SDHC Peripheral Driver

The section describes the programming interface of the SDCH Peripheral driver. More...

SDHC PD FUNCTION
sdhc_status_t	sdhc_init (uint8_t instance, sdhc_host_t *host, const sdhc_user_config_t *config)
	Initializes the Host controller by a specific instance index. More...
void	sdhc_shutdown (sdhc_host_t *host)
	Destroy host controller. More...
sdhc_status_t	sdhc_check_card (sdhc_host_t *host, sdhc_card_t *card)
	check whether the card is present on specified host controller. More...
sdhc_status_t	sdhc_check_ro (sdhc_host_t *host)
	Checks the read only for the attached card. More...
sdhc_status_t	sdhc_config_host (sdhc_host_t *host, sdhc_host_config_t *config)
	Configures the specified host controller. More...
sdhc_status_t	sdhc_issue_request (sdhc_host_t *host, sdhc_request_t *req)
	Issues the request on a specific Host controller and returns on completion. More...

SDHC Peripheral Driver

Overview

The SDHC driver configures the secure digital host controller and provides an easy way to operate the SDHC module.

Initialization

To initialize the SDHC module, call the sdhc_init() function and pass in the configuration data structure.
This is an example code to initialize and configure the driver:

// Define device configuration.
sdhc_init_config_t config = {0};

config.busWidth = SD_BUS_WIDTH_1BIT;
config.clock = 0;

// Initialize
if (sdhc_init(instance, &host, &config) != kStatus_SDHC_NoError)
{
    /* error occurs */
}
else
{
    /* SDHC has been successfully initialized */
}

Issuing a request to the card

The SDHC driver provides a simple way to send commands to and retrieve response/data from the card.This is a example to send the SD_SWITCH command to the card.

sdhc_request_t req = {0};
sdhc_command_t cmd = {0};
sdhc_data_t data = {0};

cmd.index = kSdSwitch;                                  /*  Set command index */
cmd.argument = mode << 31 | 0x00FFFFFF;                 /*  Set argument */
cmd.argument &= ~((0xF) << (group * 4));
cmd.argument |= value << (group * 4);
cmd.flags = SDMMC_RSP_R1 | SDMMC_CMD_ADTC;              /*  Set command flags */

data.blockSize = 64;                                    /*  Set data block size */
data.blockCount = 1;                                    /*  Set data block count */
data.flags = SDMMC_DATA_READ;                           /*  Set data direction */
data.buffer = response;                                 /*  Set data buffer */

/* link data, command with request */
data.req = &req;
data.cmd = &cmd;
req.cmd = &cmd;
req.data = &data;
cmd.data = &data;
if (kStatus_SDHC_NoError != sdhc_issue_request(host, &req))  /* issue reqeust */
{
    /* error occurs */
}
else
{
    /* request has been issued successfully */
}

Function Documentation

sdhc_status_t sdhc_init	(	uint8_t	instance,
		sdhc_host_t *	host,
		const sdhc_user_config_t *	config
	)

This function initializes the SDHC module according to the given initialization configuration structure including the clock frequency, bus width, and card detect callback.

Parameters

instance	the specific instance index
host	the memory address allocated for the host handle
config	initialization configuration data

Returns

kStatus_SDHC_NoError if success

void sdhc_shutdown

(

sdhc_host_t *

host

)

Parameters

host	the pointer to the host controller about to be destroyed

sdhc_status_t sdhc_check_card	(	sdhc_host_t *	host,
		sdhc_card_t *	card
	)

This function checks if there's a card inserted to the SDHC.

Parameters

host	the pointer to the host controller
card	the pointer to retrieve card information

Returns

kStatus_SDHC_NoError on success

sdhc_status_t sdhc_check_ro

(

sdhc_host_t *

host

)

Parameters

host	the pointer to the host controller

Returns

kStatus_SDHC_NoError on success

sdhc_status_t sdhc_config_host	(	sdhc_host_t *	host,
		sdhc_host_config_t *	config
	)

With this function, a user can modify the specific SDHC configuration.

Parameters

host	the pointer to the host controller
config	the pointer to the configuration information

Returns

kStatus_SDHC_NoError on success

sdhc_status_t sdhc_issue_request	(	sdhc_host_t *	host,
		sdhc_request_t *	req
	)

This function issues the request to the card on a specific SDHC. The command is sent and is blocked as long as the response/data is sending back from the card.

Parameters

host	the pointer to the host controller
req	the pointer to the request

Returns

kStatus_SDHC_NoError on success