STSW-L9961BMS Software Package for STEVAL-L99614C Kit User Guide

: June 12, 2024
: ST

STSW-L9961BMS Software Package for STEVAL-L99614C Kit

Software package for the STEVAL-L99614C kit -L9961 industrial battery management system

STSW-L9961BMS Software Architecture

Main SW functional layers are:

Hardware abstraction divided in
● STM32CubeG0 HAL and LL Hardware Abstraction Layer for the STM32G0 microcontroller.
● Board Support Package (BSP) library layer
containing the drivers of:
● the L9961 component device,
● the STEVAL-L99615C expansion board,
● the NUCLEO-G071RB board.
Application
● Battery status monitoring demonstrating the acquisition of voltage, current and temperature from a battery pack made up of 5 cells.

Applications & demonstration| Battery status monitoring(voltage, current and temperature)
---|---
Board Support Package Hardware Abstraction| L9961 Component| STEVAL-L99615C BSP| NUCLEO-G071RB BSP
STM32CubeG0 HAL / LL
Hardware| STM32G071RB| L9961|
L9961

Key topics of the STSW-L9961BMS Software package

Application demo examples exploiting the key-features of the L9961 BMS ICs.
L9961 component Driver, including both its register map and the related basic APIs.
Source FW package compatible with STM32Cube Firmware BSP Specification.
Use of a serial communication terminal for output data.
Contains demonstration project released for:
STM32CubeIDE v.1.12
EWARM (IAR) v. 9.20
uVision (Keil) v. 5.38

Application Demo 1 features

STSW-L9961BMS: BSP drivers

The Board Support Package comprises the following drivers:

the L9961 component device, including the register map of the device, the basic functions to manage registers at bit level, the write/read functions (single-register and multi-registers), and the APIs to configure the device and manage its functionalities (i.e. Go-to Normal, Change Address, Enable/Disable CRC,…).
the STEVAL-L99615C expansion board support package that manages the configurations of the HW peripheral and GPIOs used by the application.
the NUCLEO-G071RB Nucleo board support package containing a set of minor functions connected to the microcontroller board.

STSW-L9961BMS: Application Demo (#1)

The Demo 1 is fully described by the Application User source and header files provided in the Core folder.

The demo operates acquiring:
- the voltage on each cell,
- the voltage on the whole battery pack,
- the current flowing in the cell series,
- the temperature acquired by the NTC,
- the temperature measured on the die.

The demo outputs these acquired data through a serial communication terminal.

STEVAL-L99615C Kit Overview

STEVAL-L99615C evaluation kit

Demonstrating L9961 BMS IC performances and features with external 5-cell battery pack or with onboard pack simulation
Kit composition:
- STEVAL-L99615C: NUCLEO-G071RB development board with STM32G071RB MCU + STEVAL-L99615CX expansion board integrating the L9961 5-cell BMS IC
- STSW-L99615C (* ) SW GUI uses the PC serial communication to interface with the STM32 microcontroller and L9961
- STSW-L9961BMS (* ) SW package, containing source code and binaries, with standalone FW driver and application examples
  STEVAL-L99615C
  
  the GUI contained in the STSW-L96615C is exclusive to the FW contained in the same SW package and cannot be used with the one of the STSW-L9961BMS packages

STEVAL-L99615C at a glance!

Setup & programming the kit

Application Demo 1 setup

To set up the demo and run the application with the evaluation kit, the following items are required:

a STEVAL-L99615C kit;
the STSW-L9961BMS software package;
a USB Type-A to Micro-B cable;
a portable power supply(* ) (for example, up to 20 V, 1 A) to feed the STEVAL-L99615C kit (** ) (in case a real battery is not available);
a laptop with the serial communication terminal already installed (for this example we selected PuTTY console).

*( ) : to run the Application Demo 1, it is assumed to use the 5-cell battery emulating circuitry embedded in the expansion board, coupled with the external power supply that simulates the battery voltage.
( ) : to facilitate the connection of the power supply, equip it with a two or four position plug 7.62MM connector as the Wurth 691351400002 or 691351400004.

Application Demo 1: kit jumpers setup

Verify that the setting of the STEVAL-L99615C jumpers respects the configuration depicted in the picture and reported in the following Table.

Name	Board	Description	Configuration
J1	EXP. BOARD	Used to measure current flowing into VB Closed pin	Closed
J2	EXP. BOARD	VIO voltage selector	2-3: 3.3 V from L9961 (VREG)
J4	EXP. BOARD	Used to select micro power source	Closed
J5	EXP. BOARD	Battery simulator – used to simulate Note : It i _s
assumed that 5-_ battery pack	**Closed _

How the STEVAL-L99615C emulates a 5-cell battery pack

hanks to its design, the STEVAL-L99615C permits to simulate a 5-cell battery pack simply applying a voltage, by an external power supply, to the CN2 connector.
In fact, a network composed of a series of 5 resistance/capacitance parallel, integrated in the kit expansion board, acts by emulating the 5 cells of a battery pack.
When voltage is applied, it is equally distributed by the series. Thus, the Application Demo 1 acquires the voltages on each resistance representing the Cell voltages (Vcell1, …, Vcell5).
To enable the internal 5-cell emulation network, verify the headers are fit on the J5 jumpers in the STEVAL-L99615C expansion board.

How the STEVAL-L99615C emulates the NTC acquisition

For demonstrating how the L9961 measures the temperature of a battery pack via NTC, the STEVAL-L99615C embeds a variable resistor (referred to the internal LDO voltage).
That permits to emulate how the resistor value changes (actually through a screwdriver) to a hypothetical temperature change.
So, as a standard NTC, the decrease of electrical resistance value (mechanically happens) corresponding to the acquired voltage decrease, may be referred to the temperature rising.
Vice versa, the increase of the resistance value corresponding to the acquired voltage decrease refers to the temperature decrease.
This mechanism also enables the demonstration of over/under temperature detection operation carried out by the L9961

Application Demo 1: power up

Connect the STEVAL-L99615C kit to the laptop using the USB Type-A to Micro-B cable.
Connect the power supply terminals to the B+ and B- pins of the battery pack connector (CN2), and power on the appliance (in the example, the power supply has been set 12 V, 1 A as test rating).

Application Demo 1: programming

Drag and drop the binary file of the STSW-L9961BMS application firmware(* ) , from the origin folder to the NUCLEO that has been mapped by the laptop OS as an external peripheral.
This operation permits to directly program the on-board STM32G071RB microcontroller of the NUCLEOG071RB.

Application Demo 1: running

Once programmed, open the serial communication console to display the result of the data acquisition by the application
demo 1.

Application Demo 1: Output messages in Normal acquisition

The first character represents the status of the application (N stands for NORMAL while F stands for Fault.
The 5 Cell voltages VCells represent the acquisition of the voltage on the battery cell emulation
VcellSum represents the sum value released by the L9961 after acquiring the Vcells, while VB is the value directly acquired on the battery pack (in our example VB is the power supply voltage).
Curr represents the current flowing from/on the battery pack (null if no load connected)
Temperature is dually released, by the external NTC and by the DIE internal sensor (DieTemp).

Application Demo 1: Output messages in Fault acquisition

Application Demo 1 has been set to release an Alert message when relevant events occur (for example, when the NTC Over Temperature Threshold is exceeded).
In fact, turning the NTC screw clockwise, its value decreases and when it reaches 900mV, the demo releases a Fault message indicating the cause (NTC_OT), while the first character of the string becomes F.
Turning counterclockwise, till the NTC value exceeds the 900mV, a new message indicating the fault cleaned, is released and the first character of the string goes back to N.

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