# 9. Software FAQ and HOWTOs¶

This sections shows different kind of actions related to the software.

## 9.1. How to start foxBMS if no messages are sent by CAN?¶

If no current sensor is connected to foxBMS, it will not start. This default behavior can be changed by setting the switch

#define CURRENT_SENSOR_PRESENT               TRUE


to FALSE as explaned in Important Switches in Code.

## 9.2. How to create a task and change its priority and period?¶

First, declare a new task configuration in the appltask_cfg.h file:

/**
*/


The task configuration is a struct of type BMS_Task_Definition_s and defined as follows:

/**
*/
typedef struct {
uint32_t Phase;          /*!< (ms)                                 */
uint32_t CycleTime;      /*!< (ms)                                 */
OS_PRIORITY_e Priority;  /*!<                                      */
uint32_t Stacksize;      /*!<  Defines the size, in words, of the
stack allocated to the idle task.   */

• Phase: phase offset of the task in ms
• CycleTime: cycle time of the task in ms
• Stacksize: stack size allocated to the task
• Priority: task priority for scheduling

The task priorities are defined by CMSIS and consist of seven priorities:

typedef enum  {
osPriorityIdle          = -3,          // /< priority: idle (lowest)
osPriorityLow           = -2,          // /< priority: low
osPriorityBelowNormal   = -1,          // /< priority: below normal
osPriorityNormal        =  0,          // /< priority: normal (default)
osPriorityAboveNormal   = +1,          // /< priority: above normal
osPriorityHigh          = +2,          // /< priority: high
osPriorityRealtime      = +3,          // /< priority: realtime (highest)
osPriorityError         =  0x84        // /< system cannot determine priority
//    or thread has illegal priority
} osPriority;


The priorities osPriorityRealtime, osPriorityHigh, osPriorityAboveNormal and osPriorityNormal are already used by the foxBMS engine and therefore should not be used. In conlusion the priorities osPriorityBelowNormal and osPriorityLow shall be used.

Second, add the task configuration in the appltask_cfg.c file:

/**
* predefined 10ms task for user code
*/
BMS_Task_Definition_s appl_tskdef_10ms = { 0,   10, osPriorityBelowNormal, 512/4 };


Third, declare a task handle and a task function in the appltask.c/h file:

 /**
*/

/**
* @brief   10ms engine application task
*/
extern void APPL_TSK_Cyclic_100ms(void);


The task initialization and creation is done in the function APPL_CreateTask() in the appltask.c file. Before assigning the task handle to the newly created task, a new thread needs to be defined for the operating system. This is done by a call of the function osThreadDef(name, thread, priority, instances, stacksz). The function parameters are:

• name: name of the function that represents the task
• priority: initial priority of the thread function
• instances: number of possible thread instances (0 -> only one instance)
• stacksize

The task handle is now, with a call of osThreadCreate, assigned to the task.

// Cyclic Task 10ms
appl_tskdef_10ms.Priority, 0, appl_tskdef_10ms.Stacksize);


The implementation of the task should be done like shown in the following example:

void APPL_TSK_Cyclic_10ms(void) {
while (os_boot != OS_SYSTEM_RUNNING)
{
;
}

osDelayUntil(os_schedulerstarttime, appl_tskdef_10ms.Phase);

while(1)
{
uint32_t currentTime = osKernelSysTick();

APPL_Cyclic_10ms();

osDelayUntil(currentTime, appl_tskdef_10ms.CycleTime);
}
}


Note

• Every task should have the while loop while(os_boot != OS_SYSTEM_RUNNING) at the beginning of the funtion. This prevents the task from being executed before foxBMS is completely initialized.
• osDelayUntil(os_schedulerstarttime, appl_tskdef_10ms.Phase) sets the wished phase offset of the task
• Tasks in FreeRTOS should never finish. Therefore, the actual task implementation is done in a while(1)-loop
• APPL_TSK_Cyclic_10ms serves as wrapper function for task implementation in APPL_Cyclic_10ms()
• The call of osDelayUntil(currentTime, appl_tskdef_10ms.CycleTime) sets the task in blocked state until the cycle time until the next period arrives
• Every task should be secured by the system monitoring module (DIAG_SysMonNotify())
• foxBMS provides two default tasks for user applications with a periods of 10ms and 100ms
void APPL_Cyclic_10ms(void) {
DIAG_SysMonNotify(DIAG_SYSMON_APPL_CYCLIC_10ms, 0);        // task is running, state = ok

/* User specific implementations:   */
/*   ...                            */
/*   ...                            */
}


## 9.3. How to add a software module and take it into account with WAF?¶

• Creation of a new subfolder (for example mymodule) in one of the existing source folders application, engine, general, module, module/utils)
• Copy of all source files to the newly created subfolder
• Modification of the wscript file located in the chosen existing source folder, to add the new module. For example, to add a software module in the application folder, in the includes section of the wscript, the following new line has to be added:
os.path.join(bld.srcnode.abspath(), 'src', 'application', 'mymodule'),


In case the new software module has to be used in another existing module, the same line has to be added in the wscript file corresponding to the existing module where it is imported.

## 9.4. How to change the multiplexer measurement sequence for the LTC driver?¶

The sequence is defined in module\config\ltc_cfg.c, via the array LTC_MUX_CH_CFG_t ltc_mux_seq_main_ch1[], which contains a concatenation of elements like:

{
.muxID    = 1,
.muxCh    = 0xFF,
},
{
.muxID    = 2,
.muxCh    = 0,
},
{
.muxID    = 2,
.muxCh    = 1,
},


There are 4 multiplexers with IDs from 0 to 3 on the foxBMS Slave Units. The multiplexer is chosen with the variable muxID. Each multiplexer has 8 channels, chosen with the variable muxCh (between 0 and 7). Channel 0xFF means that the multiplexer is disabled (i.e., high-impedance mode: none of the 8 inputs is connected to the output). With the code sequence shown above, multiplexer is first disabled, then channel 0 of multiplexer 2 is read, then channel 1 of multiplexer 2 is read.

Typically, multiplexer 0 and 1 are used for temperature measurement, and multiplexer 2 and 3 are used for balancing feedback (i.e., monitor if a cell is being balanced or not). As a consequence, by default, measurements of multiplexer 0 and 1 are stored in a database structure of type DATA_BLOCK_CELLTEMPERATURE_s and measurement of multiplexer 2 and 3 are stored in a database structure of type DATA_BLOCK_BALANCING_FEEDBACK_s.

For temperature measurements, the variable uint8_t ltc_muxsensortemperatur_cfg[6] contains the look-up table between temperature sensors and cells: the first entry defines the temperature sensor number assigned to the first cell, the second entry defines the temperature sensor number assigned to the second cell, and so on. If no look-up table is needed, this array should simply be filled with integers increasing from 0 to number of temperature sensors minus 1. In this example, muxsensortemperaturmain_cfg[6] has a size of 6 because it is the default number of temperature sensors supported by the foxBMS Slave Units. This must be adapted at two places:

• In module\config\ltc_cfg.c, where the variable is defined
• In module\config\ltc_cfg.h, in the declaration extern uint8_t ltc_muxsensortemperatur_cfg[6]

## 9.5. How to change the relation between voltages read by multiplexer via LTC6811-1 and temperatures?¶

The function float LTC_Convert_MuxVoltages_to_Temperatures(float v_adc) is defined in ltc_cfg.c. It gets a voltage in V as input and returns a temperature. It can simply be changed to meet the application needs.

To get the function converting the measured voltage to temperature, the following procedure can be followed if a Negative Temperature Coefficient resistor (NTC) is used :

1. Create a spreadsheet (e.g., in Microsoft Excel)
2. In the datasheet of the NTC, take the table giving the resistance versus the temperature
3. In the spreadsheet, define three columns:
• Temperature value (read from the NTC datasheet)
• Corresponding resistance value (read from the NTC datasheet)
• Voltage value provided by the voltage divider calculated with the NTC resistance for each temperature value. On the latest foxBMS Slave Unit, the voltage divider is formed by a 10kOhm resistor in series with the NTC, with a 3V power supply, as shown in Temperature Sensor Measurement
• Different slave versions may have different voltage dividers. Have a look a the Slaves documentation to select correct voltage divider for your slave.
4. Plot the temperature versus the corresponding measured voltage value (i.e., first column versus third column in the spreadsheet)
5. Fit a polynomial function to the plotted curve (e.g., by using Microsoft Excel)
6. Implement the polynom in float LTC_Convert_MuxVoltages_to_Temperatures(float Vout)

The function float LTC_Convert_MuxVoltages_to_Temperatures(float Vout) gets a voltage as input and outputs the corresponding temperature.

## 9.6. How to configure the MCU clock?¶

The configuration is defined in module/config/rcc_cfg.c via two structures:

RCC_OscInitTypeDef RCC_OscInitStruct = {
.OscillatorType = RCC_OSCILLATORTYPE_HSE,
.HSEState = RCC_HSE_ON,
.PLL.PLLState = RCC_PLL_ON,
.PLL.PLLSource = RCC_PLLSOURCE_HSE,
.PLL.PLLM = RCC_PLL_M,    // Oscillator Clock: 8MHz -> (8Mhz / 8) * 336 / 2 -> 168MHz
.PLL.PLLN = RCC_PLL_N,
.PLL.PLLP = RCC_PLL_P,
.PLL.PLLQ = RCC_PLL_Q     // Oscillator Clock: 8MHz -> (8Mhz / 8) * 336 / 7   -> 48MHz
};

RCC_ClkInitTypeDef RCC_ClkInitStruct = {
.ClockType = RCC_CLOCKTYPE_SYSCLK|RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2,
.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK,    // System Clock Source: PLL-Clock
// (Cortex-Core, AHB-Bus, DMA, memory)
.AHBCLKDivider = RCC_AHBCLKDivider,         // Div=1 , AHB  CLOCK: 168MHz
.APB1CLKDivider = RCC_APB1CLKDivider,       // Div=4 , APB1 CLOCK:  42MHz
.APB2CLKDivider = RCC_APB2CLKDivider        // Div=2 , APB2 CLOCK:  84MHz
};


Fig. 9.1 shows a summary of the system clocks, with the variables defined via the structures and their effect (either as divider or multiplier).

On the BMS-Master Board, a 8MHz oscillator is used as clock source. It should be noted that some of the multipliers/dividers can take all integers values in a certain range, while others can only take a specific set of values. The values must be defined so that the clock values are within the allowed ranges. These are defined in the microcontroller datasheet.

## 9.7. How to configure the LTC6811-1 and SPI clocks?¶

In module/config/ltc_cfg.h, the macro #define SPI_HANDLE_LTC &spi_devices[0] is defined. It points to a SPI handle: this SPI device will be used for the communication with the LTC6811-1. SPI handles are defined in module/config/spi_cfg.c. Depending on the SPI device chosen, the clock used will be peripheral clock 1 or 2 (this information is found in the STM32F4 datasheet). The clock used by the SPI device is obtained after division of the peripheral clock frequency. In the SPI handle, the value for the divider is defined via .Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_128. In the LTC6811-1 driver, the SPI frequency is read directly via a HAL function and all timings are adapted automatically. The user must only ensure that the SPI frequency used for the LTC6811-1 is not higher than 1MHz. This is the maximal frequency allowed for the LTC6811-1 communication (as defined in the LTC6811-1 datasheet).

## 9.8. How to configure the CAN clock?¶

If the APB1 (Peripheral) clock changes, the CAN timing has to be adapted according to the following formula:

\begin{align}\begin{aligned}\text{clock}_\text{CAN} = \frac{\text{APB1}}{(\text{prescaler} + \text{timequantums})}\\\text{timequantums} = 1 + \text{timequantumsBS1} + \text{timequantumsBS2}\end{aligned}\end{align}

The timequantums (TQ) are constrained to specific discrete values by the STM32 microcontroller.

Sample Configurations

 CAN clock APB1 Prescaler BS1 BS2 1.0 MHz 42 MHz 3 6 TQ 7 TQ 1.0 MHz 32 MHz 4 5 TQ 2 TQ 0.5 MHz 42 MHz 6 6 TQ 7 TQ 0.5 MHz 32 MHz 8 5 TQ 2 TQ

Example:

change the relevant low level driver handle in file /modules/config/can_cfg.c

CAN_HandleTypeDef hcan1 or CAN_HandleTypeDef hcan2

.Init.Prescaler = 3,        // CAN_CLOCK = APB1 = 42 MHz
// resulting CAN speed: APB1/prescaler/sumOfTimequants
// sum: 1tq for sync + BS1 + BS2
.Init.BS1 = CAN_BS1_6TQ,    // --> CAN = 42 MHz/(3*14) = 1.0 MHz
.Init.BS2 = CAN_BS2_7TQ,

\begin{align}\begin{aligned}\text{timequantums} = 1 + 6 + 7 = 14\\\text{clock}_{CAN} = \frac{42.0\text{\MHz}}{(3 \cdot 14)} = 1.0 \text{\MHz}\end{aligned}\end{align}

Further details can be found in STM32F4 datasheet.

## 9.9. How to configure and drive I/O ports?¶

The pin configuration of the hardware is is defined in const IO_PIN_CFG_s io_cfg[] in the file module/config/io_cfg.c with entries like:

{PIN_MCU_0_BMS_INTERFACE_SPI_MISO, IO_MODE_AF_PP, IO_PIN_NOPULL,
IO_SPEED_HIGH, IO_ALTERNATE_AF5_SPI1, IO_PIN_LOCK_ENABLE}


The parameters are:

• Pin: Defines the pin name (defined in module/config/io_mcu0_cfg.h).
• Mode: The possibilities of the mode are defined in module/config io_cfg.c via the enum type IO_PIN_MODES_e. Often used modes are IO_MODE_AF_PP for use of one alternate function of the pin, IO_MODE_INPUT to use the pin as an input, IO_MODE_OUTPUT_PP to use the pin as an output with push-pull functionality.
• Pinpull: Defines wether the pin is used without pull-up or pull-down (IO_PIN_NOPULL), to use the pin with pull-up (IO_PIN_PULLUP) or to use the pin with pull-down (IO_PIN_PULLDOWN).
• Speed: Defines the speed of the pin (IO_SPEED_LOW, IO_SPEED_MEDIUM, IO_SPEED_FAST or IO_SPEED_HIGH).
• Alternate: Defines if the signal/pin uses an alternate function or not. If no alternate function is used this is set to IO_ALTERNATE_NO_ALTERNATE. If the signal/pin uses a alternate function one can choose from the possibilities from the enumeration IO_PIN_ALTERNATE_e in module/config/io_cfg.h.
• Pinlock: IO_PIN_LOCK_DISABLE or IO_PIN_LOCK_ENABLE to disable or enable pin locking.
• Initvalue: Sets the initial state of the pin in case of an output pin; The pin is set to IO_PIN_RESET for 0/low and to IO_PIN_SET for 1/high. If no value is given for a output pin it is set to low.

As explained above, the signal names are to be defined in module/config/io_mcu0_cfg.h with macros like:

#define PIN_MCU_0_BMS_INTERFACE_SPI_MISO IO_PA_6


where IO_Px_y corresponds to the physical pin on the MCU, with x the port (e.g., A,B,C) and y the pin number on the port (e.g., 0,1,2).

This configuration is initialized in main.c with the function call IO_Init(&io_cfg[0]).

Pins configured as output are driven with the function with IO_PIN_RESET or IO_PIN_SET to set the pin to low or high. Example (The signal/pin name corresponds to the one defined in module/config/io_mcu0_cfg.h).:

IO_WritePin(PIN_MCU_0_BMS_INTERFACE_SPI_MISO, IO_PIN_RESET);     // set pin low
IO_WritePin(PIN_MCU_0_TO_MCU_1_INTERFACE_SPI_MISO, IO_PIN_SET);  // set pin high


The states of pins configured as input are read with the IO_ReadPin(<Signalname>) function. The function returns IO_PIN_RESET or IO_PIN_SET (0 or 1). Example with the signal/pin name corresponding to the one defined in module/config/io_mcu0_cfg.h:

IO_PIN_STATE_e pinstate = IO_PIN_RESET;


## 9.10. How to add and configure interrupts?¶

The interrupt configuration can be found in general/config/nvic_cfg.c via the variable NVIC_InitStruct_s nvic_interrupts[], which contains entries of the form: { DMA2_Stream2_IRQn, 2, NVIC_IRQ_LOCK_ENABLE, NVIC_IRQ_ENABLE }

The configuration parameters are:

• Symbolic name of interrupt source (as defined in the system file stm32f429xx.h)
• Interrupt priority: number between 0 and 15, a lower number means a higher priority
• Parameter irqlock: if set to NVIC_IRQ_LOCK_ENABLE, the interrupt is locked according to the initial state and cannot be modified by the interface functions NVIC_EnableInterrupts() or NVIC_DisableInterrupts()
• Initial state of interrupt source: set to NVIC_IRQ_ENABLE to get the interrupt enabled by the initialization function. In case of NVIC_IRQ_DISABLE, the interrupt must be activated by calling NVIC_EnableInterrupts() after the initialization

In general/config/stm32f4xx_it.c, a corresponding callback function must be defined (for example void DMA2_Stream2_IRQHandler(void) for DMA stream 2 of DMA device 2). It will be called when the interrupt is triggered.

For a proper operation, the interrupt handling (callback function) has to execute the following steps:

• Clear the pending interrupt with for example HAL_NVIC_ClearPendingIRQ(DMA2_Stream2_IRQn)
• Call the HAL IRQ handler (or a custom handler) with for example: HAL_DMA_IRQHandler(&dma_devices[0])

Note

Interrupt routines with interrupt priority above the maximum FreeRTOS configuration level (configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY) must not call FreeRTOS API functions. These interrupts are real-time interrupts, which are bypassing the operating system. Interrupt routines with interrupt priority equal or lower than this maximum level must call the corresponding FreeRTOS API functions with ending ...._FROM_ISR().

Check the documentation (datasheet, reference manual) of the interrupt source for additional steps.

## 9.11. How to add a database entry and to read/write it?¶

The example of the entry for cell voltages is taken. In engine\config\database_cfg.h, the definition of a block must be added #define DATA_BLOCK_ID_CELLVOLTAGE DATA_BLOCK_1 with one available block. The blocks are defined via the following enumeration:

typedef enum {
DATA_BLOCK00        = 0,
DATA_BLOCK01        = 1,
DATA_BLOCK02        = 2,
DATA_BLOCK03        = 3,
DATA_BLOCK04        = 4,
DATA_BLOCK05        = 5,
DATA_BLOCK06        = 6,
DATA_BLOCK07        = 7,
DATA_BLOCK08        = 8,
DATA_BLOCK09        = 9,
DATA_BLOCK10        = 10,
DATA_BLOCK_MAX      = DATA_MAX_BLOCK_NR,
} DATA_BLOCK_ID_TYPE_e;


If more than DATA_BLOCK_MAX blocks are needed, it must be changed in the defines:

#define DATA_MAX_BLOCK_NR                11


A structure must then be declared for the block ID created:

/*  data structure declaration of DATA_BLOCK_ID_CELLVOLTAGE */
typedef struct {
/* Timestamp info needs to be at the beginning. Automatically written on DB_WriteBlock      */
uint32_t timestamp;                       /*!< timestamp of database entry               */
uint32_t previous_timestamp;              /*!< timestamp of last database entry          */
/* data block entries                                                                    */
uint16_t      voltage[NR_OF_BAT_CELLS];   //unit: mV
uint8_t       state;
} DATA_BLOCK_CELLVOLTAGE_s;


This structure needs to contain a variable timestamp and previous_timestamp at the beginning of the struct. These timestamp are automatically updated each time new values are stored in the database. The reamaing struct consists of all the data needed for the entry. In mcu-primary\engine\config\database_cfg.c, a variable with the structure type must be declared

DATA_BLOCK_CELLVOLTAGE_s data_block_cellvoltage[DOUBLE_BUFFERING];


The user can choose SINGLE_BUFFERING or DOUBLE_BUFFERING. The last step is to add an entry in the structure DATA_BASE_HEADER_s data_base_header[]:

{
(void*)(&data_block_cellvoltage[0]),
sizeof(DATA_BLOCK_CELLVOLTAGE_s),
DOUBLE_BUFFERING,
},


With either SINGLE_BUFFERING or DOUBLE_BUFFERING (the same as in the structure declaration). When access to the created database entry is needed, a local variable with the corresponding type must be created in the module where it is needed: DATA_BLOCK_CELLVOLTAGE_s cellvoltage;

cellvoltage.voltage[i]


Getting the data from the database in the local variable is made via:

DB_ReadBlock(&cellvoltage ,DATA_BLOCK_ID_CELLVOLTAGE)


Storing data from the local variable to the database is made via:

DB_WriteBlock(&cellvoltage, DATA_BLOCK_ID_CELLVOLTAGE)


During each call of DB_WriteBlock() the timestamps will automatically be updated.

## 9.12. How to store data in the backup SRAM of the MCU?¶

The STM32F4 has 4kB Backup SRAM. Variables can be stored there with the keywork MEM_BKP_SRAM which is defined in src/general/config/global.h.

Example:

#define DIAG_FAIL_ENTRY_LENGTH (50)
DIAG_ERROR_ENTRY_s MEM_BKP_SRAM diag_memory[DIAG_FAIL_ENTRY_LENGTH];


## 9.13. How to manually add CAN entries (transmit and receive) and to change the transmit time period?¶

Several steps have to be done to add a transmit message and signal (message and signal in receive direction in parentheses):

File: module/config/cansignal_cfg.h

1. The message name must be added. For TX, i.e., transmit data, a message entry must be added in the enumeration CANS_messagesTx_e: (RX, i.e., receive, CANS_messagesRx_e)
2. Then one or more signal names must be added in the enumeration CANS_signalsTx_e (CANS_signalsRx_e)

File: module/config/can_cfg.c

1. The CAN message must be defined

3.1. In case a TX message should be defined - add the message for CAN0 or CAN1 in the respective array (const CAN_MSG_TX_TYPE_s can_CANx_messages_tx). The message looks like { 0x123, 8, 100, 20, NULL_PTR }

The parameters are:

• Message ID (11bit standard identifier used in foxBMS)
• Data Length Code (i.e., number of bytes), usually 8
• Transmit period in ms: must be multiple of CANS_TICK_MS
• Delay in ms for sending the message the first time: must be multiple of CANS_TICK_MS
• A function pointer to be called after transmission, NULL_PTR if nothing needs to be done

3.2 If a RX message needs to be configured, the message for CAN0 or CAN1 must be added in the respective array (CAN_MSG_RX_TYPE_s can0_RxMsgs[]). The message looks like { 0x123, 0xFFFF, 8, 0, CAN_FIFO0, NULL }

The parameters are:

• Message ID (11bit standard identifier used in foxBMS)
• Mask for the CAN hardware filter (Select mask or use 0x0000 to select list mode)
• Data Length Code (i.e., number of bytes), usually 8
• Hardware receive FIFO (CAN_FIFO0 or CAN_FIFO1)
• function pointer to be called after reception, usually NULL_PTR to do nothing because signals with respective function pointers are used

File: module/config/cansignal_cfg.c

1. Then the signals added in the header must be added in the .c file and in const CANS_signal_s cans_CANx_signals_tx[] (const CANS_signal_s cans_CANx_signals_rx[NR_SIGNALS_RX]).

A signal looks like:

{CANS_MSG_Name}, 0, 8, 0, 255, 1, 0, NULL_PTR, &cans_getsignaldata


The parameters are:

• Symbolic name of the message containing the signal (defined in CANS_messagesTx_e, in the header file)
• Start bit of signal
• Signal length in bits
• Minimum value (float)
• Maximum value (float)
• Scaling factor (float)
• Scaling offset (float)
• Callback function for setter (when CAN msg is received) (NULL_PTR if no function needed, e.g., for transmit)
• Callback function gor getter (when CAN msg is transmitted) (NULL_PTR if no function needed, e.g., for receive only)
1. The callback functions must be declared and implemented in cansignal_cfg.c.

## 9.14. How to adapt the CAN module when less than 12 battery cells/temperature sensors per module are used?¶

Five adaptions are necessary when removing unused battery cell voltages or temperatures This procedure is executed exemplarily for 9 cell voltages and 5 temperature sensors:

1. Adapt struct const CAN_MSG_TX_TYPE_s can_CAN0_messages_tx[] in file module/config/can_cfg.c:
{ 0x200, 8, 200, 20, NULL_PTR },  //!< Cell voltages module 0 cells 0 1 2
{ 0x201, 8, 200, 20, NULL_PTR },  //!< Cell voltages module 0 cells 3 4 5
{ 0x202, 8, 200, 20, NULL_PTR },  //!< Cell voltages module 0 cells 6 7 8
{ 0x203, 8, 200, 20, NULL_PTR },  //!< Cell voltages module 0 cells 9 10 11

{ 0x210, 8, 200, 30, NULL_PTR },  //!< Cell temperatures module 0 cells 0 1 2
{ 0x211, 8, 200, 30, NULL_PTR },  //!< Cell temperatures module 0 cells 3 4 5
{ 0x212, 8, 200, 30, NULL_PTR },  //!< Cell temperatures module 0 cells 6 7 8
{ 0x213, 8, 200, 30, NULL_PTR },  //!< Cell temperatures module 0 cells 9 10 11


Remove all unused CAN message depending on the number of used cells/sensors. In the example case remove cell voltage message 0x203 because we transmit only cell voltages 0-8. Additionally remove cell temperature message 0x212 and 0x213 because we only use temperatures 0-4. Repeat this process for all modules.

1. Adapt enum CANS_messagesTx_e in file module/config/cansignal_cfg.h:
CAN0_MSG_Mod0_Cellvolt_0,  //!< Module 0 Cell voltages 0-2
CAN0_MSG_Mod0_Cellvolt_1,  //!< Module 0 Cell voltages 3-5
CAN0_MSG_Mod0_Cellvolt_2,  //!< Module 0 Cell voltages 6-8
CAN0_MSG_Mod0_Cellvolt_3,  //!< Module 0 Cell voltages 9-11

CAN0_MSG_Mod0_Celltemp_0,  //!< Module 0 Cell temperatures 0-2
CAN0_MSG_Mod0_Celltemp_1,  //!< Module 0 Cell temperatures 3-5
CAN0_MSG_Mod0_Celltemp_2,  //!< Module 0 Cell temperatures 6-8
CAN0_MSG_Mod0_Celltemp_3,  //!< Module 0 Cell temperatures 9-11


Remove all unused enmus depending on the number of used cells/sensors. In the example case remove enum CAN0_MSG_Mod0_Cellvolt_3 because we transmit only cell voltages 0-8. Additionally remove cell temperature enum CAN0_MSG_Mod0_Celltemp_2 and CAN0_MSG_Mod0_Celltemp_3 because we only use temperatures 0-4. Repeat this process for all modules.

1. Adapt enum CANS_CAN0_signalsTx_e in file module/config/cansignal_cfg.h:
CAN0_SIG_Mod0_volt_valid_0_2,
CAN0_SIG_Mod0_volt_0,
CAN0_SIG_Mod0_volt_1,
CAN0_SIG_Mod0_volt_2,
CAN0_SIG_Mod0_volt_valid_3_5,
CAN0_SIG_Mod0_volt_3,
CAN0_SIG_Mod0_volt_4,
CAN0_SIG_Mod0_volt_5,
CAN0_SIG_Mod0_volt_valid_6_8,
CAN0_SIG_Mod0_volt_6,
CAN0_SIG_Mod0_volt_7,
CAN0_SIG_Mod0_volt_8,
CAN0_SIG_Mod0_volt_valid_9_11,
CAN0_SIG_Mod0_volt_9,
CAN0_SIG_Mod0_volt_10,
CAN0_SIG_Mod0_volt_11,

CAN0_SIG_Mod0_temp_valid_0_2,
CAN0_SIG_Mod0_temp_0,
CAN0_SIG_Mod0_temp_1,
CAN0_SIG_Mod0_temp_2,
CAN0_SIG_Mod0_temp_valid_3_5,
CAN0_SIG_Mod0_temp_3,
CAN0_SIG_Mod0_temp_4,
CAN0_SIG_Mod0_temp_5,
CAN0_SIG_Mod0_temp_valid_6_8,
CAN0_SIG_Mod0_temp_6,
CAN0_SIG_Mod0_temp_7,
CAN0_SIG_Mod0_temp_8,
CAN0_SIG_Mod0_temp_valid_9_11,
CAN0_SIG_Mod0_temp_9,
CAN0_SIG_Mod0_temp_10,
CAN0_SIG_Mod0_temp_11,


Remove all unused enmus depending on the number of used cells/sensors. In the example case remove enums CAN0_SIG_Mod0_volt_valid_9_11 to CAN0_SIG_Mod0_volt_11 because we transmit only cell voltages 0-8. Additionally remove cell temperature enums CAN0_SIG_Mod0_temp_5 to CAN0_SIG_Mod0_temp_11 because we only use temperatures 0-4. Repeat this process for all modules.

1. Adapt struct const CANS_signal_s cans_CAN0_signals_tx[] in file module/config/cansignal_cfg.c:
// Module 0 cell voltages
{ {CAN0_MSG_Mod0_Cellvolt_0}, 0, 8, 0, 0xFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_valid_0_2
{ {CAN0_MSG_Mod0_Cellvolt_0}, 8, 16, 0, 0xFFFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_0
{ {CAN0_MSG_Mod0_Cellvolt_0}, 24, 16, 0, 0xFFFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_1
{ {CAN0_MSG_Mod0_Cellvolt_0}, 40, 16, 0, 0xFFFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_2
{ {CAN0_MSG_Mod0_Cellvolt_1}, 0, 8, 0, 0xFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_valid_3_5
{ {CAN0_MSG_Mod0_Cellvolt_1}, 8, 16, 0, 0xFFFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_3
{ {CAN0_MSG_Mod0_Cellvolt_1}, 24, 16, 0, 0xFFFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_4
{ {CAN0_MSG_Mod0_Cellvolt_1}, 40, 16, 0, 0xFFFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_5
{ {CAN0_MSG_Mod0_Cellvolt_2}, 0, 8, 0, 0xFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_valid_6_8
{ {CAN0_MSG_Mod0_Cellvolt_2}, 8, 16, 0, 0xFFFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_6
{ {CAN0_MSG_Mod0_Cellvolt_2}, 24, 16, 0, 0xFFFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_7
{ {CAN0_MSG_Mod0_Cellvolt_2}, 40, 16, 0, 0xFFFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_8
{ {CAN0_MSG_Mod0_Cellvolt_3}, 0, 8, 0, 0xFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_valid_9_11
{ {CAN0_MSG_Mod0_Cellvolt_3}, 8, 16, 0, 0xFFFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_9
{ {CAN0_MSG_Mod0_Cellvolt_3}, 24, 16, 0, 0xFFFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_10
{ {CAN0_MSG_Mod0_Cellvolt_3}, 40, 16, 0, 0xFFFF, 1, 0, NULL_PTR, &cans_getvolt },  //!< CAN0_SIG_Mod0_volt_11

// Module 0 cell temperatures
{ {CAN0_MSG_Mod0_Celltemp_0}, 0, 8, 0, 0xFF, 1, 0, NULL_PTR, &cans_gettemp },  //!< CAN0_SIG_Mod0_volt_valid_0_2
{ {CAN0_MSG_Mod0_Celltemp_0}, 8, 16, -128, 527.35, 100, 128, NULL_PTR, &cans_gettemp },  //!< CAN0_SIG_Mod0_temp_0
{ {CAN0_MSG_Mod0_Celltemp_0}, 24, 16, -128, 527.35, 100, 128, NULL_PTR, &cans_gettemp },  //!< CAN0_SIG_Mod0_temp_1
{ {CAN0_MSG_Mod0_Celltemp_0}, 40, 16, -128, 527.35, 100, 128, NULL_PTR, &cans_gettemp },  //!< CAN0_SIG_Mod0_temp_2
{ {CAN0_MSG_Mod0_Celltemp_1}, 0, 8, 0, 0xFF, 1, 0, NULL_PTR, &cans_gettemp },  //!< CAN0_SIG_Mod0_volt_valid_3_5
{ {CAN0_MSG_Mod0_Celltemp_1}, 8, 16, -128, 527.35, 100, 128, NULL_PTR, &cans_gettemp },  //!< CAN0_SIG_Mod0_temp_3
{ {CAN0_MSG_Mod0_Celltemp_1}, 24, 16, -128, 527.35, 100, 128, NULL_PTR, &cans_gettemp },  //!< CAN0_SIG_Mod0_temp_4
{ {CAN0_MSG_Mod0_Celltemp_1}, 40, 16, -128, 527.35, 100, 128, NULL_PTR, &cans_gettemp },  //!< CAN0_SIG_Mod0_temp_5
{ {CAN0_MSG_Mod0_Celltemp_2}, 0, 8, 0, 0xFF, 1, 0, &cans_gettemp },  //!< CAN0_SIG_Mod0_volt_valid_6_8
{ {CAN0_MSG_Mod0_Celltemp_2}, 8, 16, -128, 527.35, 100, 128, NULL_PTR, &cans_gettemp },  //!< CAN0_SIG_Mod0_temp_6
{ {CAN0_MSG_Mod0_Celltemp_2}, 24, 16, -128, 527.35, 100, 128, NULL_PTR, &cans_gettemp },  //!< CAN0_SIG_Mod0_temp_7
{ {CAN0_MSG_Mod0_Celltemp_2}, 40, 16, -128, 527.35, 100, 128, NULL_PTR, &cans_gettemp },  //!< CAN0_SIG_Mod0_temp_8
{ {CAN0_MSG_Mod0_Celltemp_3}, 0, 8, 0, 0xFF, 1, 0, NULL_PTR, &cans_gettemp },  //!< CAN0_SIG_Mod0_volt_valid_9_11
{ {CAN0_MSG_Mod0_Celltemp_3}, 8, 16, -128, 527.35, 100, 128, NULL_PTR, &cans_gettemp },  //!< CAN0_SIG_Mod0_temp_9
{ {CAN0_MSG_Mod0_Celltemp_3}, 24, 16, -128, 527.35, 100, 128, NULL_PTR, &cans_gettemp },  //!< CAN0_SIG_Mod0_temp_10
{ {CAN0_MSG_Mod0_Celltemp_3}, 40, 16, -128, 527.35, 100, 128, NULL_PTR, &cans_gettemp },  //!< CAN0_SIG_Mod0_temp_11


Remove all unused struct entries depending on the number of used cells/sensors. Repeat this process for all modules.

1. Adapt functions cans_getvolt and cans_gettemp in file module/config/cansignal_cfg.c:

Remove all case-statements for which the signals have been deleted in the previous steps.

## 9.15. How to adapt the CAN module when less or more than 8 battery modules are used?¶

When less than 8 modules are used, the same procedure as described in How to adapt the CAN module when less or more than 8 battery modules are used? must be used but only the unused modules instead of unused cell voltages/temperatures must be deleted. If additional modules should be added also follow these instructions but instead of deleting these signals and CAN messages add the wished number of new messages.

Morover an adaption of the functions cans_getvolt and cans_gettemp in file module/config/cansignal_cfg.c is necessary:

// Determine module and cell number
if (sigIdx - CAN0_SIG_Mod0_volt_valid_0_2 < CANS_MODULSIGNALS_VOLT) {
modIdx = 0;
cellIdx = sigIdx - CAN0_SIG_Mod0_volt_valid_0_2;
} else if (sigIdx - CAN0_SIG_Mod1_volt_valid_0_2 < CANS_MODULSIGNALS_VOLT) {
modIdx = 1;
cellIdx = sigIdx - CAN0_SIG_Mod1_volt_valid_0_2;
} else if (sigIdx - CAN0_SIG_Mod2_volt_valid_0_2 < CANS_MODULSIGNALS_VOLT) {
modIdx = 2;
cellIdx = sigIdx - CAN0_SIG_Mod2_volt_valid_0_2;
} else if (sigIdx - CAN0_SIG_Mod3_volt_valid_0_2 < CANS_MODULSIGNALS_VOLT) {
modIdx = 3;
cellIdx = sigIdx - CAN0_SIG_Mod3_volt_valid_0_2;
} else if (sigIdx - CAN0_SIG_Mod4_volt_valid_0_2 < CANS_MODULSIGNALS_VOLT) {
modIdx = 4;
cellIdx = sigIdx - CAN0_SIG_Mod4_volt_valid_0_2;
} else if (sigIdx - CAN0_SIG_Mod5_volt_valid_0_2 < CANS_MODULSIGNALS_VOLT) {
modIdx = 5;
cellIdx = sigIdx - CAN0_SIG_Mod5_volt_valid_0_2;
} else if (sigIdx - CAN0_SIG_Mod6_volt_valid_0_2 < CANS_MODULSIGNALS_VOLT) {
modIdx = 6;
cellIdx = sigIdx - CAN0_SIG_Mod6_volt_valid_0_2;
} else if (sigIdx - CAN0_SIG_Mod7_volt_valid_0_2 < CANS_MODULSIGNALS_VOLT) {
modIdx = 7;
cellIdx = sigIdx - CAN0_SIG_Mod7_volt_valid_0_2;
}


This if statement performs a module detection to allocate the correct cell voltage to the respective CAN message. This statement needs to be shortened/extended depending on the number of used modules. The same method is used to allocate the cell temperatures and thus needs to be adapted as well.

Note

The define CANS_MODULSIGNALS_TEMP is calculated as followed:

#define CANS_MODULSIGNALS_TEMP  (CAN0_SIG_Mod1_volt_valid_0_2 - CAN0_SIG_Mod0_temp_valid_0_2)


When only one module is used this define needs to be redefined on the next signal used after the last temperature signal of module 0. If no signal is defined after the module 0 temperature signals use the last defined temperature signal. For the default configuration of foxBMS this could look like this:

#define CANS_MODULSIGNALS_TEMP  ((CAN0_SIG_Mod0_temp_11 - CAN0_SIG_Mod0_temp_valid_0_2) + 1)


## 9.17. How to add an entry for the diag module?¶

Adding a new sensitivity level is done in src/engine/config/diag_cfg.h by adding a new #define in:

#define DIAG_ERROR_SENSITIVITY_HIGH        (0)   // logging at first event
#define DIAG_ERROR_SENSITIVITY_MID         (5)   // logging at fifth event
#define DIAG_ERROR_SENSITIVITY_LOW         (10)  // logging at tenth event
#define DIAG_ERROR_SENSITIVITY_CUSTOM      (100) // logging at 100th event


and errors can be defined:

#define     DIAG_CH_CUSTOM_FAILURE             DIAG_ID_XX


and the error is then added in DIAG_CH_CFG_s  diag_ch_cfg[] in file src/engine/config/diag_cfg.c:

DIAG_CH_CFG_s  diag_ch_cfg[] = {
{DIAG_CH_CUSTOM_FAILURE,        DIAG_GENERAL_TYPE, DIAG_ERROR_SENSITIVITY_HIGH,
DIAG_RECORDING_ENABLED, DIAG_ENABLED, dummyfu},


The number of logged error events can be changed by modifying the value of the macro:

#define DIAG_FAIL_ENTRY_LENGTH               (50)    // Number of errors that can be logged


Note

The diag module is a powerfull module for general error handling. The user has to be aware of timings when using custom diag entries. As example how to use this module correct syscontrol is choosen. - The function SYSCTRL_Trigger() is called in the 10ms task (ENG_TSK_Cyclic_10ms()), meaning every 10ms this function must be executed. - In the diagnosis-module header diag_cfg.h there is the enum DIAG_SYSMON_MODULE_ID_e for the different error types that are handeled by the diagnosismodule. For syscontrol errors there is DIAG_SYSMON_SYSCTRL_ID. - In the diagnosis-module source diag_cfg.c there is the diag_sysmon_ch_cfg[] array assigning timings to this error, in this case 20ms.

{DIAG_SYSMON_SYSCTRL_ID, DIAG_SYSMON_CYCLICTASK, 20,
DIAG_RECORDING_ENABLED, DIAG_ENABLED, dummyfu2},


This means every time SYSCTRL_Trigger() is called, the function indicating syscontrol is running has to be exectued. If this is not done, the diagnosis module will set the syscontrol to the error state. Therefore, the user must set up functions, which are wanted to be supervised by the diagnosis module, and that they are still running, in this way:

void SYSCTRL_Trigger(SYSCTRL_TRIG_EVENT_e event) {
DIAG_SysMonNotify(DIAG_SYSMON_SYSCTRL_ID, 0);    // task is running, therefore
// reset state to 0
/* user code */
}


## 9.18. How to configure contactors without feedback?¶

In the file src/module/config/contactor_cfg.c, the contactors are defined with:

CONT_CFG_s cont_contactors_cfg[NR_OF_CONTACTORS] = {
{CONT_MAIN_PLUS_CONTROL,        CONT_MAIN_PLUS_FEEDBACK,        CONT_FEEDBACK_NORMALLY_OPEN},
{CONT_PRECHARGE_PLUS_CONTROL,   CONT_PRECHARGE_PLUS_FEEDBACK,   CONT_FEEDBACK_NORMALLY_OPEN},
{CONT_MAIN_MINUS_CONTROL,       CONT_MAIN_MINUS_FEEDBACK,       CONT_FEEDBACK_NORMALLY_OPEN}
};


The following change must be made to configure a contactor without feedback. In this case, the precharge contactor is taken as example:

{CONT_PRECHARGE_PLUS_CONTROL,   CONT_PRECHARGE_PLUS_FEEDBACK,   CONT_HAS_NO_FEEDBACK}


With this configuration, the feedback pin (CONT_PRECHARGE_PLUS_FEEDBACK) is ignored and the feedback value will always be equal to the expected value for the precharge contactor. This configuration should not be used without precautions since the safety level will be reduced.

## 9.19. How to simply trigger events via CAN?¶

The CAN message with ID 0x100 is considered as a debug message. If received, the function cans_setdebug() defined in cansignal_cfc.c is called. There, a switch case is used on the first byte (byte0) of the message to define what to do. This means that 256 actions are possible, and that 7 bytes remain to transfer data in the debug message.

## 9.20. How to start/stop balancing the battery cells?¶

When the #define BALANCING_DEFAULT_INACTIVE is set to FALSE, foxBMS starts the balancing process automatically if the balancing requirements are met. The balancing behavior is described in details in the documentation of the Balancing module.

This behavior can be influenced via a debug message sent per CAN (How to simply trigger events via CAN?).

When the data 0E 01 00 00 00 00 00 00 is sent, the balancing state machine goes to the BAL_STATEMACH_INACTIVE_OVERRIDE state. No balancing takes place.

When the data 0E 03 00 00 00 00 00 00 is sent, the balancing state machine goes to the BAL_STATEMACH_ACTIVE_OVERRIDE state. Balancing takes place without taking into account the state of the bms module, the current flowing through the battery and the minimum cell voltage in the battery pack.

When the data 0E 02 00 00 00 00 00 00 is sent, the balancing state machine goes out of the override state. Balancing takes place taking into account the state of the bms module, the current flowing through the battery and the minimum cell voltage in the battery pack.

## 9.21. How to set the initial SOC value via CAN?¶

This is done via the debug message with the first byte (byte0) equal to 11 (0x0B). The SOC is defined via the next two bytes (i.e., on 16bit: byte1 byte2). The SOC is given in 0.01% unit, which means that the 16bit number should be comprised between 0 and 10000. If a smaller value is given, the SOC will be set to 0%. If a greater value is given, SOC will be set to 100%.

## 9.22. How to configure the voltage inputs?¶

This number is changed in batterysystem_cfg.h with the define BS_NR_OF_BAT_CELLS_PER_MODULE. In addition, the variable

const uint8_t ltc_voltage_input_used[BS_MAX_SUPPORTED_CELLS]


must be adapted, too, in ltc_cfg.c.

It has the size of BS_MAX_SUPPORTED_CELLS. If a cell voltage is connected to the LTC IC input, 1 must be written in the table. Otherwise, 0 must be written.

For instance, if 5 cells are connected to inputs 0, 2, 5, 7, 11,

#define BS_NR_OF_BAT_CELLS_PER_MODULE               5


must be used and

const uint8_t ltc_voltage_input_used[BS_MAX_SUPPORTED_CELLS] = {
1 ,
0 ,
1 ,
0 ,
0 ,
1 ,
0 ,
1 ,
0 ,
0 ,
0 ,
1 ,
};


must be defined. The number of 1 in the table must be equal to BS_NR_OF_BAT_CELLS_PER_MODULE.

## 9.23. How to add/remove temperature sensors?¶

To add one temperature sensor, the first step is to change:

#define BS_NR_OF_TEMP_SENSORS_PER_MODULE           6


to:

#define BS_NR_OF_TEMP_SENSORS_PER_MODULE           7


in batterysystem_cfg.h.

However, this obvious step is not sufficient.

In ltc_cfg.c, the variable LTC_MUX_CH_CFG_s ltc_mux_seq_main_ch1[] which indicates the channel sequence to read on the multiplexer has to be modified. One sensor channel on one multiplexer has to be added. In this example, on the multiplexer with the ID 0 and channel 6 is read additionally.

Concretely:

{
.muxID    = 1,
.muxCh    = 0xFF,
},
{
.muxID    = 2,
.muxCh    = 0xFF,
},
{
.muxID    = 3,
.muxCh    = 0xFF,
},
{
.muxID    = 0,
.muxCh    = 0,
},
{
.muxID    = 0,
.muxCh    = 1,
},
{
.muxID    = 0,
.muxCh    = 2,
},
{
.muxID    = 0,
.muxCh    = 3,
},
{
.muxID    = 0,
.muxCh    = 4,
},
{
.muxID    = 0,
.muxCh    = 5,
},
{
.muxID    = 0,      //configure the multiplexer to be used
.muxCh    = 6,      //configure input to ne used on the selected multiplexer
},


{
.muxID    = 1,
.muxCh    = 0xFF,
},
{
.muxID    = 2,
.muxCh    = 0xFF,
},
{
.muxID    = 3,
.muxCh    = 0xFF,
},
{
.muxID    = 0,
.muxCh    = 0,
},
{
.muxID    = 0,
.muxCh    = 1,
},
{
.muxID    = 0,
.muxCh    = 2,
},
{
.muxID    = 0,
.muxCh    = 3,
},
{
.muxID    = 0,
.muxCh    = 4,
},
{
.muxID    = 0,
.muxCh    = 5,
},


Then the look-up table must be modified: it allows defining the correspondence between multiplexer channel and sensor order in the temperature array. By default, the mapping keeps the same order. In the previous example:

const uint8_t ltc_muxsensortemperatur_cfg[6] = {
1-1 ,       /*!< index 0 = mux 0, ch 0 */
2-1 ,       /*!< index 1 = mux 0, ch 1 */
3-1 ,       /*!< index 2 = mux 0, ch 2 */
4-1 ,       /*!< index 3 = mux 0, ch 3 */
5-1 ,       /*!< index 4 = mux 0, ch 4 */
6-1 ,       /*!< index 5 = mux 0, ch 5 */
//7-1 ,     /*!< index 6 = mux 0, ch 6 */
//8-1 ,     /*!< index 7 = mux 0, ch 7 */
//9-1 ,     /*!< index 8 = mux 1, ch 0 */
//10-1 ,    /*!< index 9 = mux 1, ch 1 */
//11-1 ,    /*!< index 10 = mux 1, ch 2 */
//12-1 ,    /*!< index 11 = mux 1, ch 3 */
//13-1 ,    /*!< index 12 = mux 1, ch 4 */
//14-1 ,    /*!< index 13 = mux 1, ch 5 */
//15-1 ,    /*!< index 14 = mux 1, ch 6 */
//16-1      /*!< index 15 = mux 1, ch 7 */
};


must be changed to:

const uint8_t ltc_muxsensortemperatur_cfg[7] = {
1-1 ,       /*!< index 0 = mux 0, ch 0 */
2-1 ,       /*!< index 1 = mux 0, ch 1 */
3-1 ,       /*!< index 2 = mux 0, ch 2 */
4-1 ,       /*!< index 3 = mux 0, ch 3 */
5-1 ,       /*!< index 4 = mux 0, ch 4 */
6-1 ,       /*!< index 5 = mux 0, ch 5 */
7-1 ,     /*!< index 6 = mux 0, ch 6 */
//8-1 ,     /*!< index 7 = mux 0, ch 7 */
//9-1 ,     /*!< index 8 = mux 1, ch 0 */
//10-1 ,    /*!< index 9 = mux 1, ch 1 */
//11-1 ,    /*!< index 10 = mux 1, ch 2 */
//12-1 ,    /*!< index 11 = mux 1, ch 3 */
//13-1 ,    /*!< index 12 = mux 1, ch 4 */
//14-1 ,    /*!< index 13 = mux 1, ch 5 */
//15-1 ,    /*!< index 14 = mux 1, ch 6 */
//16-1      /*!< index 15 = mux 1, ch 7 */
};


A last step has to be done in ltc_cfg.h: adjust the size of the array, by changing:

extern const uint8_t ltc_muxsensortemperatur_cfg[6];


into:

extern const uint8_t ltc_muxsensortemperatur_cfg[7];


The same procedure must be used to remove a temperature sensor.

## 9.24. How to change the resolution of the temperature values stored?¶

The scaling of the raw values read from the LTC6811-1 is made in ltc.c, in the function static void LTC_SaveTemperatures_SaveBalancingFeedback(void). First, the raw data are read from the SPI buffer with:

val_ui=*((uint16_t *)(&LTC_MultiplexerVoltages[2*((LTC_NUMBER_OF_LTC_PER_MODULE*i*LTC_N_MUX_CHANNELS_PER_LTC)+muxseqptr->muxID*LTC_N_MUX_CHANNELS_PER_MUX+muxseqptr->muxCh)]));


Then the raw data are scaled and are available in Volt:

val_fl = ((float)(val_ui))*100e-6;


Then the read voltage is converted into a temperature with a look-up table:

val_si = (int16_t)(LTC_Convert_MuxVoltages_to_Temperatures(val_fl));


The last step is to store the temperature into a sint16 variable:

ltc_celltemperature.temperature[i*(NR_OF_TEMP_SENSORS_PER_MODULE)+sensor_idx]=val_si;


At this step, the resolution can be changed. For instance, m°C could be stored instead of °C.

## 9.25. How to enable and disable the checksum?¶

The checksum mechanism is enabled via the following define in the file general.h:

#define BUILD_MODULE_ENABLE_FLASHCHECKSUM 1


## 9.26. How to call a user function to implement a specific algorithm?¶

In embedded-software\mcu-primary\src\application\config\appltask_cfg.c, the user function must simply be called in one of the periodic user function:

void APPL_Cyclic_1ms(void)
void APPL_Cyclic_10ms(void)
void APPL_Cyclic_100ms(void)


depending on the periodicity needed. The user function can access system data via the database.

For instance, to access the voltages, a structure must be declared with

DATA_BLOCK_CELLVOLTAGE_s voltages;


DB_ReadBlock(&voltages, DATA_BLOCK_ID_CELLVOLTAGE);

The field voltages.timestamp is updated with the system timestamp (in ms) everytime new voltages are written in the database. This timestamp can be used to check if the voltages have been updated.