PSOC™ 4 HV: PACSS on-die temperature measurement

This code example demonstrates on-die temperature measurement using the precision analog channel subsystem (PACSS) delta-V_BE method on the PSOC™ 4 HVPA family devices.

The application measures a 9x/1x current ratio through an internal calibration resistor once at startup, then it continuously measures the on-die temperature by comparing the base-emitter voltage (V_BE) of an internal PNP transistor at two current levels (1x and 9x). Results are printed to the terminal every 500 ms with an 8-sample moving average for noise reduction. The ADC gain is automatically re-calibrated when the temperature drifts by more than 5°C from the last calibration point.

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
PSOC™ 4 HVPA-144K Evaluation Kit (KIT_PSOC4-HVPA-144K_LITE)

Hardware setup

This example uses the board's default configuration. No additional hardware setup is required.

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 If you do not upgrade, you will see an error like "unable to find CMSIS-DAP device" or "KitProg firmware is out of date".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 on-die temperature measurement" application with the desired name "PACSS_ondie_temp" 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-ce242663-pacss-on-die-temp-adc --user-app-name PACSS_ondie_temp --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 current ratio and die temperature measurement results are displayed on the terminal output every 500 ms. The following measurements are displayed:
- Current ratio (9x/1x): Measured once at startup. Ideally close to 9.0
- Die Temp: Instantaneous on-die temperature (°C)
- Die Temp Average (8 samples): Moving-averaged on-die temperature (°C)
Figure 1. Die temperature results in terminal output
The die temperature should reflect the actual on-chip temperature. If the die temperature changes by 5°C from the previous calibration point, ADC gain calibration is automatically re-executed and a re-calibration message is displayed in the terminal

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

Software flow

For the PACSS block initialization, consider the correct startup sequence, which is described in the "Startup timing requirements" section of the architecture reference manual. The Cy_DSADC_Init() function initializes sequencer, ACHAN, DCHAN, and other PACSS functions with correct startup sequence and is called in the cybsp_init() function in the main.c file for this code example

After initialization, the DCHAN2 interrupt is enabled to signal when a conversion result is available. The DCHAN2 gain is calibrated at the assumed initial on-die temperature of 25°C using the Cy_DSADC_CalibrateAchan1_ExtTempTrim() function

The Init_Die_Temp_Sensor() function initializes the die temperature sensor. It copies the DCHAN2 gain level configuration from the Device Configurator output, calculates the bit-shift needed to scale ADC results to the 29-bit signed width expected by the PDL die temperature functions (Cy_DSADC_CalcCurrentRatio() and Cy_DSADC_CalcDieTemp()), and enables the on-die temperature sensor via the Cy_DSADC_EnableTemperature() function

Delta-V_BE measurement method

The on-die temperature sensor uses the delta-V_BE method, a standard CMOS technique for measuring die temperature. The measurement requires four ADC conversions across two phases:

Phase 1: Current ratio calibration (at startup)

Two ADC measurements through an internal 5 kΩ calibration resistor at different current levels (1x = 9.6 μA and 9x = 86.4 μA) determine the actual current ratio. This compensates for the mismatch between the 1x and 9x current sources. GCOR (gain correction) is disabled during these measurements because gain error cancels out in the ratio; OCOR (offset correction) remains enabled for accuracy.

Cy_DSADC_InitializeDieTempConfigs(..., CY_DSADC_TEMPERATURE_MEASUREMENT_RESISTOR)
  → Measure with 1x current (RESISTOR_1X) → dieTempOneCounts
  → Measure with 9x current (RESISTOR_9X) → dieTempUnitCounts
  → currentRatio = Cy_DSADC_CalcCurrentRatio(dieTempOneCounts, dieTempUnitCounts)

Phase 2: Continuous VBE measurement (main loop, every 500 ms)

Two ADC measurements of the base-emitter voltage (V_BE) of an internal PNP transistor at 1x and 9x current levels. The difference (ΔV_BE) is proportional to absolute temperature. Both GCOR and OCOR are disabled for these measurements, as the internal temperature sensor has its own calibration data stored in SFlash.

Cy_DSADC_InitializeDieTempConfigs(..., CY_DSADC_TEMPERATURE_MEASUREMENT_TRANSISTOR)
  → Measure V_BE with 1x current (VBE_1X) → vbeOne
  → Measure V_BE with 9x current (VBE_9X) → vbeUnit
  → temperatureQ12_20 = Cy_DSADC_CalcDieTemp(vbeOne, vbeUnit, currentRatio, PRIMARY)

The Cy_DSADC_CalcDieTemp() function applies a 2nd-order polynomial using factory calibration coefficients from SFlash to convert the normalized ΔV_BE into temperature in Q12.20 fixed-point format (divide by 2²⁰ to obtain °C as a float).

Figure 2. On-die temperature measurement state machine

Note: As shown in Figure 2, the RESISTOR_1X and RESISTOR_9X are executed once at startup for current ratio calibration, while VBE_1X and VBE_9X run continuously in the main loop.

Moving average filter

An 8-sample moving average filter is applied to the calculated die temperature to reduce measurement noise and provide stable temperature tracking. The Calculate_Moving_Average() function maintains a circular buffer of the last 8 temperature results and returns the arithmetic mean.

Auto re-calibration

In the main loop, the moving-averaged die temperature is compared against the previous calibration point. If the temperature changes by more than 5°C, the Cy_DSADC_CalibrateAchan1_ExtTempTrim() function is called to re-calibrate the DCHAN2 gain and offset correction values using the updated die temperature. This ensures that ADC accuracy is maintained across operating temperature variations.

Resources and settings

Table 1. Application resources

Resource	Alias/object	Purpose
UART	CYBSP_UART	UART object used for monitoring die temperature results on terminal
PACSS	PACSS (ACHAN1 / DCHAN2)	Delta-Sigma ADC to measure on-die temperature via internal temperature sensor

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: CE242663 – PSOC™ 4 HV: PACSS on-die temperature measurement

Version	Description of change
1.0.0	New code example

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License

Infineon/mtb-example-ce242663-pacss-on-die-temp-adc

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