ADC PPB Delay

Table of Contents

• Introduction
  • Example Description
    • Note
  • SOC Configurations
  • PPB Configurations
  • Interrupt Configurations
  • ISR configurations
  • EPWM Configurations
• External Connections
  • AM263Px-CC E2 or AM263x-CC E2
  • AM263x-CC E1
  • AM263Px-LP or AM263x-LP
• Watch Variables
• Supported Combinations
• Steps to Run the Example
• See Also
• Sample Output

Introduction

Example Description

This example demonstrates the PPB delay time stamp feature of the ADC. The PPBs (Post Processing Blocks) in ADC offer timestamping the delay between the conversion of given SOC and the trigger(associated) occurrence.

Delay Measurement

Note

• if a trigger occurred and the conversion occurred immediately, i.e., without any delay, the PPB captures a value '2'. and contains '0' as reset value. Hence, 0 in Delay represents SOC hasn't converted or there is an overflow of Delay counter.

SOC Configurations

1. SOC 0 :
   1. Trigger is set to EPWM0SOCA.
   2. Sample window : 17
   3. Samples on Channel 0 (arbitrary)
2. SOC 1 :
   1. Trigger is set to EPWM1SOCA.
   2. Sample window : 17
   3. Samples on Channel 1 (arbitrary)

PPB Configurations

1. PPB 1 is set for SOC 0
2. PPB 2 is set for SOC 1

Interrupt Configurations

INT xbar0, INT xbar1 are set for ADC 1 INT 1 and ADC 1 INT 2 respectively.

1. ADC 1 INT 1 :
   • triggered by EOC/SOC0
   • triggers ISR App_adcISR0()
2. ADC 1 INT 2 :
   • triggered by EOC/SOC1
   • triggers ISR App_adcISR1()

ISR configurations

1. App_adcISR0 :
   • reads the delays in SOC0 and SOC1.
   • clears the INT 1 flag
2. App_adcISR1 :
   • clears the INT 1 flag

EPWM Configurations

1. EPWM 0 :
   • TimeBase Period is set to 2048.
   • Generates EPWM0SOCA when the TimeBase counter equals TimeBase Period.
   • Counter Mode will be set to Up-count mode in the example.
2. EPWM 1 :
   • TimeBase Period is set to 9999.
   • Generates EPWM1SOCA when the TimeBase Counter equals TimeBase Period.
   • Counter Mode will be set to Up-count mode in the example.

External Connections

AM263Px-CC E2 or AM263x-CC E2

Feed analog inputs to channels

• ADC1_AIN0 - HSEC Pin 12
• ADC1_AIN1 - HSEC Pin 14

AM263x-CC E1

Feed analog inputs to channels

• ADC1_AIN0 - HSEC Pin 18
• ADC1_AIN1 - HSEC Pin 20

AM263Px-LP or AM263x-LP

Feed analog inputs to channels

• ADC1_AIN0 - J1/3 Pin 24
• ADC1_AIN1 - J1/3 Pin 29

Watch Variables

• gAdc1soc0Delay[] - holds the delay values for ADC1_SOC0
• gAdc1soc1Delay[] - holds the delay values for ADC1_SOC1

Supported Combinations

Parameter	Value
CPU + OS	r5fss0-0 nortos
Toolchain	ti-arm-clang
Board	am263x-cc, am263x-lp
Example folder	examples/drivers/adc/adc_ppb_delay/

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.
• Observe 6 EPWM waveforms. After ADC input voltage exceeds the PPB limit, PWMs get tripped.

See Also

ADC

Sample Output

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

ADC PPB Delay Test Started
Delays associated with
conversion  SOC 0   SOC 1
    16      13      2
    24      2       18
    41      35      2
    66      57      2
    91      2       41
    108     12      2
    116     2       19
    133     34      2
    158     56      2
    183     2       42
    200     11      2
    208     2       20
    225     33      2
    250     55      2
ADC PPB Delay Test Passed
All tests have passed!!