorState[EXT_INTERFACE_SENSOR_CNT];
 
 static float LookupCO2PressureCorrection[LOOKUP_CO2_CORR_TABLE_MAX / LOOKUP_CO2_CORR_TABLE_SCALE];		/* lookup table for pressure compensation values */
 
+static uint16_t externalInterfaceMuxReqIntervall = 0;		/* delay between switching from one MUX channel to the next */
+static uint8_t activeUartChannel = 0;						/* Index of the sensor port which is selected by the mux or 0 if no mux is connected */
 
 void externalInterface_Init(void)
 {
@@ -91,6 +105,8 @@
 	}
 	global.deviceDataSendToMaster.hw_Info.checkADC = 1;
 
+	memset(Mux2ADCMap,0xFF, sizeof(Mux2ADCMap));
+
 /* Create a lookup table based on GSS application note AN001: PRESSURE COMPENSATION OF A CO2 SENSOR */
 /* The main purpose of the sensor in the dive application is to be a warning indicator */
 /* => no exact values necessary => a lookup table with 1000ppm scaling should be sufficient */
@@ -117,6 +133,7 @@
 	{
 		externalChannel_mV[index] = 0.0;
 	}
+	memset(externalInterface_SensorState,UART_O2_INIT,sizeof(externalInterface_SensorState));
 }
 
 
@@ -240,10 +257,24 @@
 uint8_t setExternalInterfaceChannel(uint8_t channel, float value)
 {
 	uint8_t retval = 0;
+	uint8_t localId = channel;
+	uint8_t index = 0;
 
-	if(channel < MAX_ADC_CHANNEL)
+	if(localId >= MAX_ADC_CHANNEL)		/* at the moment sensor visualization is focused on the three ADC channels => map Mux sensors */
 	{
-		externalChannel_mV[channel] = value;
+		for(index = 0; index < MAX_ADC_CHANNEL; index++)
+		{
+			if(Mux2ADCMap[index] == localId)
+			{
+				localId = index;
+				break;
+			}
+		}
+	}
+
+	if(localId < MAX_ADC_CHANNEL)
+	{
+		externalChannel_mV[localId] = value;
 		retval = 1;
 	}
 	return retval;
@@ -359,9 +390,45 @@
 	}
 }
 
+uint8_t externalInterface_GetActiveUartSensor()
+{
+	return activeUartChannel;
+}
+
+void externalInterface_SetSensorState(uint8_t sensorIdx, uint8_t state)
+{
+	if(sensorIdx < EXT_INTERFACE_SENSOR_CNT)
+	{
+		externalInterface_SensorState[sensorIdx] = state;
+	}
+}
+
+uint8_t externalInterface_GetSensorState(uint8_t sensorIdx)
+{
+	uint8_t ret = COMMON_SENSOR_STATE_INVALID;
+	if(sensorIdx < EXT_INTERFACE_SENSOR_CNT)
+	{
+		ret = externalInterface_SensorState[sensorIdx];
+	}
+	return ret;
+}
+
+/* The supported sensors from GSS have different scaling factors depending on their accuracy. The factor may be read out of the sensor */
+void externalInterface_SetCO2Scale(float CO2Scale)
+{
+	if((CO2Scale == 10) || (CO2Scale == 100))
+	{
+		externalCO2Scale = CO2Scale;
+	}
+}
+float externalInterface_GetCO2Scale()
+{
+	return externalCO2Scale;
+}
+
 void externalInterface_SetCO2Value(uint16_t CO2_ppm)
 {
-	float local_ppm = CO2_ppm * 10.0;		/* scalfactor */
+	float local_ppm = CO2_ppm * externalCO2Scale;
 
 #ifndef ENABLE_EXTERNAL_PRESSURE
 	float local_corr = 0.0;
@@ -379,7 +446,7 @@
 /* The external pressure value is passed via ADC channel2 and calibration is done at firmware => just forward sensor data */
 /* compensation is done at firmware side. This is for testing only. Take care the the same algorithm is taken as used for the lookup table */
 #endif
-	externalCO2Value = local_ppm / 10.0;
+	externalCO2Value = local_ppm / externalCO2Scale;
 }
 
 void externalInterface_SetCO2SignalStrength(uint16_t LED_qa)
@@ -411,13 +478,14 @@
 
 uint8_t externalInterface_GetSensorData(uint8_t sensorId, uint8_t* pDataStruct)
 {
+	uint8_t index = 0;
 	uint8_t localId = sensorId;
 	if(localId == 0xFF)
 	{
 		localId = lastSensorDataId;
 	}
 
-	if((pDataStruct != NULL) && (localId <= MAX_ADC_CHANNEL))
+	if((pDataStruct != NULL) && (localId <= EXT_INTERFACE_SENSOR_CNT))
 	{
 		memcpy(pDataStruct, &sensorDataDiveO2[localId], sizeof(SSensorDataDiveO2));
 	}
@@ -425,17 +493,39 @@
 	{
 		localId = 0xFF;
 	}
+	if(localId > MAX_ADC_CHANNEL)		/* at the moment sensor visualization is focused on the three ADC channels => map Mux sensors */
+	{
+		for(index = 0; index < MAX_ADC_CHANNEL; index++)
+		{
+			if(Mux2ADCMap[index] == localId)
+			{
+				localId = index;
+			}
+		}
+	}
+
 	return localId;
 }
 
 void externalInterface_SetSensorData(uint8_t sensorId, uint8_t* pDataStruct)
 {
+	uint8_t index = 0;
+
 	if(pDataStruct != NULL)
 	{
-		if((sensorId != 0xFF) && (sensorId < MAX_ADC_CHANNEL))
+		if((sensorId != 0xFF) && (sensorId < EXT_INTERFACE_SENSOR_CNT))
 		{
 			memcpy(&sensorDataDiveO2[sensorId], pDataStruct, sizeof(SSensorDataDiveO2));
 			lastSensorDataId = sensorId;
+			for(index = 0; index < MAX_MUX_CHANNEL; index++)
+			{
+				if(Mux2ADCMap[index] == sensorId)
+				{
+					memcpy(&sensorDataDiveO2[index], pDataStruct, sizeof(SSensorDataDiveO2));
+					lastSensorDataId = index;
+					break;
+				}
+			}
 		}
 		else
 		{
@@ -449,7 +539,7 @@
 {
 	if(pMap != NULL)
 	{
-		memcpy(MasterSensorMap, pMap, 5);		/* the map is not directly copied. Copy is done via cmd request */
+		memcpy(MasterSensorMap, pMap, EXT_INTERFACE_SENSOR_CNT);		/* the map is not directly copied. Copy is done via cmd request */
 	}
 
 }
@@ -470,16 +560,21 @@
 
 void externalInterface_AutodetectSensor()
 {
-	static uint8_t tmpMuxMapping[MAX_MUX_CHANNEL];
 	static uint8_t sensorIndex = 0;
 	static uint8_t uartMuxChannel = 0;
 	uint8_t index = 0;
+	uint8_t index2 = 0;
+	uint8_t cntSensor = 0;
+	uint8_t cntUARTSensor = 0;
+	uint8_t cmdString[10];
+	uint8_t cmdLength = 0;
 
 	if(externalAutoDetect != DETECTION_OFF)
 	{
 		switch(externalAutoDetect)
 		{
-			case DETECTION_INIT:	sensorIndex = 0;
+			case DETECTION_INIT:	externalInterfaceMuxReqIntervall = 1100;
+									sensorIndex = 0;
 									uartMuxChannel = 0;
 									tmpSensorMap[0] = SENSOR_OPTIC;
 									tmpSensorMap[1] = SENSOR_OPTIC;
@@ -487,12 +582,9 @@
 									tmpSensorMap[3] = SENSOR_NONE;
 									tmpSensorMap[4] = SENSOR_NONE;
 
-									for(index = 0; index < MAX_ADC_CHANNEL; index++)
-									{
-										UART_MapDigO2_Channel(index,index);		/* request all addresses */
-										tmpMuxMapping[index] = 0xff;
-									}
-									UART_MapDigO2_Channel(2,3);
+									memset(foundSensorMap, SENSOR_NONE, sizeof(foundSensorMap));
+									memset(externalInterface_SensorState,UART_O2_INIT,sizeof(externalInterface_SensorState));
+									memset(Mux2ADCMap,0, sizeof(Mux2ADCMap));
 
 									if(externalInterfacePresent)
 									{
@@ -523,6 +615,7 @@
 										if(externalChannel_mV[index] > MIN_ADC_VOLTAGE_MV)
 										{
 											tmpSensorMap[sensorIndex++] = SENSOR_ANALOG;
+											foundSensorMap[index] = SENSOR_ANALOG;
 										}
 										else
 										{
@@ -531,53 +624,50 @@
 									}
 									externalAutoDetect = DETECTION_UARTMUX;
 									externalInterface_SwitchUART(EXT_INTERFACE_UART_O2 >> 8);
-									UART_SetDigO2_Channel(MAX_MUX_CHANNEL);
+									UART_MUX_SelectAddress(MAX_MUX_CHANNEL);
+									uartO2_SetChannel(MAX_MUX_CHANNEL);
+									activeUartChannel = MAX_MUX_CHANNEL;
+									tmpSensorMap[EXT_INTERFACE_SENSOR_CNT-1] = SENSOR_MUX;
 				break;
-			case DETECTION_UARTMUX:  	if(UART_isDigO2Connected())
+			case DETECTION_UARTMUX:  	if(uartO2_isSensorConnected())
 										{
 											uartMuxChannel = 1;
+											tmpSensorMap[EXT_INTERFACE_SENSOR_CNT-1] = SENSOR_MUX;
+											foundSensorMap[EXT_INTERFACE_SENSOR_CNT-1] = SENSOR_MUX;
+										}
+										else
+										{
+											tmpSensorMap[EXT_INTERFACE_SENSOR_CNT-1] = SENSOR_NONE;
 										}
 										externalAutoDetect = DETECTION_DIGO2_0;
 										externalInterface_SwitchUART(EXT_INTERFACE_UART_O2 >> 8);
-										UART_SetDigO2_Channel(0);
-										
+										UART_MUX_SelectAddress(0);
+										uartO2_SetChannel(0);
+										activeUartChannel = 0;
+										tmpSensorMap[EXT_INTERFACE_MUX_OFFSET] = SENSOR_DIGO2;
+										externalInterface_SensorState[EXT_INTERFACE_MUX_OFFSET] = UART_O2_INIT;
+										externalInterface_SwitchUART(EXT_INTERFACE_UART_O2 >> 8);
 				break;
 			case DETECTION_DIGO2_0:
 			case DETECTION_DIGO2_1: 
 			case DETECTION_DIGO2_2:
 			case DETECTION_DIGO2_3:
-									if(UART_isDigO2Connected())
+									if(uartO2_isSensorConnected())
 									{
-										for(index = 0; index < 3; index++)	/* lookup a channel which may be used by digO2 */
-										{
-											if(tmpSensorMap[index] == SENSOR_NONE)
-											{
-												break;
-											}
-										}
-										if(index == 3)
-										{
-											tmpSensorMap[2] = SENSOR_DIGO2;  /* digital sensor overwrites ADC */
-										}
-										else
-										{
-											tmpSensorMap[index] = SENSOR_DIGO2;
-											tmpMuxMapping[externalAutoDetect - DETECTION_DIGO2_0] = index;
-											if(externalAutoDetect == DETECTION_DIGO2_2 )	/* special handling needed because channel is used twice during mux detection */
-											{
-												UART_MapDigO2_Channel(0xff, externalAutoDetect - DETECTION_DIGO2_0);
-											}
-										}
+										foundSensorMap[externalAutoDetect - DETECTION_DIGO2_0 + EXT_INTERFACE_MUX_OFFSET] = SENSOR_DIGO2;
 									}
-									else
-									{
-										UART_MapDigO2_Channel(0xff, externalAutoDetect - DETECTION_DIGO2_0);
-									}
+
 									if(uartMuxChannel)
 									{
 										externalInterface_SwitchUART(EXT_INTERFACE_UART_O2 >> 8);
-										UART_SetDigO2_Channel(uartMuxChannel);
-										if(uartMuxChannel < MAX_ADC_CHANNEL - 1)
+										UART_MUX_SelectAddress(uartMuxChannel);
+										externalInterface_SensorState[uartMuxChannel + EXT_INTERFACE_MUX_OFFSET] = UART_O2_INIT;
+										uartO2_SetChannel(uartMuxChannel);
+										activeUartChannel = uartMuxChannel;
+										tmpSensorMap[uartMuxChannel - 1 + EXT_INTERFACE_MUX_OFFSET] = SENSOR_NONE;
+										tmpSensorMap[uartMuxChannel + EXT_INTERFACE_MUX_OFFSET] = SENSOR_DIGO2;
+
+										if(uartMuxChannel < MAX_MUX_CHANNEL - 1)
 										{
 											uartMuxChannel++;
 										}
@@ -591,6 +681,14 @@
 									if(externalAutoDetect == DETECTION_CO2)
 									{
 										externalInterface_SwitchUART(EXT_INTERFACE_UART_CO2 >> 8);
+										if(tmpSensorMap[EXT_INTERFACE_SENSOR_CNT-1] == SENSOR_MUX)		/* switch sensor operation mode depending on HW config */
+										{
+											DigitalCO2_SendCmd(CO2CMD_MODE_POLL, cmdString, &cmdLength);
+										}
+										else
+										{
+											DigitalCO2_SendCmd(CO2CMD_MODE_STREAM, cmdString, &cmdLength);
+										}
 									}
 				break;
 			case DETECTION_CO2:		if(UART_isCO2Connected())
@@ -635,44 +733,53 @@
 									externalAutoDetect++;
 #endif
 				break;
-			case DETECTION_DONE:	if(uartMuxChannel)
+			case DETECTION_DONE:	externalAutoDetect = DETECTION_OFF;
+									externalInterface_SwitchUART(0);
+									activeUartChannel = 0xFF;
+									cntSensor = 0;
+									cntUARTSensor = 0;
+									for(index = 0; index < EXT_INTERFACE_SENSOR_CNT-1; index++)
 									{
-										tmpSensorMap[EXT_INTERFACE_SENSOR_CNT-1] = SENSOR_MUX;
-									}
-
-									for(index = 0; index < MAX_MUX_CHANNEL; index++)
-									{
-										UART_MapDigO2_Channel(tmpMuxMapping[index], index);
-									}
+										if((foundSensorMap[index] >= SENSOR_ANALOG) && (foundSensorMap[index] < SENSOR_TYPE_O2_END))
+										{
+											cntSensor++;
+										}
 
-									externalAutoDetect = DETECTION_OFF;
-									externalInterface_SwitchUART(0);
-
+										if((foundSensorMap[index] == SENSOR_DIGO2) || (foundSensorMap[index] == SENSOR_CO2))
+										{
+											cntUARTSensor++;
+										}
 
-									for(index = 0; index < MAX_ADC_CHANNEL; index++)
-									{
-										if(tmpSensorMap[index] == SENSOR_DIGO2) /* set Channel to first valid entry */
+										/* Map Mux O2 sensors to ADC Slot if ADC slot is not in use */
+										if(foundSensorMap[index] == SENSOR_DIGO2)
 										{
-											UART_SetDigO2_Channel(index);
-											break;
+											for(index2 = 0; index2 < MAX_ADC_CHANNEL; index2++)
+											{
+												if(foundSensorMap[index2] == SENSOR_NONE)
+												{
+													foundSensorMap[index2] = SENSOR_DIGO2M;		/* store a mirror instance needed for visualization */
+													Mux2ADCMap[index2] = index;
+													break;
+												}
+											}
 										}
 									}
-									for(index = 0; index < MAX_ADC_CHANNEL; index++)
+									externalInterfaceMuxReqIntervall = 0xFFFF;
+									if(cntSensor == 0)		/* return default sensor map if no sensor at all has been detected */
 									{
-										if(tmpSensorMap[index] != SENSOR_NONE)
+										foundSensorMap[0] = SENSOR_OPTIC;
+										foundSensorMap[1] = SENSOR_OPTIC;
+										foundSensorMap[2] = SENSOR_OPTIC;
+									}
+									else
+									{
+										if(cntUARTSensor != 0)
 										{
-											break;
+											externalInterfaceMuxReqIntervall = REQUEST_INT_SENSOR_MS / cntUARTSensor;
 										}
 									}
-
-									if(index == MAX_ADC_CHANNEL)		/* return default sensor map if no sensor at all has been detected */
-									{
-										tmpSensorMap[0] = SENSOR_OPTIC;
-										tmpSensorMap[1] = SENSOR_OPTIC;
-										tmpSensorMap[2] = SENSOR_OPTIC;
-									}
-									memcpy(SensorMap, tmpSensorMap, sizeof(tmpSensorMap));
-
+									memcpy(SensorMap, foundSensorMap, sizeof(foundSensorMap));
+									memset(externalInterface_SensorState,UART_O2_INIT,sizeof(externalInterface_SensorState));
 				break;
 			default:
 				break;
@@ -685,7 +792,10 @@
 {
 	char cmdString[10];
 	uint8_t cmdLength = 0;
-	uint8_t index;
+	uint8_t index, index2;
+	uint8_t cntUARTSensor = 0;
+	uint8_t lastMappedID = 0;
+
 
 	switch(Cmd & 0x00FF)		/* lower byte is reserved for commands */
 	{
@@ -699,14 +809,38 @@
 			break;
 		case EXT_INTERFACE_COPY_SENSORMAP:	if(externalAutoDetect == DETECTION_OFF)
 											{
-												memcpy(SensorMap, MasterSensorMap, 5);
-												for(index = 0; index < 3; index++)
+												memcpy(SensorMap, MasterSensorMap, sizeof(MasterSensorMap));
+												for(index = 0; index < EXT_INTERFACE_SENSOR_CNT; index++)
 												{
-													if(SensorMap[index] == SENSOR_DIGO2)
+													if((SensorMap[index] == SENSOR_DIGO2) || (SensorMap[index] == SENSOR_CO2))
+													{
+														cntUARTSensor++;
+													}
+													if(SensorMap[index] == SENSOR_DIGO2M)		/* find matching sensor for mirror */
 													{
-														break;
+														for(index2 = EXT_INTERFACE_MUX_OFFSET; index2 < EXT_INTERFACE_SENSOR_CNT; index2++)
+														{
+															if(SensorMap[index2] == SENSOR_DIGO2)
+															{
+																if(lastMappedID < index2)
+																{
+																	lastMappedID = index2;
+																	Mux2ADCMap[index] = index2;
+																	break;
+																}
+															}
+														}
 													}
 												}
+												if(cntUARTSensor > 0)
+												{
+													externalInterfaceMuxReqIntervall = REQUEST_INT_SENSOR_MS / cntUARTSensor;
+													activeUartChannel = 0xFF;
+												}
+												else
+												{
+													externalInterfaceMuxReqIntervall = 0xFFFF;
+												}
 											}
 			break;
 		default:
@@ -719,3 +853,146 @@
 	return;
 }
 
+uint8_t ExternalInterface_SelectUsedMuxChannel(uint8_t currentChannel)
+{
+	uint8_t index = currentChannel;
+	uint8_t newChannel = index;
+	uint8_t *pmap = externalInterface_GetSensorMapPointer(0);
+
+	do
+	{
+		index++;
+		if(index == MAX_MUX_CHANNEL)
+		{
+			index = 0;
+		}
+		if(((pmap[index + EXT_INTERFACE_MUX_OFFSET] == SENSOR_DIGO2) || (pmap[index + EXT_INTERFACE_MUX_OFFSET] == SENSOR_CO2))
+				&& (index != activeUartChannel))
+		{
+			newChannel = index;
+			break;
+		}
+	} while(index != currentChannel);
+
+	return newChannel;
+}
+
+void externalInterface_HandleUART()
+{
+	static uint8_t retryRequest = 0;
+	static uint32_t lastRequestTick = 0;
+	static uint32_t TriggerTick = 0;
+	uint8_t index = 0;
+	static uint8_t timeToTrigger = 0;
+	uint32_t tick =  HAL_GetTick();
+	uint8_t *pmap = externalInterface_GetSensorMapPointer(0);
+
+
+	UART_ReadData(pmap[activeSensorId]);
+
+	if(activeUartChannel == 0xFF)
+	{
+		activeUartChannel = ExternalInterface_SelectUsedMuxChannel(0);
+		uartO2_SetChannel(activeUartChannel);
+		if(pmap[EXT_INTERFACE_SENSOR_CNT-1] == SENSOR_MUX)
+		{
+			UART_MUX_SelectAddress(activeUartChannel);
+		}
+		UART_FlushRxBuffer();
+	}
+
+	if(externalInterfaceMuxReqIntervall != 0xFFFF)
+	{
+		if(externalInterface_SensorState[activeSensorId] == UART_O2_INIT)
+		{
+			lastRequestTick = tick;
+			TriggerTick = tick - 10;	/* just to make sure control is triggered */
+			timeToTrigger = 1;
+			retryRequest = 0;
+		}
+		else if(((retryRequest == 0)		/* timeout or error */
+				&& (((time_elapsed_ms(lastRequestTick,tick) > (TIMEOUT_SENSOR_ANSWER)) && (externalInterface_SensorState[activeSensorId] != UART_O2_IDLE))	/* retry if no answer after half request interval */
+					|| (externalInterface_SensorState[activeSensorId] == UART_O2_ERROR))))
+		{
+			/* The channel switch will cause the sensor to respond with an error message. */
+			/* The sensor needs ~30ms to recover before he is ready to receive the next command => transmission delay needed */
+
+			TriggerTick = tick;
+			timeToTrigger = COMMAND_TX_DELAY;
+			retryRequest = 1;
+		}
+
+		else if(time_elapsed_ms(lastRequestTick,tick) > externalInterfaceMuxReqIntervall)	/* switch sensor and / or trigger next request */
+		{
+			lastRequestTick = tick;
+			TriggerTick = tick;
+			retryRequest = 0;
+			timeToTrigger = 1;
+
+			if((externalInterface_SensorState[activeSensorId] == UART_O2_REQ_O2)		/* timeout */
+					|| (externalInterface_SensorState[activeSensorId] == UART_O2_REQ_RAW))
+			{
+				setExternalInterfaceChannel(activeSensorId,0.0);
+			}
+
+			if(pmap[EXT_INTERFACE_SENSOR_CNT-1] == SENSOR_MUX) /* select next sensor if mux is connected */
+			{
+				if(activeUartChannel < MAX_MUX_CHANNEL)
+				{
+					index = ExternalInterface_SelectUsedMuxChannel(activeUartChannel);
+					if(index != activeUartChannel)
+					{
+						timeToTrigger = 100;
+						activeUartChannel = index;
+						if(pmap[index + EXT_INTERFACE_MUX_OFFSET] == SENSOR_DIGO2)
+						{
+							uartO2_SetChannel(activeUartChannel);
+							UART_MUX_SelectAddress(activeUartChannel);
+						}
+					}
+				}
+			}
+			else
+			{
+				timeToTrigger = 1;
+			}
+		}
+		if((timeToTrigger != 0) && (time_elapsed_ms(TriggerTick,tick) > timeToTrigger))
+		{
+			timeToTrigger = 0;
+			switch (pmap[activeSensorId])
+			{
+				case SENSOR_MUX:
+				case SENSOR_DIGO2:	uartO2_Control();
+					break;
+			//	case SENSOR_CO2:	uartCO2_Control();
+					break;
+				default:
+					break;
+			}
+		}
+	}
+
+
+
+#if 0
+#ifdef ENABLE_CO2_SUPPORT
+		if(externalInterface_GetUARTProtocol() & (EXT_INTERFACE_UART_CO2 >> 8))
+		{
+			UART_HandleCO2Data();
+		}
+#endif
+#ifdef ENABLE_SENTINEL_MODE
+		if(externalInterface_GetUARTProtocol() & (EXT_INTERFACE_UART_SENTINEL >> 8))
+		{
+			UART_HandleSentinelData();
+		}
+#endif
+		if(externalInterface_GetUARTProtocol() & (EXT_INTERFACE_UART_O2 >> 8))
+		{
+			UART_HandleDigitalO2();
+		}
+#endif
+
+
+}