5.11. GPMC¶

5.11.1.1. Modes of Operation¶

Following modes of operations are supported:

GPMC_OPER_MODE_BLOCKING GPMC_transfer() API blocks code execution until transaction has completed. By default, GPMC driver operates in blocking mode. This ensures only one GPMC transaction operates at a given time. This mode is supported only in interrupt configurations.

GPMC_OPER_MODE_POLLING GPMC_transfer() API blocks code execution until transaction has completed. By default, GPMC driver operates in blocking mode. This ensures only one GPMC transaction operates at a given time. This mode is supported only in non-interrupt configurations.

GPMC_OPER_MODE_CALLBACK GPMC_transfer() API returns without waiting for completion of transaction in this case. Callback function registered by application is invoked once transaction is complete.This mode is supported only in interrupt configuration.

5.11.2.1. Board Specific Configuration¶

All board specific configurations eg:enabling clock and pin-mux for GPMC pins are required before calling any driver APIs.By default Board_init() API supports all initialization sequence for TI supported EVMs. In addition it initializes UART instance for Console/STDIO.Refer PDK Board Support for additional details.Once board specific configuration is complete GPMC_init() API should be called to initialize driver.

5.11.2.2. SoC Specific Configuration¶

All SoC specific configurations (eg: GPMC module registers base address, interrupt configurations, etc.) can be set using GPMC_socSetInitCfg() SoC driver API before calling any GPMC driver APIs. The default SoC specific configurations can be retrieved using GPMC_socGetInitCfg() SoC driver API.

5.11.2.3. GPMC Configuration Structure¶

The GPMC_soc.c file binds driver with hardware attributes on the board through GPMC_config[] structure. This structure must be provided to the GPMC driver. It must be initialized before the GPMC_init() function is called and cannot be changed afterwards.

For details about individual fields of this library structure, see the PDK doxygen documentation

5.11.3.1. Open GPMC¶

...
Board_init(boardCfg);
...
GPMC_socGetInitCfg(peripheralNum, &spi_cfg);
...
GPMC_socSetInitCfg(peripheralNum, &gpmc_cfg);
GPMC_Params_init(&spiParams);
spiParams.transferMode = GPMC_OPER_MODE_BLOCKING;
spiParams.transferCallbackFxn = NULL;
handle = GPMC_open(peripheralNum, &params);

At this point GPMC driver is ready for data transfer in blocking mode on specific instance identified by handle. Pseudo/Sample code for GPMC read/write transaction is included below. Refer example for additional details

...
transaction.count = n;    /* Transfer Length */
transaction.txBuf = transmitBuffer; /* Buffer to be written */
transaction.rxBuf = NULL;  /* Buffer holding the received data */
transferOK = GPMC_transfer(handle, transaction); /* Perform GPMC transfer */
if (!transferOK) {
/* GPMC transaction failed */
}

5.11.4.1. GPMC¶