Monitor real-time power usage with PAC1954 and TM4C129ENCPDT
The key to sustainable power management
Published Sep 30, 2023
Click board™
PAC1954 Click
Dev. board
Fusion for Tiva v8
Compiler
NECTO Studio
MCU
TM4C129ENCPDT
With our energy monitoring solution, you can effortlessly track your power usage, helping you make informed decisions for a greener future
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Hardware Overview
How does it work?
PAC1954 Click is based on the PAC1954, a four-channel energy monitoring solution with bus voltage monitors and current sense amplifiers that feed high-resolution ADCs from Microchip Technology. Its real-time calibration minimizes offset and gain errors. Built-in 8x averaging feature makes low noise high-resolution measurement results. Four current sense shunt resistors are connected to PAC1954’s integrated current sense amplifier. Electricity is brought to shunts via screw terminals where the middle screw connector represents GND used for bus voltage monitoring. Bus voltage, sense resistor voltage, and accumulated proportional power are stored in registers for retrieval by the MCU. One major feature of the PAC1954 design is a set of digital comparators that allows the user to detect over/under voltage, over/undercurrent, and overpower against user-programmed limits for each channel and generate an alert when the threshold is exceeded. The digital circuitry of the PAC1954 performs power calculations and energy accumulation, which enables energy monitoring with integration periods of up to one year or
longer. After the Start-Up sequence, the PAC1954 is Active and begins sampling the inputs sequentially. Voltage and current are sampled for all active channels at 1024 samples/second by default, and power is calculated and accumulated. PAC1954 Click communicates with MCU using the standard I2C 2-Wire interface to read data and configure settings, supporting Fast Mode operation with a clock frequency up to 1MHz. Besides, it also allows the choice of the least significant bit of its I2C slave address by positioning the SMD jumper labeled ADDR SEL to an appropriate position marked as 0 and 1. The Power-Down pin, labeled as EN and routed to the CS pin of the mikroBUS™ socket, optimizes power consumption and is used for power on/off purposes. All circuits, including the interface pins, are inactive in this state, and the PAC1954 is in the form of minimum power dissipation. The SLW pin, routed to the RST pin of the mikroBUS™ socket, serves as the conversion rate control. If the SLW pin is asserted, the sample rate is eight samples per second. For sampling rates lower than 1024 samples/second, the PAC1954 is in Sleep mode for
a portion of the conversion cycle, which results in lower power dissipation. No matter the programmed sample rate, this new sample rate will affect the following conversion cycle. The alert functionality, routed to the INT pin of the mikroBUS™ socket, has multiple purposes: to notify the system that a conversion cycle for all active channels is complete, or to inform the system that the accumulator or accumulator count has overflowed, or that an electrical parameter is outside the programmed limit. Besides the INT pin, the SLW pin can function as another alert feature by attaching a pull-up resistor to it, which is done via an onboard SMD jumper labeled as SLW PULL by positioning a 10k resistor to an appropriate position marked as DOWN or UP. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used as a reference for further development.
Features overview
Development board
Fusion for TIVA v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of microcontrollers, such as different 32-bit ARM® Cortex®-M based MCUs from Texas Instruments, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over a WiFi network. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, Fusion for TIVA v8 provides a fluid and immersive working experience, allowing access
anywhere and under any circumstances at any time. Each part of the Fusion for TIVA v8 development board contains the components necessary for the most efficient operation of the same board. An advanced integrated CODEGRIP programmer/debugger module offers many valuable programming/debugging options, including support for JTAG, SWD, and SWO Trace (Single Wire Output)), and seamless integration with the Mikroe software environment. Besides, it also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.
Communication options such as USB-UART, USB HOST/DEVICE, CAN (on the MCU card, if supported), and Ethernet is also included. In addition, it also has the well-established mikroBUS™ standard, a standardized socket for the MCU card (SiBRAIN standard), and two display options for the TFT board line of products and character-based LCD. Fusion for TIVA v8 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.
Microcontroller Overview
MCU Card / MCU
Type
8th Generation
Architecture
ARM Cortex-M4
MCU Memory (KB)
1024
Silicon Vendor
Texas Instruments
Pin count
128
RAM (Bytes)
262144
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Fusion for Tiva v8 as your development board.
Track your results in real time
Application Output
1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.
2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.
3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.
Software Support
Library Description
This library contains API for PAC1954 Click driver.
Key functions:
pac1954_refresh_cmd- This function updates the readable registers for the VBUS, VSENSE, Power, accumulator outputs and accumulator count by issuing the REFRESH commandpac1954_get_calc_measurement- This function calls the function for getting the selected measurement data and performs all the necessary calculations to get the measurement value in standard unitpac1954_generic_write- This function writes a desired number of data bytes starting from the selected register by using I2C serial interface.
Open Source
Code example
The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.
/*!
* @file main.c
* @brief PAC1954 Click example
*
* # Description
* This example demonstrates the use of PAC1954 Click board.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and performs the Click default configuration.
*
* ## Application Task
* Reads the voltage, current, and power from Channel 1 and displays all
* values on the USB UART once per second.
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "pac1954.h"
static pac1954_t pac1954;
static log_t logger;
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
pac1954_cfg_t pac1954_cfg; /**< Click config object. */
/**
* Logger initialization.
* Default baud rate: 115200
* Default log level: LOG_LEVEL_DEBUG
* @note If USB_UART_RX and USB_UART_TX
* are defined as HAL_PIN_NC, you will
* need to define them manually for log to work.
* See @b LOG_MAP_USB_UART macro definition for detailed explanation.
*/
LOG_MAP_USB_UART( log_cfg );
log_init( &logger, &log_cfg );
log_info( &logger, " Application Init " );
// Click initialization.
pac1954_cfg_setup( &pac1954_cfg );
PAC1954_MAP_MIKROBUS( pac1954_cfg, MIKROBUS_1 );
err_t init_flag = pac1954_init( &pac1954, &pac1954_cfg );
if ( I2C_MASTER_ERROR == init_flag )
{
log_error( &logger, " Application Init Error. " );
log_info( &logger, " Please, run program again... " );
for ( ; ; );
}
pac1954_default_cfg ( &pac1954 );
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
float vsource = 0;
float isense = 0;
float power = 0;
pac1954_refresh_cmd ( &pac1954 );
pac1954_get_calc_measurement ( &pac1954, PAC1954_MEAS_SEL_V_SOURCE,
PAC1954_CH_SEL_CH_1,
PAC1954_AVG_SEL_ENABLE,
PAC1954_MEAS_MODE_BIPOLAR_FSR,
&vsource );
pac1954_get_calc_measurement ( &pac1954, PAC1954_MEAS_SEL_I_SENSE,
PAC1954_CH_SEL_CH_1,
PAC1954_AVG_SEL_ENABLE,
PAC1954_MEAS_MODE_BIPOLAR_FSR,
&isense );
pac1954_get_calc_measurement ( &pac1954, PAC1954_MEAS_SEL_P_SENSE,
PAC1954_CH_SEL_CH_1,
0,
PAC1954_MEAS_MODE_BIPOLAR_FSR,
&power );
log_printf( &logger, " Voltage: %.3f V\r\n", vsource );
log_printf( &logger, " Current: %.3f A\r\n", isense );
log_printf( &logger, " Power: %.3f W\r\n", power );
log_printf( &logger, "---------------------------\r\n" );
Delay_ms ( 1000 );
}
int main ( void )
{
/* Do not remove this line or clock might not be set correctly. */
#ifdef PREINIT_SUPPORTED
preinit();
#endif
application_init( );
for ( ; ; )
{
application_task( );
}
return 0;
}
// ------------------------------------------------------------------------ END
