diff --git a/Marlin/src/HAL/HAL_DUE/HAL_spi_Due.cpp b/Marlin/src/HAL/HAL_DUE/HAL_spi_Due.cpp
index 7b5684d6b2..df0d3df4db 100644
--- a/Marlin/src/HAL/HAL_DUE/HAL_spi_Due.cpp
+++ b/Marlin/src/HAL/HAL_DUE/HAL_spi_Due.cpp
@@ -250,7 +250,7 @@
   }
 
   // all the others
-  static uint32_t spiDelayCyclesX4 = (F_CPU/1000000); // 4uS => 125khz
+  static uint32_t spiDelayCyclesX4 = (F_CPU) / 1000000; // 4uS => 125khz
 
   static uint8_t spiTransferX(uint8_t b) { // using Mode 0
     int bits = 8;
@@ -451,77 +451,48 @@
   static pfnSpiTxBlock spiTxBlock = (pfnSpiTxBlock)spiTxBlockX;
   static pfnSpiRxBlock spiRxBlock = (pfnSpiRxBlock)spiRxBlockX;
 
-  #if MB(ALLIGATOR)  // control SDSS pin
-    void spiBegin() {
-      SET_OUTPUT(SS_PIN);
-      WRITE(SS_PIN, HIGH);
-      SET_OUTPUT(SCK_PIN);
-      SET_INPUT(MISO_PIN);
-      SET_OUTPUT(MOSI_PIN);
-    }
-
-    uint8_t spiRec() {
-      WRITE(SS_PIN, LOW);
-      WRITE(MOSI_PIN, 1); /* Output 1s 1*/
-      uint8_t b = spiTransferRx(0xFF);
-      WRITE(SS_PIN, HIGH);
-      return b;
-    }
-
-    void spiRead(uint8_t* buf, uint16_t nbyte) {
-      uint32_t todo = nbyte;
-      if (todo == 0) return;
-
-      WRITE(SS_PIN, LOW);
-      WRITE(MOSI_PIN, 1); /* Output 1s 1*/
-      spiRxBlock(buf,nbyte);
-      WRITE(SS_PIN, HIGH);
-    }
-
-    void spiSend(uint8_t b) {
-      WRITE(SS_PIN, LOW);
-      (void) spiTransferTx(b);
-      WRITE(SS_PIN, HIGH);
-    }
-
-    void spiSendBlock(uint8_t token, const uint8_t* buf) {
-      WRITE(SS_PIN, LOW);
-      (void) spiTransferTx(token);
-      spiTxBlock(buf,512);
-      WRITE(SS_PIN, HIGH);
-
-  #else   // let calling routine control SDSS
-    void spiBegin() {
-      SET_OUTPUT(SS_PIN);
-      SET_OUTPUT(SCK_PIN);
-      SET_INPUT(MISO_PIN);
-      SET_OUTPUT(MOSI_PIN);
-    }
-
-    uint8_t spiRec() {
-      WRITE(MOSI_PIN, 1); /* Output 1s 1*/
-      uint8_t b = spiTransferRx(0xFF);
-      return b;
-    }
-
-    void spiRead(uint8_t* buf, uint16_t nbyte) {
-      uint32_t todo = nbyte;
-      if (todo == 0) return;
+  #if MB(ALLIGATOR)
+    #define _SS_WRITE(S) WRITE(SS_PIN, S)
+  #else
+    #define _SS_WRITE(S) NOOP
+  #endif
+
+  void spiBegin() {
+    SET_OUTPUT(SS_PIN);
+    _SS_WRITE(HIGH);
+    SET_OUTPUT(SCK_PIN);
+    SET_INPUT(MISO_PIN);
+    SET_OUTPUT(MOSI_PIN);
+  }
 
-      WRITE(MOSI_PIN, 1); /* Output 1s 1*/
-      spiRxBlock(buf,nbyte);
-    }
+  uint8_t spiRec() {
+    _SS_WRITE(LOW);
+    WRITE(MOSI_PIN, HIGH); // Output 1s 1
+    uint8_t b = spiTransferRx(0xFF);
+    _SS_WRITE(HIGH);
+    return b;
+  }
 
-    void spiSend(uint8_t b) {
-      (void) spiTransferTx(b);
+  void spiRead(uint8_t* buf, uint16_t nbyte) {
+    if (nbyte) {
+      _SS_WRITE(LOW);
+      WRITE(MOSI_PIN, HIGH); // Output 1s 1
+      spiRxBlock(buf, nbyte);
+      _SS_WRITE(HIGH);
     }
+  }
 
-    void spiSendBlock(uint8_t token, const uint8_t* buf) {
-      (void) spiTransferTx(token);
-      spiTxBlock(buf,512);
-
-    #endif
+  void spiSend(uint8_t b) {
+    _SS_WRITE(LOW);
+    (void)spiTransferTx(b);
+    _SS_WRITE(HIGH);
+  }
 
+  void spiSendBlock(uint8_t token, const uint8_t* buf) {
+    _SS_WRITE(LOW);
+    (void)spiTransferTx(token);
+    spiTxBlock(buf, 512);
+    _SS_WRITE(HIGH);
   }
 
   /**
@@ -549,7 +520,7 @@
         spiRxBlock = (pfnSpiRxBlock)spiRxBlockX;
         break;
       default:
-        spiDelayCyclesX4 = (F_CPU/1000000) >> (6 - spiRate);
+        spiDelayCyclesX4 = ((F_CPU) / 1000000) >> (6 - spiRate);
         spiTransferTx = (pfnSpiTransfer)spiTransferX;
         spiTransferRx = (pfnSpiTransfer)spiTransferX;
         spiTxBlock = (pfnSpiTxBlock)spiTxBlockX;
@@ -557,9 +528,7 @@
         break;
     }
 
-    #if MB(ALLIGATOR)
-      WRITE(SS_PIN, HIGH);
-    #endif
+    _SS_WRITE(HIGH);
     WRITE(MOSI_PIN, HIGH);
     WRITE(SCK_PIN, LOW);
   }
@@ -573,6 +542,10 @@
 
 #else // !SOFTWARE_SPI
 
+  #define WHILE_TX(N) while ((SPI0->SPI_SR & SPI_SR_TDRE) == (N))
+  #define WHILE_RX(N) while ((SPI0->SPI_SR & SPI_SR_RDRF) == (N))
+  #define FLUSH_TX() do{ WHILE_RX(1) SPI0->SPI_RDR; }while(0)
+
   #if MB(ALLIGATOR)
 
     // slave selects controlled by SPI controller
@@ -645,13 +618,14 @@
       WRITE(SPI_FLASH_CS, HIGH);
       WRITE(SS_PIN, HIGH);
 
-      OUT_WRITE(SDSS,0);
+      OUT_WRITE(SDSS, LOW);
 
       PIO_Configure(
         g_APinDescription[SPI_PIN].pPort,
         g_APinDescription[SPI_PIN].ulPinType,
         g_APinDescription[SPI_PIN].ulPin,
-        g_APinDescription[SPI_PIN].ulPinConfiguration);
+        g_APinDescription[SPI_PIN].ulPinConfiguration
+      );
 
       spiInit(1);
     }
@@ -660,30 +634,23 @@
     uint8_t spiRec() {
       // write dummy byte with address and end transmission flag
       SPI0->SPI_TDR = 0x000000FF | SPI_PCS(SPI_CHAN) | SPI_TDR_LASTXFER;
-      // wait for transmit register empty
-      while ((SPI0->SPI_SR & SPI_SR_TDRE) == 0);
 
-      // wait for receive register
-      while ((SPI0->SPI_SR & SPI_SR_RDRF) == 0);
-      // get byte from receive register
+      WHILE_TX(0);
+      WHILE_RX(0);
+
       //DELAY_US(1U);
       return SPI0->SPI_RDR;
     }
 
     uint8_t spiRec(uint32_t chan) {
-      uint8_t spirec_tmp;
-      // wait for transmit register empty
-      while ((SPI0->SPI_SR & SPI_SR_TDRE) == 0);
-      while ((SPI0->SPI_SR & SPI_SR_RDRF) == 1)
-        spirec_tmp =  SPI0->SPI_RDR;
-        UNUSED(spirec_tmp);
+
+      WHILE_TX(0);
+      FLUSH_RX();
 
       // write dummy byte with address and end transmission flag
       SPI0->SPI_TDR = 0x000000FF | SPI_PCS(chan) | SPI_TDR_LASTXFER;
+      WHILE_RX(0);
 
-      // wait for receive register
-      while ((SPI0->SPI_SR & SPI_SR_RDRF) == 0);
-      // get byte from receive register
       return SPI0->SPI_RDR;
     }
 
@@ -692,9 +659,9 @@
       if (nbyte-- == 0) return;
 
       for (int i = 0; i < nbyte; i++) {
-        //while ((SPI0->SPI_SR & SPI_SR_TDRE) == 0);
+        //WHILE_TX(0);
         SPI0->SPI_TDR = 0x000000FF | SPI_PCS(SPI_CHAN);
-        while ((SPI0->SPI_SR & SPI_SR_RDRF) == 0);
+        WHILE_RX(0);
         buf[i] = SPI0->SPI_RDR;
         //DELAY_US(1U);
       }
@@ -705,11 +672,8 @@
     void spiSend(byte b) {
       // write byte with address and end transmission flag
       SPI0->SPI_TDR = (uint32_t)b | SPI_PCS(SPI_CHAN) | SPI_TDR_LASTXFER;
-      // wait for transmit register empty
-      while ((SPI0->SPI_SR & SPI_SR_TDRE) == 0);
-      // wait for receive register
-      while ((SPI0->SPI_SR & SPI_SR_RDRF) == 0);
-      // clear status
+      WHILE_TX(0);
+      WHILE_RX(0);
       SPI0->SPI_RDR;
       //DELAY_US(1U);
     }
@@ -718,8 +682,8 @@
       if (n == 0) return;
       for (size_t i = 0; i < n - 1; i++) {
         SPI0->SPI_TDR = (uint32_t)buf[i] | SPI_PCS(SPI_CHAN);
-        while ((SPI0->SPI_SR & SPI_SR_TDRE) == 0);
-        while ((SPI0->SPI_SR & SPI_SR_RDRF) == 0);
+        WHILE_TX(0);
+        WHILE_RX(0);
         SPI0->SPI_RDR;
         //DELAY_US(1U);
       }
@@ -727,29 +691,20 @@
     }
 
     void spiSend(uint32_t chan, byte b) {
-      uint8_t dummy_read = 0;
-      // wait for transmit register empty
-      while ((SPI0->SPI_SR & SPI_SR_TDRE) == 0);
+      WHILE_TX(0);
       // write byte with address and end transmission flag
       SPI0->SPI_TDR = (uint32_t)b | SPI_PCS(chan) | SPI_TDR_LASTXFER;
-      // wait for receive register
-      while ((SPI0->SPI_SR & SPI_SR_RDRF) == 0);
-      // clear status
-      while ((SPI0->SPI_SR & SPI_SR_RDRF) == 1)
-        dummy_read = SPI0->SPI_RDR;
-      UNUSED(dummy_read);
+      WHILE_RX(0);
+      FLUSH_RX();
     }
 
     void spiSend(uint32_t chan, const uint8_t* buf, size_t n) {
-      uint8_t dummy_read = 0;
       if (n == 0) return;
       for (int i = 0; i < (int)n - 1; i++) {
-        while ((SPI0->SPI_SR & SPI_SR_TDRE) == 0);
+        WHILE_TX(0);
         SPI0->SPI_TDR = (uint32_t)buf[i] | SPI_PCS(chan);
-        while ((SPI0->SPI_SR & SPI_SR_RDRF) == 0);
-        while ((SPI0->SPI_SR & SPI_SR_RDRF) == 1)
-          dummy_read = SPI0->SPI_RDR;
-        UNUSED(dummy_read);
+        WHILE_RX(0);
+        FLUSH_RX();
       }
       spiSend(chan, buf[n - 1]);
     }
@@ -757,13 +712,13 @@
     // Write from buffer to SPI
     void spiSendBlock(uint8_t token, const uint8_t* buf) {
       SPI0->SPI_TDR = (uint32_t)token | SPI_PCS(SPI_CHAN);
-      while ((SPI0->SPI_SR & SPI_SR_TDRE) == 0);
-      //while ((SPI0->SPI_SR & SPI_SR_RDRF) == 0);
+      WHILE_TX(0);
+      //WHILE_RX(0);
       //SPI0->SPI_RDR;
       for (int i = 0; i < 511; i++) {
         SPI0->SPI_TDR = (uint32_t)buf[i] | SPI_PCS(SPI_CHAN);
-        while ((SPI0->SPI_SR & SPI_SR_TDRE) == 0);
-        while ((SPI0->SPI_SR & SPI_SR_RDRF) == 0);
+        WHILE_TX(0);
+        WHILE_RX(0);
         SPI0->SPI_RDR;
         //DELAY_US(1U);
       }
@@ -792,7 +747,7 @@
 
       // Disable PIO on A26 and A27
       REG_PIOA_PDR = 0x0C000000;
-      OUT_WRITE(SDSS, 1);
+      OUT_WRITE(SDSS, HIGH);
 
       // Reset SPI0 (from sam lib)
       SPI0->SPI_CR = SPI_CR_SPIDIS;
@@ -807,45 +762,30 @@
       SPI0->SPI_CSR[3] = SPI_CSR_SCBR(spiDivider[spiRate]) | SPI_CSR_CSAAT | SPI_MODE_0_DUE_HW;  // use same CSR as TMC2130
     }
 
-    void spiBegin() {
-      spiInit();
-    }
+    void spiBegin() { spiInit(); }
 
     static uint8_t spiTransfer(uint8_t data) {
-
-      // Wait until tx register is empty
-      while( (SPI0->SPI_SR & SPI_SR_TDRE) == 0 );
-      // Send data
+      WHILE_TX(0);
       SPI0->SPI_TDR = (uint32_t)data | 0x00070000UL;  // Add TMC2130 PCS bits to every byte
-
-      // wait for transmit register empty
-      while ((SPI0->SPI_SR & SPI_SR_TDRE) == 0);
-
-      // wait for receive register
-      while ((SPI0->SPI_SR & SPI_SR_RDRF) == 0);
-      // get byte from receive register
+      WHILE_TX(0);
+      WHILE_RX(0);
       return SPI0->SPI_RDR;
     }
 
-    uint8_t spiRec() {
-      uint8_t data = spiTransfer(0xFF);
-      return data;
-    }
+    uint8_t spiRec() { return (uint8_t)spiTransfer(0xFF); }
 
     void spiRead(uint8_t* buf, uint16_t nbyte) {
-      if (nbyte == 0) return;
-      for (int i = 0; i < nbyte; i++)
-        buf[i] = spiTransfer(0xFF);
+      if (nbyte)
+        for (int i = 0; i < nbyte; i++)
+          buf[i] = spiTransfer(0xFF);
     }
 
-    void spiSend(uint8_t data) {
-      spiTransfer(data);
-    }
+    void spiSend(uint8_t data) { spiTransfer(data); }
 
-    void spiSend(const uint8_t* buf, size_t n) {
-      if (n == 0) return;
-      for (uint16_t i = 0; i < n; i++)
-        spiTransfer(buf[i]);
+    void spiSend(const uint8_t* buf, size_t nbyte) {
+      if (nbyte)
+        for (uint16_t i = 0; i < nbyte; i++)
+          spiTransfer(buf[i]);
     }
 
     void spiSendBlock(uint8_t token, const uint8_t* buf) {