Introduction

ECAP Signal Monitoring

Each ECAP instance is equipped with 2 signal monitoring units. These signal monitoring units can be configured in one of the 4 following modes.

High Pulse Monitoring Mode -> Rising to Falling
Low Pulse Monitoring Mode -> Falling to Rising
Period Monitoring, Rise edge to Rise edge -> Rising to Rising
Period Monitoring, Fall edge to Fall edge -> Falling to Falling.
Edge Monitoring ( Posedge ) -> Rising Edge : Sync in is mandatory for this mode

Edge Monitoring ( Negedge ) -> Rising Edge : Sync in is mandatory for this mode

For each mode, the CAPEVTs and Stop/Wrap are configured respectively. The Input signal is captured and monitored between Min and Max registers against the Counter value captured with the CAPEVT for the respective mode. Also, these Min and Max registers are 32bit values contain Active-Shadow set. The Shadow to Active loading can be selected to be triggered by either

a Sync event or
a Global Load Strobe event.

Debug Mode is present, for when enabled, the events occuring in the min-max window ranges, the minimum and maximum values within the noted min-max window are captured and stored per monitoring unit.

ECAP Signal Monitoring Summary

Note

The ECAP should be in Absolute mode where no CAPEVT reset the counters for the signal monitoring to be working.
For Edge Monitoring, there needs to be a Sync pulse from an EPWM to reset the monitoring but not restart.
For Pulse or Peroid Monitoring there should not be a Sync in enabled.
The error1 and error2 are used for min window violation error and max window violation error in the monitoring. once these are set, in order to restart the monitoring, one needs to re-enable the monitoring unit and start timestamping on ecap.
On the Edge monitoring modes, the error1 is set for min or max window violation. the error2 is set if there is never an edge between two sync events. For every sync pulse, the edge monitoring restarts.

Example Description

This example configures 3 ECAP moudule, with a total of 6 signal monitoring modules, each with one configuration that are supported. All ECAPs are enabled with Interrupts for the Errors from the Signal Monitoring Modules. An EPWM is configured to provide the input, routed to ECAP via GPI and Inputxbar. This input is varied in a way to cross min and max values from the siganl monitoring modules and the application checks for the interrupt flags are well as the debug range values.

External Connections

AM263PX-CC or AM261X-SOM

No external connection is required.

AM263PX-LP or AM261X-LP

No external connection is required.

Supported Combinations

Parameter	Value
CPU + OS	r5fss0-0 nortos
Toolchain	ti-arm-clang
Boards	am263px-cc, am263px-lp
Example folder	examples/drivers/ecap/ecap_capture_pwm/

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

Sample Output

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

ECAP Signal Monitoring Test Test Started ...
Currently the Input waveform is having all the properties in expected state
 
Pulse Width is modified to exceed bounds
----------------------------------------
    HIGH PULSE Min Bound : 9950 HIGH PULSE Max Bound : 10050    Configured High Pulse Width : 10100
    Observed Min Width : 10000  Observed Max Width : 10050
 
    LOW PULSE Min Bound  : 9950 LOW PULSE Max Bound  : 10050    Configured low Pulse Width  : 9899
    Observed Min Width : 9949   Observed Max Width : 10000
 
Edge Position is modified to exceed bounds
------------------------------------------
    Posedge Min Bound : 4899    Posedge Max Bound : 5099    Configured Posedge Position : 4849
    Observed Min Value : 4900   Observed Max Value : 5004
 
    Negedge Min Bound : 14899   Negedge Max Bound : 15099   Configured Negedge Position : 15149
    Observed Min Value : 15004  Observed Max Value : 15100
 
Period is modified to exceed bounds
-----------------------------------
    Period Min Bound : 19949    Period Max Bound : 20049    Configured Period : 20149
    Observed Min Value on High Period Monitor : 19999   Observed Max Value on High Period Monitor : 20050
    Observed Min Value on Low Period Monitor : 19999    Observed Max Value on Low Period Monitor : 20050
ECAP Signal Monitoring Test Passed!!
All tests have passed!!

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