PSOC™ 4 HV: PACSS wakeup from DeepSleep

This code example demonstrates the use of the precision analog channel subsystem (PACSS) ADC for current measurement while periodically entering and waking from DeepSleep mode on PSOC™ 4 HVPA family devices.

The application alternates between Active and DeepSleep modes. In Active mode, the PACSS ADC continuously measures the voltage across an onboard shunt resistor and calculates the current. In DeepSleep mode, the watchdog timer (WDT) generates a periodic interrupt (~1 second) to wake the CPU, after which a single measurement is taken before returning to DeepSleep mode. This pattern demonstrates ultra-low-power periodic sensing for battery-powered or energy-harvesting applications.

View this README on GitHub.

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Requirements

ModusToolbox™ v3.7 or later (tested with v3.7)
Board support package (BSP) minimum required version: 3.1.0
Programming language: C
Associated parts: PSOC™ 4 HV MCU

Supported toolchains (make variable 'TOOLCHAIN')

GNU Arm® Embedded Compiler v14.2.1 (GCC_ARM) – Default value of TOOLCHAIN
Arm® Compiler v6.22 (ARM)
IAR C/C++ Compiler v9.50.2 (IAR)

Supported kits (make variable 'TARGET')

PSOC™ 4 HVPA-SPM 1.0 Evaluation Kit (KIT_PSOC-HVPA-SPM1_LITE) – Default value of TARGET

Hardware setup

This example uses the board's default configuration. See the kit user guide to ensure that the board is configured correctly.

Note: Some of the PSOC™ 4 HV kits ship with KitProg2 installed. ModusToolbox™ requires KitProg3. Before using this code example, make sure that the board is upgraded to KitProg3. The tool and instructions are available in the Firmware Loader GitHub repository. If you do not upgrade, you will see an error like "unable to find CMSIS-DAP device" or "KitProg firmware is out of date".

Software setup

See the ModusToolbox™ tools package installation guide for information about installing and configuring the tools package.

Install a terminal emulator if you do not have one. Instructions in this document use Tera Term.

This example requires no additional software or tools.

Using the code example

Create the project

The ModusToolbox™ tools package provides the Project Creator as both a GUI tool and a command line tool.

Use Project Creator GUI

Open the Project Creator GUI tool

There are several ways to do this, including launching it from the dashboard or from inside the Eclipse IDE. For more details, see the Project Creator user guide (locally available at {ModusToolbox™ install directory}/tools_{version}/project-creator/docs/project-creator.pdf)
On the Choose Board Support Package (BSP) page, select a kit supported by this code example. See Supported kits

Note: To use this code example for a kit not listed here, you may need to update the source files. If the kit does not have the required resources, the application may not work
On the Select Application page:

a. Select the Applications(s) Root Path and the Target IDE

Note: Depending on how you open the Project Creator tool, these fields may be pre-selected for you

b. Select this code example from the list by enabling its check box

Note: You can narrow the list of displayed examples by typing in the filter box

c. (Optional) Change the suggested New Application Name and New BSP Name

d. Click Create to complete the application creation process

Use Project Creator CLI

The 'project-creator-cli' tool can be used to create applications from a CLI terminal or from within batch files or shell scripts. This tool is available in the {ModusToolbox™ install directory}/tools_{version}/project-creator/ directory.

Use a CLI terminal to invoke the 'project-creator-cli' tool. On Windows, use the command-line 'modus-shell' program provided in the ModusToolbox™ installation instead of a standard Windows command-line application. This shell provides access to all ModusToolbox™ tools. You can access it by typing "modus-shell" in the search box in the Windows menu. In Linux and macOS, you can use any terminal application.

The following example clones the "PACSS wakeup from DeepSleep" application with the desired name "PACSS_wakeup_from_DeepSleep" configured for the KIT_PSOC-HVPA-SPM1_LITE BSP into the specified working directory, C:/mtb_projects:

project-creator-cli --board-id KIT_PSOC-HVPA-SPM1_LITE --app-id mtb-example-ce242660-pacss-deepsleep-wakeup --user-app-name PACSS_wakeup_from_DeepSleep --target-dir "C:/mtb_projects"

The 'project-creator-cli' tool has the following arguments:

Argument	Description	Required/optional
`--board-id`	Defined in the field of the BSP manifest	Required
`--app-id`	Defined in the field of the CE manifest	Required
`--target-dir`	Specify the directory in which the application is to be created if you prefer not to use the default current working directory	Optional
`--user-app-name`	Specify the name of the application if you prefer to have a name other than the example's default name	Optional

Note: The project-creator-cli tool uses the git clone and make getlibs commands to fetch the repository and import the required libraries. For details, see the "Project creator tools" section of the ModusToolbox™ tools package user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mtb_user_guide.pdf).

Open the project

After the project has been created, you can open it in your preferred development environment.

Eclipse IDE

If you opened the Project Creator tool from the included Eclipse IDE, the project will open in Eclipse automatically.

For more details, see the Eclipse IDE for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_ide_user_guide.pdf).

Visual Studio (VS) Code

Launch VS Code manually, and then open the generated {project-name}.code-workspace file located in the project directory.

For more details, see the Visual Studio Code for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_vscode_user_guide.pdf).

Arm® Keil® µVision®

Double-click the generated {project-name}.cprj file to launch the Keil® µVision® IDE.

For more details, see the Arm® Keil® µVision® for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_uvision_user_guide.pdf).

IAR Embedded Workbench

Open IAR Embedded Workbench manually, and create a new project. Then select the generated {project-name}.ipcf file located in the project directory.

For more details, see the IAR Embedded Workbench for ModusToolbox™ user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mt_iar_user_guide.pdf).

Command line

If you prefer to use the CLI, open the appropriate terminal, and navigate to the project directory. On Windows, use the command-line 'modus-shell' program; on Linux and macOS, you can use any terminal application. From there, you can run various make commands.

For more details, see the ModusToolbox™ tools package user guide (locally available at {ModusToolbox™ install directory}/docs_{version}/mtb_user_guide.pdf).

Operation

Connect the board to your PC using the provided USB cable through the KitProg3 USB connector
Open a terminal program and select the KitProg3 COM port. Set the serial port parameters to 8N1 and 115200 baud
Program the board using one of the following:
Using Eclipse IDE
1. Select the application project in the Project Explorer
2. In the Quick Panel, scroll down, and click <Application Name> Program (KitProg3_MiniProg4)
In other IDEs

Follow the instructions in your preferred IDE.
Using CLI

From the terminal, execute the make program command to build and program the application using the default toolchain to the default target. The default toolchain is specified in the application's Makefile but you can override this value manually:
```
make program TOOLCHAIN=<toolchain>
```
Example:
```
make program TOOLCHAIN=GCC_ARM
```
After programming, the application starts automatically. Confirm that the terminal shows alternating ACTIVE mode and DEEPSLEEP mode sections, each containing five measurement results. Each result displays the input voltage across the shunt resistor in millivolts and the calculated current in milliamps

Figure 1. Terminal output showing Active and DeepSleep measurement results
Verify that the current values are consistent between Active and DeepSleep modes. The DeepSleep measurements are taken once per second (triggered by the WDT periodic interrupt), while the Active mode measurements are taken continuously

Debugging

You can debug the example to step through the code.

In Eclipse IDE

Use the <Application Name> Debug (KitProg3_MiniProg4) configuration in the Quick Panel. For details, see the "Program and debug" section in the Eclipse IDE for ModusToolbox™ user guide.

In other IDEs

Follow the instructions in your preferred IDE.

Design and implementation

Overview

This code example demonstrates how the PACSS ADC can operate across Active and DeepSleep power modes on the PSOC™ 4 HVPA family. The application performs shunt resistor current measurement, alternating between:

Active mode: Continuous PACSS ADC sampling with Automatic Gain Control (AGC) enabled
DeepSleep mode: CPU sleeps and is periodically woken by the WDT (~1 second interval) to take a single measurement

Figure 2. Software flowchart

Initialization

The PACSS block requires a specific startup sequence described in the "Startup timing requirements" section of the architecture reference manual. Cy_DSADC_Init() initializes the sequencer, ACHAN, DCHAN, AGC, and HPBGR with the correct startup sequence and is called in cybsp_init().

After peripheral initialization:

The DCHAN0 data-valid interrupt is enabled to set a flag when a conversion result is ready
Gain and offset correction values are calibrated using factory calibration data stored in SFlash, assuming an on-die temperature of 25°C
The WDT is configured with a warn limit of 32767 counts at PILO 32.768 kHz, generating an interrupt approximately every 1 second. Auto-service is enabled to automatically clear the counter. The WDT counter continues running during DeepSleep (CY_WDT_DISABLE for DeepSleep pause), enabling it to serve as the wakeup source

Active mode operation

In Active mode, the PACSS ADC is configured for continuous measurement:

ACHAN0 and AGC are enabled, and AREF low power mode is disabled via Arrange_Active_Mode()
Conversion is started with Cy_DSADC_StartConversionAchan() as a software trigger
The first several measurement results (equal to the number of FIR taps) are discarded in Settle_FIR_filter() to allow the FIR filter to settle
Five valid samples are read. For each sample, the ISR sets the g_currentDataValid flag, and the main loop reads the result and prints the voltage and calculated current

DeepSleep mode operation

In DeepSleep mode, the CPU enters into low-power sleep and wakes up periodically:

Before entering DeepSleep (Arrange_Deepsleep_Mode()):
- The sequencer is disabled
- AGC is disabled and ACHAN0 is disabled to reduce power
- AREF low power mode is enabled (Cy_DSADC_EnableLowPowerMode())
- The sequencer is re-enabled. The PACSS block remains partially powered so it can restart quickly after wakeup
Entering DeepSleep: Cy_SysPm_CpuEnterDeepSleep() puts the CPU into DeepSleep mode. The CPU halts until the WDT interrupt fires
After wakeup (Process_Wakeup_Sequence()):
- A 1000 µs delay allows the high precision bandgap reference (HPBGR) to settle
- ACHAN0 is re-enabled
- A 60 µs delay allows the anti-aliasing filter (AAF) to settle
- Conversion is started and the FIR filter is settled by discarding initial samples
- One valid measurement is taken and printed
This cycle repeats 5 times before switching back to Active mode

Measurement and current calculation

The PACSS ADC measures the differential voltage across the onboard shunt resistor (RSH_0 / RSL_0 pins). The raw ADC result is converted to millivolts using Cy_DSADC_CountsTo_mVolts(), and the current is calculated using Ohm's law:

$I = \frac{V_{shunt}}{R_{shunt}}$

Where $R_{shunt}$ = 4.02 Ω

PACSS ADC configuration

Table 1. PACSS ADC configuration

Parameter	Value
DSM clock	3 MHz (IMO 24 MHz/8)
Stage 1 decimation ratio	64
Stage 2 decimation ratio	6
Decimation mode	SINC3
FIR filter	16-tap symmetric
AGC gain levels	9 levels (2x – 512x)
VREFH	HPBGR 1.2 V
Averaging	4 samples
Input mux	Positive: RSH_0, Negative: RSL_0
Conversion mode	Continuous

WDT configuration

Table 2. WDT configuration

Parameter	Value
Clock source	PILO (32.768 kHz)
Warn limit	32767 (0x7FFF)
Warn action	Interrupt
Upper limit	32768 (0x8000)
Upper action	None
Auto service	Enabled
DeepSleep pause	Disabled (counter keeps running)
Wakeup period	~1 second

Resources and settings

Table 3. Application resources

Resource	Alias/object	Purpose
UART (SCB0)	CYBSP_UART	UART object used for monitoring ADC result on terminal (115200 baud, 8N1)
PACSS (DSADC)	PACSS	Delta-Sigma ADC to measure input voltage across shunt resistor
WDT	WDT	Watchdog Timer used as periodic wakeup source from DeepSleep (~1 sec interval)

Related resources

Resources	Links
Application notes	AN230264 – Getting started with PSOC™ HVPA family AN230370 – Precision analog channel subsystem in PSOC™ 4 HVPA family AN0034 – Getting started with PSOC™ 4 HVMS and PSOC™ 4 HVPA MCUs in ModusToolbox™
Code examples	Using ModusToolbox™ on GitHub
Device documentation	PSOC™ 4 HVPA datasheets PSOC™ 4 HVPA MCU reference manuals
Development kits	Select your kits from the Evaluation board finder
Libraries on GitHub	mtb-pdl-cat2 – PSOC™ 4 Peripheral Driver Library (PDL) mtb-hal-cat2 – Hardware Abstraction Layer (HAL) library
Tools	ModusToolbox™ – ModusToolbox™ software is a collection of easy-to-use libraries and tools enabling rapid development with Infineon MCUs for applications ranging from wireless and cloud-connected systems, edge AI/ML, embedded sense and control, to wired USB connectivity using PSOC™ Industrial/IoT MCUs, AIROC™ Wi-Fi and Bluetooth® connectivity devices, XMC™ Industrial MCUs, and EZ-USB™/EZ-PD™ wired connectivity controllers. ModusToolbox™ incorporates a comprehensive set of BSPs, HAL, libraries, configuration tools, and provides support for industry-standard IDEs to fast-track your embedded application development

Other resources

Infineon provides a wealth of data at www.infineon.com to help you select the right device, and quickly and effectively integrate it into your design.

Document history

Document title: CE242660 – PSOC™ 4 HV: PACSS wakeup from DeepSleep

Version	Description of change
1.0.0	New code example

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License

Infineon/mtb-example-ce242660-pacss-deepsleep-wakeup

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