AM263P4-Q1: AM263P4-eCAP Module integration

Hi Jayakeerthana,

The eCAP module can accurately capture PWM characteristics. If a mismatch or fault is detected, MCU B can notify MCU A via SPI.

Refer to the information in the example at the link below:

EXAMPLES_DRIVERS_ECAP_CAPTURE_PWM.html

Implementation:

1. Signal Routing: Connect MCU A’s PWM output to an eCAP input pin on MCU B. Route the signal through the Input X-BAR to the eCAP module's CAP_IN input, configuring the 256:1 input multiplexer (ECCTL0.INPUTSEL).

2. eCAP Configuration: Configure the eCAP module in capture mode:

   • Use the 32-bit time base counter for timestamping PWM edges.
   • Capture both rising and falling edges for precise timing.
   • Utilize the four event time-stamp registers.
   • Enable signal monitoring for fault detection.

3. Fault Detection: The eCAP module's signal monitoring functionality detects PWM mismatches. Configure it to define what constitutes a fault.

4. Fault Reporting via SPI:

   • Trigger: Use the eCAP’s TRIP_OUT signal or CAP_INT interrupt when a fault is detected.
   • SPI Communication: In the ISR (triggered by interrupt or TRIP_OUT), initiate an SPI transaction. MCU B acts as the controller initiating communication with MCU A (the peripheral).
   • Data Transmission: Send a fault flag or status code to MCU A through SPI. For example: SPI_Send_Fault_Flag(FAULT_CODE).
   • Error Handling: Implement SPI error checks to ensure successful transmission.

Component Summary:

Key Considerations:

• Timing: Ensure the PWM signal meets the eCAP’s timing requirements for reliable capture.
• Synchronization: Synchronize eCAP capture events with SPI transmission.
• SPI Latency: Account for SPI latency in the fault response time.
• Input Line State: Consider pull-up/pull-down resistors on the eCAP input pin.

Best Regards,

Zackary Fleenor

Hi Jayakeerthana,

The AM263P4 documentation separates primary pin multiplexing information from secondary peripheral routing details. The Pin Attributes table in the datasheet defines the SoC pin multiplexed signal function implemented at the pin but does not define secondary multiplexing of signal functions implemented in device subsystems. For secondary multiplexed signal functions like eCAP routing, you must refer to the respective peripheral chapter of the device TRM.

eCAP Input Configuration via Input XBAR

The eCAP module's capture inputs are connected using the Input XBAR, as mentioned on page 917 of the TRM [2]. The eCAP module uses a 256:1 input multiplexer for its input selection.

Specific Reference Location: The detailed information about eCAP input selection can be found on page 783 of the TRM (SPRUJ55D). This section provides the complete mapping of how eCAP inputs connect through the Input XBAR.

eCAP Input Selection Mapping

The following table shows the available INPUTXBAR outputs that can be routed to eCAP inputs:

Configuration Approach

To configure eCAP routing for your application:

1. First, configure the desired GPIO pin's primary multiplexing using the Pin Attributes table in the datasheet
2. Then, use the Input XBAR to route that GPIO signal to one of the INPUTXBAR.OUT1-31 outputs
3. Finally, select the appropriate INPUTXBAR output (using the select index 203-233) as the eCAP input source

The Input XBAR chapter (page 917) will provide details on how to configure GPIO pins as inputs to the XBAR, while the eCAP chapter (page 783) shows how to select the XBAR output as the eCAP capture input.

Citations

1. AM263P4 Datasheet - Pin Attributes Documentation Structure
2. AM263P4 Technical Reference Manual - eCAP Input Selection from INPUTXBAR

Best Regards,

Zackary Fleenor

Hi Jayakeerthana,

The tables you have shown in your previous response are all related to the OUTPUTXBAR which is a completely different entity/mux than the INPUTXBAR.

Please review all of section 7.5.11 (X-Bar) for clarity on the difference.

This information isn't mentioned in the datasheet, as any GPIO can be used as an input signal to the INPUTXBAR, and then any INPUTXBAR output signal can be configured as the input the ECAP.

This is shown in the TRM diagram at the following link (https://www.ti.com/lit/ug/spruj55d/spruj55d.pdf#page=917)

Apologies as I am currently unable to insert screenshots into the response. Please review the diagram in the link above for reference.

Best Regards,

Zackary Fleenor