/* Set block length (in bytes) for read and write.  */
int card_set_blklen(uint32_t instance, int len)
/* Set block length (in bytes) for read and write.  */
int card_set_blklen(uint32_t instance, int len)
{
    command_t cmd;
    int status = FAIL;
    card_cmd_config(&cmd, CMD16, len, READ, RESPONSE_48, DATA_PRESENT_NONE, TRUE, TRUE);
    usdhc_printf("Send CMD16.\n");
    if (host_send_cmd(instance, &cmd) == SUCCESS) {
        status = SUCCESS;
    } 
    return status;
}