Safety Checker module

The safety checker module provides the ability to compare ADC conversion results for safety critical application. It is divided into two parts: Safety checker tiles and Safety checker aggregator. Safety checker tile captures conversion results from multiple ADc modules and compares the absolute value of the difference to the configured tolerance. While Safety checker aggregator takes the computed data and genreate a trip event signal if the result is out of range. The trip event can be sent to INT XBAR and an ISR can be triggered.

ADC Safety Checker Tile Diagram

Example Description

This example compares the absolute value of the two ADC conversion results with the set tolerance value and generates an out-of-tolerance flag if the difference exceeds the tolerance value. Channel 0 and 1 of ADC1 are used to compare the two ADC conversion. If the difference between two conversion results exceeds the value configured as tolerance then the ADC safety checker aggregator generates an interrupt signal from out-of-tolerance.

Safety Checker Configurations

Safety checker tile 1 is configured to compare two ADC channels ADC1_AIN0 and ADC1_AIN1
The tolerance value is set to 100 in digital representation
- If the difference between two ADC channel is > 100, it will generate an interrupt
Safety checker aggregator is configured to generate an interrupt when oot event occures

Watch Variables

gAdc1Result0[], gAdc1Result1[] - the digital representation of the Analog signal on ADC1_AIN0 and ADC1_AIN1.
count - the number of times the OOT flag is generated.

External Connections

ADC1_AIN0, ADC1_AIN1 pins should be connected to signals to be converted

on AM263Px CC E1 or AM261x SOM E1, with HSEC Dock
- Feed Analog input to ADC1_AIN0 - HSEC PIN 12
- Feed Analog input to ADC1_AIN1 - HSEC PIN 14
on AM263Px LP
- Feed Analog input to ADC1_AIN0 - J1/3 Pin 24
- Feed Analog input to ADC1_AIN1 - J1/3 Pin 29
on AM261x LP
- Feed Analog input to ADC1_AIN0 - J1/3 Pin 24
- Feed Analog input to ADC1_AIN1 - J5/7 Pin 42

Supported Combinations

Parameter	Value
CPU + OS	r5fss0-0 nortos
Toolchain	ti-arm-clang
Board	am263px-cc, am263px-lp
Example folder	examples/drivers/adc/adc_safety_checker/

Steps to Run the Example

When using CCS projects to build, import the CCS project for the required combination and build it using the CCS project menu (see Using SDK with CCS Projects).
When using makefiles to build, note the required combination and build using make command (see Using SDK with Makefiles)
Establish connections as mentioned in External Connections section.
Launch a CCS debug session and run the executable, see CCS Launch, Load and Run
Using the watch variables, view the ADC conversion results.
View the ADC conversion results in UART console logs

Sample Output

Shown below is a sample output when the application is running,

ADC Safety Checker Test Started ...
ADC 1 Channel 0     ADC 1 Channel 1     Safety Check OOT Flag
    4095                0                   1
    4095                0                   1
    4095                0                   1
    4095                0                   1
    4095                0                   1
    4095                0                   1
    4095                0                   1
    4095                0                   1
    4095                0                   1
    4095                0                   1
ADC OOT Flag Count 10
ADC Safety Checker Test Passed!!
All tests have passed!!

Table of Contents