Features Supported

Interrupt mode operation
DMA mode operation
Internal Loopback
Transmit and Receive in TDM format with multi-serializer, multi-slot support.
SysConfig support for driver parameter configuration and initialization.

SysConfig Features

Attention: The instances for McASP needs to be selected the same for serializers for the instance. Syscfg will automatically assign different instances for all and user will be required to assign same instance and choose to ignore the warning.

Note: It is strongly recommend to use SysConfig where it is available instead of using direct SW API calls. This will help simplify the SW application and also catch common mistakes early in the development cycle.

Features NOT Supported

Transmit in DIT mode
Burst Mode
Different audio buffer format for application

Usage Overview

Key Careabouts in Driver Usage

Note: The changes pulled in for the driver starting release 10.0 requires some changes in the Driver usage from application

All transactions submitted from the applications must be of the same size.
- The TX and RX can be of seperate size.
The Loopjob buffer size can be configured from the sysconfig.
Application can provide an external buffer for loopjob buffer from Sysconfig
- This enables application to provide the transaction buffer itself as loopjob
MCASP_stopTransferRx() and MCASP_stopTransferTx() are blocking calls that should not be called from an ISR context.

API Sequence

To use the MCASP driver to send data over the MCASP interface, the application calls the following APIs:

MCASP_init(): Initialize the MCASP driver.
MCASP_open(): Open an instance of the MCASP driver
MCASP_submitRx(): Submit buffers to MCASP driver for reception
MCASP_submitTx(): Submit buffers to MCASP driver for transmission
MCASP_startTransferRx(): Start MCASP receive.
MCASP_startTransferTx(): Start MCASP transmit.
MCASP_stopTransferRx(): Stop MCASP receive.
MCASP_stopTransferTx(): Stop MCASP transmit.
MCASP_withdrawRx(): withdraw buffers submitted to driver for reception
MCASP_withdrawTx(): withdraw buffers submitted to driver for transmission
MCASP_close(): De-initialize the MCASP instance.
MCASP_deinit(): De-Initialize the MCASP driver.

Loopjob Configuration

Mcasp driver allows loopjob enabled/disabled configuration to handle delayed application buffer submission at run time. Loopjob is a default buffer that gets transmitted / received into if the application fails to submit the buffers in time. When loopjob is disabled the last 2 application buffers will be re programmed and re used. The application callback corresponding to the re programmed buffers is not called.

Loopjob buffer is programmed in sys config. Sys config will define a uint8_t array and initialize it to 0.
Application can access the buffer and optionally initialize the data.
If the loopjob buffer is programmed, after sending the full loopjob buffer next submitted buffer is programmed.

Buffer Queuing

The application buffers need to be programmed before starting the transfer.
If the loopjob is enabled application can start without queuing any buffers, Driver will work with the loopjob buffers till application queues the actual buffers.
If loopjob is disabled at least 2 buffers should be queued before starting the mcasp transfer. New buffer will be programmed in the interrupt callback corresponding to current transfer. the application is expected to submit the new buffer before that else the same buffer is re programmed, so it is recommended to start the transfer with at least 3 buffers queued.

Example Usage

Include the below file to access the APIs

#include <drivers/mcasp.h>

Instance Open Example

    MCASP_OpenParams     mcaspParams;
    MCASP_openParamsInit(&mcaspParams); /* Initialize mcasp parameters */
    mcaspParams.edmaInst  = 0;
    mcaspParams.edmaInst     = CONFIG_EDMA0,
    mcaspParams.transferMode = MCASP_TRANSFER_MODE_DMA,
    mcaspParams.txCallbackFxn = mcasp_loopback_txcb,
    mcaspParams.rxCallbackFxn = mcasp_loopback_rxcb,
 
    gMcaspHandle = MCASP_open(CONFIG_MCASP0, &mcaspParams);
    DebugP_assert(gMcaspHandle != NULL);

Instance Close Example

MCASP_close(gMcaspHandle);

Start McASP Transfer Example

    MCASP_Transaction   txnTx[APP_MCASP_MSG_COUNT] = {0};
    MCASP_Transaction   txnRx[APP_MCASP_MSG_COUNT] = {0};
    uint8_t mcaspTxBuffer[APP_MCASP_MSG_COUNT][APP_MCASP_MSGSIZE];
    uint8_t mcaspRxBuffer[APP_MCASP_MSG_COUNT][APP_MCASP_MSGSIZE];
    uint32_t i;
 
    for (i = 0U; i < APP_MCASP_MSG_COUNT; i++)
    {
        txnTx[i].buf = (void*) &mcaspTxBuffer[i][0];
        txnTx[i].count = APP_MCASP_MSGSIZE/4;
        txnTx[i].timeout = 0xFFFFFF;
        MCASP_submitTx(gMcaspHandle, &txnTx[i]);
    }
    for (i = 0U; i < APP_MCASP_MSG_COUNT; i++)
    {
        txnRx[i].buf = (void*) &mcaspRxBuffer[i][0];
        txnRx[i].count = APP_MCASP_MSGSIZE/4;
        txnRx[i].timeout = 0xFFFFFF;
        MCASP_submitRx(gMcaspHandle,  &txnRx[i]);
    }
 
    MCASP_startTransferRx(gMcaspHandle);
    MCASP_startTransferTx(gMcaspHandle);

Stop McASP Transfer Example

    MCASP_stopTransferTx(gMcaspHandle);
    MCASP_stopTransferRx(gMcaspHandle);
 
    /* withdraw the buffers submitted to driver. */
    {
        MCASP_Transaction *transaction;
        do {
            transaction = MCASP_withdrawRx(gMcaspHandle);
        }while (transaction != NULL);
        do {
            transaction = MCASP_withdrawTx(gMcaspHandle);
        }while (transaction != NULL);
    }

SysConfig migration guide 11.01 to 11.02

Note: This section highlights key features that have changed or got added from 11.01 to 11.02 SDK

AUX clock selection

This version of SDK (11.02) gives the configurability to choose between different sources of AUXCLK

MCASP AUX Clock selection

The specific option for AUXCLK will vary from device to device. View long description in Syscfg view for more details on the AUXCLK options to select from.
The frequency for the configurable AUX clock options can be choosen at a global level as this will be applicable across all instances of MCASP.

MCASP AUX Clock Frequency Configuration

Some option in the AUX clock selections might expect the aux clock to be supplied externally to the SoC. Refer the TRM of the specific device to check if the clock is supplied externally or generated interally.
When using an internally generated auxiliary clock source, not all frequency values are achievable due to hardware limitations. If the user-specified frequency cannot be generated, the system will throw a runtime error.

Clock Divider Configurability

This version of SDK (11.02) gives configurability of the High Clock Divider (HCLK Divider), and the BCLK divider.

MCASP Clock Divider Configuration

The "Re-Calculate" button can be used to calculate the divider values that would result in the closest FSYNC value required.
The "Apply" button needs to be pressed to view the frequencies for any change in the Sysconfig GUI that have resulted in a change of frequencies.
Press the "Apply" button to update the frequency information displayed in the Syscfg GUI for all configuration parameters that affect frequency settings.
User have to ensure all the frequencies that is displayed is as expected in the system after pressing "Apply".
User can adjust the Divider values and press the "Apply" button to achieve any specific clock frequencies.

API

APIs for MCASP

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