🎨 Format onboard_sd.cpp

Marlin/src/HAL/STM32F1/onboard_sd.cpp

@@ -38,8 +38,8 @@
   #define SPI_CLOCK_MAX SPI_BAUD_PCLK_DIV_2
 #endif
 
-#define CS_LOW()  WRITE(ONBOARD_SD_CS_PIN, LOW)  /* Set OnboardSPI cs low */
-#define CS_HIGH() WRITE(ONBOARD_SD_CS_PIN, HIGH) /* Set OnboardSPI cs high */
+#define CS_LOW()  WRITE(ONBOARD_SD_CS_PIN, LOW)  // Set OnboardSPI cs low
+#define CS_HIGH() WRITE(ONBOARD_SD_CS_PIN, HIGH) // Set OnboardSPI cs high
 
 #define FCLK_FAST() ONBOARD_SD_SPI.setClockDivider(SPI_CLOCK_MAX)
 #define FCLK_SLOW() ONBOARD_SD_SPI.setClockDivider(SPI_BAUD_PCLK_DIV_256)
@@ -49,32 +49,32 @@
 ---------------------------------------------------------------------------*/
 
 /* MMC/SD command */
-#define CMD0  (0)     /* GO_IDLE_STATE */
-#define CMD1  (1)     /* SEND_OP_COND (MMC) */
-#define ACMD41  (0x80+41) /* SEND_OP_COND (SDC) */
-#define CMD8  (8)     /* SEND_IF_COND */
-#define CMD9  (9)     /* SEND_CSD */
-#define CMD10 (10)    /* SEND_CID */
-#define CMD12 (12)    /* STOP_TRANSMISSION */
-#define ACMD13  (0x80+13) /* SD_STATUS (SDC) */
-#define CMD16 (16)    /* SET_BLOCKLEN */
-#define CMD17 (17)    /* READ_SINGLE_BLOCK */
-#define CMD18 (18)    /* READ_MULTIPLE_BLOCK */
-#define CMD23 (23)    /* SET_BLOCK_COUNT (MMC) */
-#define ACMD23  (0x80+23) /* SET_WR_BLK_ERASE_COUNT (SDC) */
-#define CMD24 (24)    /* WRITE_BLOCK */
-#define CMD25 (25)    /* WRITE_MULTIPLE_BLOCK */
-#define CMD32 (32)    /* ERASE_ER_BLK_START */
-#define CMD33 (33)    /* ERASE_ER_BLK_END */
-#define CMD38 (38)    /* ERASE */
-#define CMD48 (48)    /* READ_EXTR_SINGLE */
-#define CMD49 (49)    /* WRITE_EXTR_SINGLE */
-#define CMD55 (55)    /* APP_CMD */
-#define CMD58 (58)    /* READ_OCR */
-
-static volatile DSTATUS Stat = STA_NOINIT;  /* Physical drive status */
+#define CMD0  (0)         // GO_IDLE_STATE
+#define CMD1  (1)         // SEND_OP_COND (MMC)
+#define ACMD41  (0x80+41) // SEND_OP_COND (SDC)
+#define CMD8  (8)         // SEND_IF_COND
+#define CMD9  (9)         // SEND_CSD
+#define CMD10 (10)        // SEND_CID
+#define CMD12 (12)        // STOP_TRANSMISSION
+#define ACMD13  (0x80+13) // SD_STATUS (SDC)
+#define CMD16 (16)        // SET_BLOCKLEN
+#define CMD17 (17)        // READ_SINGLE_BLOCK
+#define CMD18 (18)        // READ_MULTIPLE_BLOCK
+#define CMD23 (23)        // SET_BLOCK_COUNT (MMC)
+#define ACMD23  (0x80+23) // SET_WR_BLK_ERASE_COUNT (SDC)
+#define CMD24 (24)        // WRITE_BLOCK
+#define CMD25 (25)        // WRITE_MULTIPLE_BLOCK
+#define CMD32 (32)        // ERASE_ER_BLK_START
+#define CMD33 (33)        // ERASE_ER_BLK_END
+#define CMD38 (38)        // ERASE
+#define CMD48 (48)        // READ_EXTR_SINGLE
+#define CMD49 (49)        // WRITE_EXTR_SINGLE
+#define CMD55 (55)        // APP_CMD
+#define CMD58 (58)        // READ_OCR
+
+static volatile DSTATUS Stat = STA_NOINIT;  // Physical drive status
 static volatile UINT timeout;
-static BYTE CardType;      /* Card type flags */
+static BYTE CardType;                       // Card type flags
 
 /*-----------------------------------------------------------------------*/
 /* Send/Receive data to the MMC  (Platform dependent)                    */
@@ -82,7 +82,7 @@ static BYTE CardType;      /* Card type flags */
 
 /* Exchange a byte */
 static BYTE xchg_spi (
-  BYTE dat  /* Data to send */
+  BYTE dat  // Data to send
 ) {
   BYTE returnByte = ONBOARD_SD_SPI.transfer(dat);
   return returnByte;
@@ -90,18 +90,18 @@ static BYTE xchg_spi (
 
 /* Receive multiple byte */
 static void rcvr_spi_multi (
-  BYTE *buff,   /* Pointer to data buffer */
-  UINT btr    /* Number of bytes to receive (16, 64 or 512) */
+  BYTE *buff,   // Pointer to data buffer
+  UINT btr      // Number of bytes to receive (16, 64 or 512)
 ) {
   ONBOARD_SD_SPI.dmaTransfer(0, const_cast<uint8_t*>(buff), btr);
 }
 
 #if _DISKIO_WRITE
 
-  /* Send multiple bytes */
+  // Send multiple bytes
   static void xmit_spi_multi (
-    const BYTE *buff, /* Pointer to the data */
-    UINT btx      /* Number of bytes to send (multiple of 16) */
+    const BYTE *buff, // Pointer to the data
+    UINT btx          // Number of bytes to send (multiple of 16)
   ) {
     ONBOARD_SD_SPI.dmaSend(const_cast<uint8_t*>(buff), btx);
   }
@@ -112,16 +112,15 @@ static void rcvr_spi_multi (
 /* Wait for card ready                                                   */
 /*-----------------------------------------------------------------------*/
 
-static int wait_ready (  /* 1:Ready, 0:Timeout */
-  UINT wt     /* Timeout [ms] */
+static int wait_ready ( // 1:Ready, 0:Timeout
+  UINT wt               // Timeout [ms]
 ) {
   BYTE d;
-
   timeout = millis() + wt;
   do {
     d = xchg_spi(0xFF);
-    /* This loop takes a while. Insert rot_rdq() here for multitask environment. */
-  } while (d != 0xFF && (timeout > millis()));  /* Wait for card goes ready or timeout */
+    // This loop takes a while. Insert rot_rdq() here for multitask environment.
+  } while (d != 0xFF && (timeout > millis()));  // Wait for card goes ready or timeout
 
   return (d == 0xFF) ? 1 : 0;
 }
@@ -131,21 +130,21 @@ static int wait_ready (  /* 1:Ready, 0:Timeout */
 /*-----------------------------------------------------------------------*/
 
 static void deselect() {
-  CS_HIGH();    /* CS = H */
-  xchg_spi(0xFF); /* Dummy clock (force DO hi-z for multiple slave SPI) */
+  CS_HIGH();      // CS = H
+  xchg_spi(0xFF); // Dummy clock (force DO hi-z for multiple slave SPI)
 }
 
 /*-----------------------------------------------------------------------*/
 /* Select card and wait for ready                                        */
 /*-----------------------------------------------------------------------*/
 
-static int select() { /* 1:OK, 0:Timeout */
-  CS_LOW();   /* CS = L */
-  xchg_spi(0xFF); /* Dummy clock (force DO enabled) */
+static int select() {             // 1:OK, 0:Timeout
+  CS_LOW();                       // CS = L
+  xchg_spi(0xFF);                 // Dummy clock (force DO enabled)
 
-  if (wait_ready(500)) return 1;  /* Leading busy check: Wait for card ready */
+  if (wait_ready(500)) return 1;  // Leading busy check: Wait for card ready
 
-  deselect();   /* Timeout */
+  deselect();                     // Timeout
   return 0;
 }
 
@@ -153,16 +152,18 @@ static int select() { /* 1:OK, 0:Timeout */
 /* Control SPI module (Platform dependent)                               */
 /*-----------------------------------------------------------------------*/
 
-static void power_on() {  /* Enable SSP module and attach it to I/O pads */
+// Enable SSP module and attach it to I/O pads
+static void sd_power_on() {
   ONBOARD_SD_SPI.setModule(ONBOARD_SPI_DEVICE);
   ONBOARD_SD_SPI.begin();
   ONBOARD_SD_SPI.setBitOrder(MSBFIRST);
   ONBOARD_SD_SPI.setDataMode(SPI_MODE0);
-  OUT_WRITE(ONBOARD_SD_CS_PIN, HIGH); /* Set CS# high */
+  OUT_WRITE(ONBOARD_SD_CS_PIN, HIGH); // Set CS# high
 }
 
-static void power_off() {   /* Disable SPI function */
-  select();       /* Wait for card ready */
+// Disable SPI function
+static void sd_power_off() {
+  select();                           // Wait for card ready
   deselect();
 }
 
@@ -170,23 +171,23 @@ static void power_off() {   /* Disable SPI function */
 /* Receive a data packet from the MMC                                    */
 /*-----------------------------------------------------------------------*/
 
-static int rcvr_datablock (  /* 1:OK, 0:Error */
-  BYTE *buff,     /* Data buffer */
-  UINT btr      /* Data block length (byte) */
+static int rcvr_datablock (   // 1:OK, 0:Error
+  BYTE *buff,                 // Data buffer
+  UINT btr                    // Data block length (byte)
 ) {
   BYTE token;
 
   timeout = millis() + 200;
-  do {              /* Wait for DataStart token in timeout of 200ms */
+  do {                            // Wait for DataStart token in timeout of 200ms
     token = xchg_spi(0xFF);
-    /* This loop will take a while. Insert rot_rdq() here for multitask environment. */
+                                  // This loop will take a while. Insert rot_rdq() here for multitask environment.
   } while ((token == 0xFF) && (timeout > millis()));
-  if (token != 0xFE) return 0;   /* Function fails if invalid DataStart token or timeout */
+  if (token != 0xFE) return 0;    // Function fails if invalid DataStart token or timeout
 
-  rcvr_spi_multi(buff, btr);    /* Store trailing data to the buffer */
-  xchg_spi(0xFF); xchg_spi(0xFF); /* Discard CRC */
+  rcvr_spi_multi(buff, btr);      // Store trailing data to the buffer
+  xchg_spi(0xFF); xchg_spi(0xFF); // Discard CRC
 
-  return 1;           /* Function succeeded */
+  return 1;                       // Function succeeded
 }
 
 /*-----------------------------------------------------------------------*/
@@ -195,25 +196,25 @@ static int rcvr_datablock (  /* 1:OK, 0:Error */
 
 #if _DISKIO_WRITE
 
-  static int xmit_datablock (  /* 1:OK, 0:Failed */
-    const BYTE *buff, /* Ponter to 512 byte data to be sent */
-    BYTE token      /* Token */
+  static int xmit_datablock(  // 1:OK, 0:Failed
+    const BYTE *buff,         // Pointer to 512 byte data to be sent
+    BYTE token                // Token
   ) {
     BYTE resp;
 
-    if (!wait_ready(500)) return 0;   /* Leading busy check: Wait for card ready to accept data block */
+    if (!wait_ready(500)) return 0;       // Leading busy check: Wait for card ready to accept data block
 
-    xchg_spi(token);          /* Send token */
-    if (token == 0xFD) return 1;    /* Do not send data if token is StopTran */
+    xchg_spi(token);                      // Send token
+    if (token == 0xFD) return 1;          // Do not send data if token is StopTran
 
-    xmit_spi_multi(buff, 512);      /* Data */
-    xchg_spi(0xFF); xchg_spi(0xFF);   /* Dummy CRC */
+    xmit_spi_multi(buff, 512);            // Data
+    xchg_spi(0xFF); xchg_spi(0xFF);       // Dummy CRC
 
-    resp = xchg_spi(0xFF);        /* Receive data resp */
+    resp = xchg_spi(0xFF);                // Receive data resp
 
-    return (resp & 0x1F) == 0x05 ? 1 : 0; /* Data was accepted or not */
+    return (resp & 0x1F) == 0x05 ? 1 : 0; // Data was accepted or not
 
-    /* Busy check is done at next transmission */
+    // Busy check is done at next transmission
   }
 
 #endif // _DISKIO_WRITE
@@ -222,43 +223,43 @@ static int rcvr_datablock (  /* 1:OK, 0:Error */
 /* Send a command packet to the MMC                                      */
 /*-----------------------------------------------------------------------*/
 
-static BYTE send_cmd (   /* Return value: R1 resp (bit7==1:Failed to send) */
-  BYTE cmd,   /* Command index */
-  DWORD arg   /* Argument */
+static BYTE send_cmd( // Return value: R1 resp (bit7==1:Failed to send)
+  BYTE cmd,           // Command index
+  DWORD arg           // Argument
 ) {
   BYTE n, res;
 
-  if (cmd & 0x80) { /* Send a CMD55 prior to ACMD<n> */
+  if (cmd & 0x80) {   // Send a CMD55 prior to ACMD<n>
     cmd &= 0x7F;
     res = send_cmd(CMD55, 0);
     if (res > 1) return res;
   }
 
-  /* Select the card and wait for ready except to stop multiple block read */
+  // Select the card and wait for ready except to stop multiple block read
   if (cmd != CMD12) {
     deselect();
     if (!select()) return 0xFF;
   }
 
-  /* Send command packet */
-  xchg_spi(0x40 | cmd);       /* Start + command index */
-  xchg_spi((BYTE)(arg >> 24));    /* Argument[31..24] */
-  xchg_spi((BYTE)(arg >> 16));    /* Argument[23..16] */
-  xchg_spi((BYTE)(arg >> 8));     /* Argument[15..8] */
-  xchg_spi((BYTE)arg);        /* Argument[7..0] */
-  n = 0x01;             /* Dummy CRC + Stop */
-  if (cmd == CMD0) n = 0x95;      /* Valid CRC for CMD0(0) */
-  if (cmd == CMD8) n = 0x87;      /* Valid CRC for CMD8(0x1AA) */
+  // Send command packet
+  xchg_spi(0x40 | cmd);         // Start + command index
+  xchg_spi((BYTE)(arg >> 24));  // Argument[31..24]
+  xchg_spi((BYTE)(arg >> 16));  // Argument[23..16]
+  xchg_spi((BYTE)(arg >> 8));   // Argument[15..8]
+  xchg_spi((BYTE)arg);          // Argument[7..0]
+  n = 0x01;                     // Dummy CRC + Stop
+  if (cmd == CMD0) n = 0x95;    // Valid CRC for CMD0(0)
+  if (cmd == CMD8) n = 0x87;    // Valid CRC for CMD8(0x1AA)
   xchg_spi(n);
 
-  /* Receive command resp */
-  if (cmd == CMD12) xchg_spi(0xFF); /* Diacard following one byte when CMD12 */
-  n = 10;               /* Wait for response (10 bytes max) */
+  // Receive command response
+  if (cmd == CMD12) xchg_spi(0xFF); // Discard the following byte when CMD12
+  n = 10;                           // Wait for response (10 bytes max)
   do
     res = xchg_spi(0xFF);
   while ((res & 0x80) && --n);
 
-  return res;             /* Return received response */
+  return res;                   // Return received response
 }
 
 /*--------------------------------------------------------------------------
@@ -270,49 +271,52 @@ static BYTE send_cmd (   /* Return value: R1 resp (bit7==1:Failed to send) */
 /*-----------------------------------------------------------------------*/
 
 DSTATUS disk_initialize (
-  BYTE drv    /* Physical drive number (0) */
+  BYTE drv                                                            // Physical drive number (0)
 ) {
   BYTE n, cmd, ty, ocr[4];
 
-  if (drv) return STA_NOINIT;     /* Supports only drive 0 */
-  power_on();             /* Initialize SPI */
+  if (drv) return STA_NOINIT;                                         // Supports only drive 0
+  sd_power_on();                                                      // Initialize SPI
 
-  if (Stat & STA_NODISK) return Stat; /* Is a card existing in the soket? */
+  if (Stat & STA_NODISK) return Stat;                                 // Is a card existing in the soket?
 
   FCLK_SLOW();
-  for (n = 10; n; n--) xchg_spi(0xFF);  /* Send 80 dummy clocks */
+  for (n = 10; n; n--) xchg_spi(0xFF);                                // Send 80 dummy clocks
 
   ty = 0;
-  if (send_cmd(CMD0, 0) == 1) {     /* Put the card SPI state */
-    timeout = millis() + 1000;            /* Initialization timeout = 1 sec */
-    if (send_cmd(CMD8, 0x1AA) == 1) { /* Is the catd SDv2? */
-      for (n = 0; n < 4; n++) ocr[n] = xchg_spi(0xFF);  /* Get 32 bit return value of R7 resp */
-      if (ocr[2] == 0x01 && ocr[3] == 0xAA) {       /* Does the card support 2.7-3.6V? */
-        while ((timeout > millis()) && send_cmd(ACMD41, 1UL << 30)) ; /* Wait for end of initialization with ACMD41(HCS) */
-        if ((timeout > millis()) && send_cmd(CMD58, 0) == 0) {    /* Check CCS bit in the OCR */
+  if (send_cmd(CMD0, 0) == 1) {                                       // Put the card SPI state
+    timeout = millis() + 1000;                                        // Initialization timeout = 1 sec
+    if (send_cmd(CMD8, 0x1AA) == 1) {                                 // Is the catd SDv2?
+      for (n = 0; n < 4; n++) ocr[n] = xchg_spi(0xFF);                // Get 32 bit return value of R7 resp
+      if (ocr[2] == 0x01 && ocr[3] == 0xAA) {                         // Does the card support 2.7-3.6V?
+        while ((timeout > millis()) && send_cmd(ACMD41, 1UL << 30));  // Wait for end of initialization with ACMD41(HCS)
+        if ((timeout > millis()) && send_cmd(CMD58, 0) == 0) {        // Check CCS bit in the OCR
           for (n = 0; n < 4; n++) ocr[n] = xchg_spi(0xFF);
-          ty = (ocr[0] & 0x40) ? CT_SD2 | CT_BLOCK : CT_SD2;  /* Check if the card is SDv2 */
+          ty = (ocr[0] & 0x40) ? CT_SD2 | CT_BLOCK : CT_SD2;          // Check if the card is SDv2
         }
       }
-    } else {  /* Not an SDv2 card */
-      if (send_cmd(ACMD41, 0) <= 1)   { /* SDv1 or MMCv3? */
-        ty = CT_SD1; cmd = ACMD41;  /* SDv1 (ACMD41(0)) */
-      } else {
-        ty = CT_MMC; cmd = CMD1;  /* MMCv3 (CMD1(0)) */
+    }
+    else {                                                            // Not an SDv2 card
+      if (send_cmd(ACMD41, 0) <= 1)   {                               // SDv1 or MMCv3?
+        ty = CT_SD1; cmd = ACMD41;                                    // SDv1 (ACMD41(0))
+      }
+      else {
+        ty = CT_MMC; cmd = CMD1;                                      // MMCv3 (CMD1(0))
       }
-      while ((timeout > millis()) && send_cmd(cmd, 0)) ;    /* Wait for the card leaves idle state */
-      if (!(timeout > millis()) || send_cmd(CMD16, 512) != 0) /* Set block length: 512 */
+      while ((timeout > millis()) && send_cmd(cmd, 0));               // Wait for the card leaves idle state
+      if (!(timeout > millis()) || send_cmd(CMD16, 512) != 0)         // Set block length: 512
         ty = 0;
     }
   }
-  CardType = ty;  /* Card type */
+  CardType = ty;                                                      // Card type
   deselect();
 
-  if (ty) {   /* OK */
-    FCLK_FAST();      /* Set fast clock */
-    Stat &= ~STA_NOINIT;  /* Clear STA_NOINIT flag */
-  } else {    /* Failed */
-    power_off();
+  if (ty) {                                                           // OK
+    FCLK_FAST();                                                      // Set fast clock
+    Stat &= ~STA_NOINIT;                                              // Clear STA_NOINIT flag
+  }
+  else {                                                              // Failed
+    sd_power_off();
     Stat = STA_NOINIT;
   }
 
@@ -324,10 +328,10 @@ DSTATUS disk_initialize (
 /*-----------------------------------------------------------------------*/
 
 DSTATUS disk_status (
-  BYTE drv    /* Physical drive number (0) */
+  BYTE drv                    // Physical drive number (0)
 ) {
-  if (drv) return STA_NOINIT;   /* Supports only drive 0 */
-  return Stat;  /* Return disk status */
+  if (drv) return STA_NOINIT; // Supports only drive 0
+  return Stat;                // Return disk status
 }
 
 /*-----------------------------------------------------------------------*/
@@ -335,28 +339,28 @@ DSTATUS disk_status (
 /*-----------------------------------------------------------------------*/
 
 DRESULT disk_read (
-  BYTE drv,   /* Physical drive number (0) */
-  BYTE *buff,   /* Pointer to the data buffer to store read data */
-  DWORD sector, /* Start sector number (LBA) */
-  UINT count    /* Number of sectors to read (1..128) */
+  BYTE drv,     // Physical drive number (0)
+  BYTE *buff,   // Pointer to the data buffer to store read data
+  DWORD sector, // Start sector number (LBA)
+  UINT count    // Number of sectors to read (1..128)
 ) {
   BYTE cmd;
 
-  if (drv || !count) return RES_PARERR;   /* Check parameter */
-  if (Stat & STA_NOINIT) return RES_NOTRDY; /* Check if drive is ready */
-  if (!(CardType & CT_BLOCK)) sector *= 512;  /* LBA ot BA conversion (byte addressing cards) */
+  if (drv || !count) return RES_PARERR;       // Check parameter
+  if (Stat & STA_NOINIT) return RES_NOTRDY;   // Check if drive is ready
+  if (!(CardType & CT_BLOCK)) sector *= 512;  // LBA ot BA conversion (byte addressing cards)
   FCLK_FAST();
-  cmd = count > 1 ? CMD18 : CMD17;      /*  READ_MULTIPLE_BLOCK : READ_SINGLE_BLOCK */
+  cmd = count > 1 ? CMD18 : CMD17;            //  READ_MULTIPLE_BLOCK : READ_SINGLE_BLOCK
   if (send_cmd(cmd, sector) == 0) {
     do {
       if (!rcvr_datablock(buff, 512)) break;
       buff += 512;
     } while (--count);
-    if (cmd == CMD18) send_cmd(CMD12, 0); /* STOP_TRANSMISSION */
+    if (cmd == CMD18) send_cmd(CMD12, 0);     // STOP_TRANSMISSION
   }
   deselect();
 
-  return count ? RES_ERROR : RES_OK;  /* Return result */
+  return count ? RES_ERROR : RES_OK;          // Return result
 }
 
 /*-----------------------------------------------------------------------*/
@@ -366,36 +370,36 @@ DRESULT disk_read (
 #if _DISKIO_WRITE
 
   DRESULT disk_write(
-    BYTE drv,     /* Physical drive number (0) */
-    const BYTE *buff, /* Ponter to the data to write */
-    DWORD sector,   /* Start sector number (LBA) */
-    UINT count      /* Number of sectors to write (1..128) */
+    BYTE drv,                                   // Physical drive number (0)
+    const BYTE *buff,                           // Pointer to the data to write
+    DWORD sector,                               // Start sector number (LBA)
+    UINT count                                  // Number of sectors to write (1..128)
   ) {
-    if (drv || !count) return RES_PARERR;   /* Check parameter */
-    if (Stat & STA_NOINIT) return RES_NOTRDY; /* Check drive status */
-    if (Stat & STA_PROTECT) return RES_WRPRT; /* Check write protect */
+    if (drv || !count) return RES_PARERR;       // Check parameter
+    if (Stat & STA_NOINIT) return RES_NOTRDY;   // Check drive status
+    if (Stat & STA_PROTECT) return RES_WRPRT;   // Check write protect
     FCLK_FAST();
-    if (!(CardType & CT_BLOCK)) sector *= 512;  /* LBA ==> BA conversion (byte addressing cards) */
+    if (!(CardType & CT_BLOCK)) sector *= 512;  // LBA ==> BA conversion (byte addressing cards)
 
-    if (count == 1) { /* Single sector write */
-      if ((send_cmd(CMD24, sector) == 0)  /* WRITE_BLOCK */
+    if (count == 1) {                           // Single sector write
+      if ((send_cmd(CMD24, sector) == 0)        // WRITE_BLOCK
         && xmit_datablock(buff, 0xFE)) {
         count = 0;
       }
     }
-    else {        /* Multiple sector write */
-      if (CardType & CT_SDC) send_cmd(ACMD23, count); /* Predefine number of sectors */
-      if (send_cmd(CMD25, sector) == 0) { /* WRITE_MULTIPLE_BLOCK */
+    else {                                            // Multiple sector write
+      if (CardType & CT_SDC) send_cmd(ACMD23, count); // Predefine number of sectors
+      if (send_cmd(CMD25, sector) == 0) {             // WRITE_MULTIPLE_BLOCK
         do {
           if (!xmit_datablock(buff, 0xFC)) break;
           buff += 512;
         } while (--count);
-        if (!xmit_datablock(0, 0xFD)) count = 1;  /* STOP_TRAN token */
+        if (!xmit_datablock(0, 0xFD)) count = 1;      // STOP_TRAN token
       }
     }
     deselect();
 
-    return count ? RES_ERROR : RES_OK;  /* Return result */
+    return count ? RES_ERROR : RES_OK;                // Return result
   }
 
 #endif // _DISKIO_WRITE
@@ -407,9 +411,9 @@ DRESULT disk_read (
 #if _DISKIO_IOCTL
 
   DRESULT disk_ioctl (
-    BYTE drv,   /* Physical drive number (0) */
-    BYTE cmd,   /* Control command code */
-    void *buff    /* Pointer to the conrtol data */
+    BYTE drv,   // Physical drive number (0)
+    BYTE cmd,   // Control command code
+    void *buff  // Pointer to the conrtol data
   ) {
     DRESULT res;
     BYTE n, csd[16], *ptr = (BYTE *)buff;
@@ -420,22 +424,23 @@ DRESULT disk_read (
       UINT dc;
     #endif
 
-    if (drv) return RES_PARERR;         /* Check parameter */
-    if (Stat & STA_NOINIT) return RES_NOTRDY; /* Check if drive is ready */
+    if (drv) return RES_PARERR;                 // Check parameter
+    if (Stat & STA_NOINIT) return RES_NOTRDY;   // Check if drive is ready
 
     res = RES_ERROR;
     FCLK_FAST();
     switch (cmd) {
-      case CTRL_SYNC:     /* Wait for end of internal write process of the drive */
+      case CTRL_SYNC:                           // Wait for end of internal write process of the drive
         if (select()) res = RES_OK;
         break;
 
-      case GET_SECTOR_COUNT:  /* Get drive capacity in unit of sector (DWORD) */
+      case GET_SECTOR_COUNT:                    // Get drive capacity in unit of sector (DWORD)
         if ((send_cmd(CMD9, 0) == 0) && rcvr_datablock(csd, 16)) {
-          if ((csd[0] >> 6) == 1) { /* SDC ver 2.00 */
+          if ((csd[0] >> 6) == 1) {             // SDC ver 2.00
             csize = csd[9] + ((WORD)csd[8] << 8) + ((DWORD)(csd[7] & 63) << 16) + 1;
             *(DWORD*)buff = csize << 10;
-          } else {          /* SDC ver 1.XX or MMC ver 3 */
+          }
+          else {                                // SDC ver 1.XX or MMC ver 3
             n = (csd[5] & 15) + ((csd[10] & 128) >> 7) + ((csd[9] & 3) << 1) + 2;
             csize = (csd[8] >> 6) + ((WORD)csd[7] << 2) + ((WORD)(csd[6] & 3) << 10) + 1;
             *(DWORD*)buff = csize << (n - 9);
@@ -444,21 +449,23 @@ DRESULT disk_read (
         }
         break;
 
-      case GET_BLOCK_SIZE:  /* Get erase block size in unit of sector (DWORD) */
-        if (CardType & CT_SD2) {  /* SDC ver 2.00 */
-          if (send_cmd(ACMD13, 0) == 0) { /* Read SD status */
+      case GET_BLOCK_SIZE:                              // Get erase block size in unit of sector (DWORD)
+        if (CardType & CT_SD2) {                        // SDC ver 2.00
+          if (send_cmd(ACMD13, 0) == 0) {               // Read SD status
             xchg_spi(0xFF);
-            if (rcvr_datablock(csd, 16)) {        /* Read partial block */
-              for (n = 64 - 16; n; n--) xchg_spi(0xFF); /* Purge trailing data */
+            if (rcvr_datablock(csd, 16)) {              // Read partial block
+              for (n = 64 - 16; n; n--) xchg_spi(0xFF); // Purge trailing data
               *(DWORD*)buff = 16UL << (csd[10] >> 4);
               res = RES_OK;
             }
           }
-        } else {          /* SDC ver 1.XX or MMC */
-          if ((send_cmd(CMD9, 0) == 0) && rcvr_datablock(csd, 16)) {  /* Read CSD */
-            if (CardType & CT_SD1) {  /* SDC ver 1.XX */
+        }
+        else {                                                        // SDC ver 1.XX or MMC
+          if ((send_cmd(CMD9, 0) == 0) && rcvr_datablock(csd, 16)) {  // Read CSD
+            if (CardType & CT_SD1) {                                  // SDC ver 1.XX
               *(DWORD*)buff = (((csd[10] & 63) << 1) + ((WORD)(csd[11] & 128) >> 7) + 1) << ((csd[13] >> 6) - 1);
-            } else {          /* MMC */
+            }
+            else {                                                    // MMC
               *(DWORD*)buff = ((WORD)((csd[10] & 124) >> 2) + 1) * (((csd[11] & 3) << 3) + ((csd[11] & 224) >> 5) + 1);
             }
             res = RES_OK;
@@ -466,47 +473,47 @@ DRESULT disk_read (
         }
         break;
 
-      case CTRL_TRIM:   /* Erase a block of sectors (used when _USE_TRIM in ffconf.h is 1) */
-        if (!(CardType & CT_SDC)) break;        /* Check if the card is SDC */
-        if (disk_ioctl(drv, MMC_GET_CSD, csd)) break; /* Get CSD */
-        if (!(csd[0] >> 6) && !(csd[10] & 0x40)) break; /* Check if sector erase can be applied to the card */
-        dp = (DWORD *)buff; st = dp[0]; ed = dp[1];       /* Load sector block */
+      case CTRL_TRIM:                                   // Erase a block of sectors (used when _USE_TRIM in ffconf.h is 1)
+        if (!(CardType & CT_SDC)) break;                // Check if the card is SDC
+        if (disk_ioctl(drv, MMC_GET_CSD, csd)) break;   // Get CSD
+        if (!(csd[0] >> 6) && !(csd[10] & 0x40)) break; // Check if sector erase can be applied to the card
+        dp = (DWORD *)buff; st = dp[0]; ed = dp[1];     // Load sector block
         if (!(CardType & CT_BLOCK)) {
           st *= 512; ed *= 512;
         }
-        if (send_cmd(CMD32, st) == 0 && send_cmd(CMD33, ed) == 0 && send_cmd(CMD38, 0) == 0 && wait_ready(30000)) { /* Erase sector block */
-          res = RES_OK; /* FatFs does not check result of this command */
+        if (send_cmd(CMD32, st) == 0 && send_cmd(CMD33, ed) == 0 && send_cmd(CMD38, 0) == 0 && wait_ready(30000)) { // Erase sector block
+          res = RES_OK; // FatFs does not check result of this command
         }
         break;
 
-      /* Following commands are never used by FatFs module */
+      // The following commands are never used by FatFs module
 
-      case MMC_GET_TYPE:    /* Get MMC/SDC type (BYTE) */
+      case MMC_GET_TYPE:    // Get MMC/SDC type (BYTE)
         *ptr = CardType;
         res = RES_OK;
         break;
 
-      case MMC_GET_CSD:   /* Read CSD (16 bytes) */
-        if (send_cmd(CMD9, 0) == 0 && rcvr_datablock(ptr, 16)) {  /* READ_CSD */
+      case MMC_GET_CSD:     // Read CSD (16 bytes)
+        if (send_cmd(CMD9, 0) == 0 && rcvr_datablock(ptr, 16)) {
           res = RES_OK;
         }
         break;
 
-      case MMC_GET_CID:   /* Read CID (16 bytes) */
-        if (send_cmd(CMD10, 0) == 0 && rcvr_datablock(ptr, 16)) { /* READ_CID */
+      case MMC_GET_CID:     // Read CID (16 bytes)
+        if (send_cmd(CMD10, 0) == 0 && rcvr_datablock(ptr, 16)) {
           res = RES_OK;
         }
         break;
 
-      case MMC_GET_OCR:   /* Read OCR (4 bytes) */
-        if (send_cmd(CMD58, 0) == 0) {  /* READ_OCR */
+      case MMC_GET_OCR:     // Read OCR (4 bytes)
+        if (send_cmd(CMD58, 0) == 0) {
           for (n = 4; n; n--) *ptr++ = xchg_spi(0xFF);
           res = RES_OK;
         }
         break;
 
-      case MMC_GET_SDSTAT:  /* Read SD status (64 bytes) */
-        if (send_cmd(ACMD13, 0) == 0) { /* SD_STATUS */
+      case MMC_GET_SDSTAT:  // Read SD status (64 bytes)
+        if (send_cmd(ACMD13, 0) == 0) {
           xchg_spi(0xFF);
           if (rcvr_datablock(ptr, 64)) res = RES_OK;
         }