}
+
+/* Write one block of data.
+ * Return -ENODEV on error, -EBUSY on timeout, or CRC on success
+ */
+int sdmmc_write_block(const struct sdmmc_card* mmc, uint32_t block_number, uint8_t* buffer)
+{
+ uint16_t crc = 0xFFFF;
+ int ret = 0;
+
+ if ((buffer == NULL) || (mmc->card_type == MMC_CARDTYPE_UNKNOWN)) {
+ return -EINVAL;
+ }
+
+ if (mmc->card_type != MMC_CARDTYPE_SDV2_HC) {
+ block_number = (block_number << mmc->block_shift);
+ }
+
+ /* Get SPI Bus */
+ spi_get_mutex(mmc->ssp_bus_num);
+ sdmmc_cs_activate(mmc);
+
+ /* Erase blocks */
+ /* FIXME */
+
+ ret = sdmmc_send_command(mmc, MMC_WRITE_SINGLE_BLOCK, block_number, NULL, 0);
+ if (ret != MMC_R1_NO_ERROR) {
+ ret = -ENODEV;
+ goto read_release;
+ }
+
+ /* Wait for start of Data */
+ ret = sdmmc_wait_for_ready(mmc, MMC_START_DATA_BLOCK_TOCKEN);
+ if (ret != MMC_START_DATA_BLOCK_TOCKEN) {
+ ret = -EBUSY;
+ goto read_release;
+ }
+
+ /* Read data */
+ spi_transfer_multiple_frames(mmc->ssp_bus_num, NULL, buffer, mmc->block_size, 8);
+ /* Read CRC */
+ spi_transfer_multiple_frames(mmc->ssp_bus_num, NULL, (uint8_t*)(&crc), 2, 8);
+
+ ret = crc;
+
+read_release:
+ /* Release SPI Bus */
+ sdmmc_cs_release(mmc);
+ spi_release_mutex(mmc->ssp_bus_num);
+ return ret;
+}
+
+
+
