LTC6811.c File Reference

LTC6811 Drivers. More...

#include "LTC6811.h"

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Macros
#define	BOARD_IS_FUCKED   0
#define	PEC_TABLE_SIZE   256
#define	UNDER_TEMP_LIMIT   10
#define	OVER_TEMP_LIMIT   55

Functions
void	initPECTable (void)
	Initializes Packet Error Code LUT by generating PEC look up table -> call on startup.
uint16_t	calculatePEC (uint8_t len, uint8_t *data)
	This method is used when sending a command to calculate the necessary PEC bytes to follow command bytes. Should be used when receiving data to compare receieved PEC with expected PEC value.
void	writeConfigAddress (BMSConfigStructTypedef *cfg, uint8_t address)
	this method is used for cellDischarge in order to write configuration datra to the LTC with specified address
void	writeConfigAll (BMSConfigStructTypedef *cfg)
	This function is called every loop to accommodate dischargeCells method Specifically writes configuration data (UV, OV, ADCMode, etc) to BMSConfig struct.
bool	readCellVoltage (uint8_t address, uint16_t cellVoltage[12])
	This function sends an ADCV command that begins conversion for every cell to specified LTC. This results in the function readings all cell voltage registers using the readRegister function.
bool	readAllCellVoltages (CellData bmsData[144])
	This function reads all cell voltages by essentially parsing each board and reading the individual cell voltages. These are then stored in the bmsData array, along with the cell number that is associated with the reading.
bool	readCellTemp (uint8_t address, uint16_t cellTemp[4], bool dcFault[4], bool tempFault[4])
	This function initiates ADC conversion for GPIO inputs connected to temperature sensors. Reads auxiliary register groups using readRegister function. Then, converts measured voltage into temperature based on temperature sensor response. Also checks for disconnected temperature sensor and OT faults. NOTE: We only read 4 temps per board, and they are the 4 highest temps on each board.
bool	readAllCellTemps (CellData bmsData[144])
	This function reads cell temps from all of our board by calling readCellTemp for each board. NOTE : This is not proven to work properly yet.
bool	readConfig (uint8_t address, uint8_t cfg[8])
	This method uses general readRegister function to check current state of LTC configuration reg. Mostly used for testing purposes.
bool	checkAllCellConnections (BMSConfigStructTypedef cfg, CellData bmsData[144])
	This function checks the cell connections of each cell in the BMS data array. Currently not used, as we have not been able to get it working, but the whole idea is that this function compares previously measured values to open wire check values, and if there is a significant drop in voltage, cell is allegedly disconnected.
bool	dischargeCellGroups (BMSConfigStructTypedef *cfg, bool cellDischarge[12][12])
	This function writes the configuration struct of cells that are currently being discharged. This is to track which cells are // being discharged while running our balancing algorithm.
void	wakeup_idle ()
	This function is used to wakeup the LTC chip that we want to use to get readings from.
bool	poll_single_secondary_voltage_reading (uint8_t board_num, BMSConfigStructTypedef *cfg, CellData bmsData[144])
bool	poll_single_secondary_temp_reading (uint8_t board_num, BMSConfigStructTypedef *cfg, CellData bmsData[144])
bool	readRegister (CommandCodeTypedef command, uint8_t address, uint16_t *data)
	Reads register specified by command from specified board address.
void	sendBroadcastCommand (CommandCodeTypedef command)
	Sends specified write only command to every LTC in the chain (ex: ADCV)
void	sendAddressCommand (CommandCodeTypedef command, uint8_t address)
	Sends specified write-only command to LTC with the specified address.

Variables
uint16_t	pec15Table [PEC_TABLE_SIZE]
uint16_t	CRC15_POLY = 0x4599

Detailed Description

LTC6811 Drivers.

Matt Vlasaty: March 29th, 2019 Aditya Nikumbh: Refactored Jan 31, 2024 David Lacayo: April, 2024

Todo

• checkCellConnection return value needs to disregard unused cell inputs
• resolve issue with writeConfig not changing every bit in the first register group
• test functions used to read from every board (readAllCellVoltages should be [12][8])
• minor changes (using more user-defined constants, changing return values)

Macro Definition Documentation

BOARD_IS_FUCKED

#define BOARD_IS_FUCKED   0

OVER_TEMP_LIMIT

#define OVER_TEMP_LIMIT   55

PEC_TABLE_SIZE

#define PEC_TABLE_SIZE   256

UNDER_TEMP_LIMIT

#define UNDER_TEMP_LIMIT   10

Function Documentation

calculatePEC()

uint16_t calculatePEC	(	uint8_t	len,
		uint8_t *	data )

This method is used when sending a command to calculate the necessary PEC bytes to follow command bytes. Should be used when receiving data to compare receieved PEC with expected PEC value.

Parameters

len	is the number of bytes that we will be stepping through in our data
data	is the data that we will be using to calculate the expected PEC

Returns

the expected PEC value

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checkAllCellConnections()

bool checkAllCellConnections	(	BMSConfigStructTypedef	cfg,
		CellData	bmsData[144] )

This function checks the cell connections of each cell in the BMS data array. Currently not used, as we have not been able to get it working, but the whole idea is that this function compares previously measured values to open wire check values, and if there is a significant drop in voltage, cell is allegedly disconnected.

Parameters

cfg	is the BMS configuration struct with constants
bmsData	is an array of 144 cellData structs, containing index, fault, voltage and temperature

Returns

true is the cell is connnected properly, and false if the cell is "disconnected"

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dischargeCellGroups()

bool dischargeCellGroups	(	BMSConfigStructTypedef *	cfg,
		bool	cellDischarge[12][12] )

This function writes the configuration struct of cells that are currently being discharged. This is to track which cells are // being discharged while running our balancing algorithm.

Parameters

cfg	is the configuration struct that stores all the constants in our BMS algorithm
cellDischarge	is a 2D array of cells that tracks which cells are being discharged or not : 1 = discharging, 0 = not discharging returns 0 always -> not sure why we need a return value on this

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initPECTable()

void initPECTable

(

void

)

Initializes Packet Error Code LUT by generating PEC look up table -> call on startup.

Returns

none

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poll_single_secondary_temp_reading()

bool poll_single_secondary_temp_reading	(	uint8_t	board_num,
		BMSConfigStructTypedef *	cfg,
		CellData	bmsData[144] )

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poll_single_secondary_voltage_reading()

bool poll_single_secondary_voltage_reading	(	uint8_t	board_num,
		BMSConfigStructTypedef *	cfg,
		CellData	bmsData[144] )

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readAllCellTemps()

bool readAllCellTemps

(

CellData

bmsData[144]

)

This function reads cell temps from all of our board by calling readCellTemp for each board. NOTE : This is not proven to work properly yet.

Parameters

bmsData

is an array of 144 cellData structs, containing index, fault, voltage and temperature

Returns

true if PEC value received matches expected PEC value. Otherwise, false. -> i.e., returns false if any readCellTemp return values are false.

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readAllCellVoltages()

bool readAllCellVoltages

(

CellData

bmsData[144]

)

This function reads all cell voltages by essentially parsing each board and reading the individual cell voltages. These are then stored in the bmsData array, along with the cell number that is associated with the reading.

Parameters

bmsData

is an array of 144 cellData structs, containing index, fault, voltage and temperature

Returns

true if no PEC for any register read for any board

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readCellTemp()

bool readCellTemp	(	uint8_t	address,
		uint16_t	cellTemp[4],
		bool	dcFault[4],
		bool	tempFault[4] )

This function initiates ADC conversion for GPIO inputs connected to temperature sensors. Reads auxiliary register groups using readRegister function. Then, converts measured voltage into temperature based on temperature sensor response. Also checks for disconnected temperature sensor and OT faults. NOTE: We only read 4 temps per board, and they are the 4 highest temps on each board.

Parameters

address	is the address of the board being read
cellTemp	is the array that will hold the cell temps read during readRegister
dcFault	is the array that stores temperature sensor ceonnection for all cells read
tempFault	stores OT fault info for each cell read

Returns

true if PEC value read matches expected PEC value calculated. Otherwise, false.

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readCellVoltage()

bool readCellVoltage	(	uint8_t	address,
		uint16_t	cellVoltage[12] )

This function sends an ADCV command that begins conversion for every cell to specified LTC. This results in the function readings all cell voltage registers using the readRegister function.

Parameters

address	is the address of the board that will be read
cellVoltage	is the array that will store the voltages of all the cells on the board being read

Returns

true if PEC matches expected PEC value, else false

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readConfig()

bool readConfig	(	uint8_t	address,
		uint8_t	cfg[8] )

This method uses general readRegister function to check current state of LTC configuration reg. Mostly used for testing purposes.

Parameters

address	is the address passed into the readRegister function
cfg	is part of the configuration that will be passed to check the current state of the LTC

Returns

true if the received PEC from readRegister mathes the calculated PEC

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readRegister()

bool readRegister	(	CommandCodeTypedef	command,
		uint8_t	address,
		uint16_t *	data )

Reads register specified by command from specified board address.

Parameters

command	is the command that we will send to the board
address	is the specific board that will get the command
data	is where the data read from the specific board will be StartOpenWireConversionPulldown

Returns

true if the data is valid, otherwise false (i.e., received PEC matches expected PEC value)

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sendAddressCommand()

void sendAddressCommand	(	CommandCodeTypedef	command,
		uint8_t	address )

Sends specified write-only command to LTC with the specified address.

Parameters

command	is the command that will be sent to the LTC
address	is the specified address of the LTC that will receive the command

Returns

none

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sendBroadcastCommand()

void sendBroadcastCommand

(

CommandCodeTypedef

command

)

Sends specified write only command to every LTC in the chain (ex: ADCV)

Parameters

command

contains every command code used

Returns

none

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wakeup_idle()

void wakeup_idle ( )

inline

This function is used to wakeup the LTC chip that we want to use to get readings from.

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writeConfigAddress()

void writeConfigAddress	(	BMSConfigStructTypedef *	cfg,
		uint8_t	address )

this method is used for cellDischarge in order to write configuration datra to the LTC with specified address

Parameters

cfg	is the configuration struct for BMS constants
address	is the address used to pass into our config file

Returns

none

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writeConfigAll()

void writeConfigAll

(

BMSConfigStructTypedef *

cfg

)

This function is called every loop to accommodate dischargeCells method Specifically writes configuration data (UV, OV, ADCMode, etc) to BMSConfig struct.

Parameters

cfg	is the configuration files for the constants in the BMS system

Returns

none

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Variable Documentation

CRC15_POLY

uint16_t CRC15_POLY = 0x4599

pec15Table

uint16_t pec15Table[PEC_TABLE_SIZE]