diff --git a/src/W800_SDK_v1.00.10/app/app_drivers/mmc_sdio/mmc_sdio.c b/src/W800_SDK_v1.00.10/app/app_drivers/mmc_sdio/mmc_sdio.c
index 0dbe660..dacdb22 100644
--- a/src/W800_SDK_v1.00.10/app/app_drivers/mmc_sdio/mmc_sdio.c
+++ b/src/W800_SDK_v1.00.10/app/app_drivers/mmc_sdio/mmc_sdio.c
@@ -99,7 +99,7 @@ void mmc_sdio_driver_write_dma_async(uint32_t *data, uint32_t dataLengthInBytes)
 void mmc_sdio_driver_write_one(uint8_t data)
 {
     /* Wait for MMC device to be ready to send the data */
-    while (SDIO_HOST->MMC_IO & 0x01);
+    mmc_sdio_driver_blocking_wait_bus_free();
     
     SDIO_HOST->BUF_CTL = 0x4820;
     SDIO_HOST->DATA_BUF[0] = (uint32_t)data;
@@ -107,19 +107,25 @@ void mmc_sdio_driver_write_one(uint8_t data)
     /* Start the transfer */
     SDIO_HOST->MMC_IO = 0x01;
     /* Wait for MMC device to be done sending the data */
-    while (SDIO_HOST->MMC_IO & 0x01);
+    mmc_sdio_driver_blocking_wait_bus_free();
 }
 
 void mmc_sdio_driver_write(const uint8_t *data, uint16_t dataLengthInBytes)
 {
     /* Wait for MMC device to be ready to send the data */
-    while (SDIO_HOST->MMC_IO & 0x01);
+    mmc_sdio_driver_blocking_wait_bus_free();
 
     SDIO_HOST->BUF_CTL = 0x4820;
     memcpy((void *)SDIO_HOST->DATA_BUF, (void *)data, dataLengthInBytes);
     SDIO_HOST->MMC_BYTECNTL = dataLengthInBytes;
     /* Start the transfer */
     SDIO_HOST->MMC_IO = 0x01;
+
     /* Wait for MMC device to be done sending the data */
+    mmc_sdio_driver_blocking_wait_bus_free();
+}
+
+void mmc_sdio_driver_blocking_wait_bus_free(void)
+{
     while (SDIO_HOST->MMC_IO & 0x01);
 }
diff --git a/src/W800_SDK_v1.00.10/app/app_drivers/mmc_sdio/mmc_sdio.h b/src/W800_SDK_v1.00.10/app/app_drivers/mmc_sdio/mmc_sdio.h
index 2a1ec8d..f20e4a0 100644
--- a/src/W800_SDK_v1.00.10/app/app_drivers/mmc_sdio/mmc_sdio.h
+++ b/src/W800_SDK_v1.00.10/app/app_drivers/mmc_sdio/mmc_sdio.h
@@ -23,7 +23,7 @@ void mmc_sdio_driver_periph_init(DMATransferDoneCb_t DMATransferDoneCb, void *ar
  * @param dataLengthInBytes the size in bytes of the data to transfer.
  * Maximum length is 65535 bytes.
  */
-void mmc_sdio_driver_write_dma_async(uint32_t *data, u32 dataLengthInBytes);
+void mmc_sdio_driver_write_dma_async(uint32_t *data, uint32_t dataLengthInBytes);
 
 /**
  * @brief Sends one byte of data to the slave
@@ -43,4 +43,10 @@ void mmc_sdio_driver_write_one(uint8_t data);
  */
 void mmc_sdio_driver_write(const uint8_t *data, uint16_t dataLengthInBytes);
 
+/**
+ * @brief Performs a busy wait until the data bus is free for us to use.
+ * 
+ */
+void mmc_sdio_driver_blocking_wait_bus_free(void);
+
 #endif //MMC_SDIO_H
\ No newline at end of file