added a delay to the resrt slide to allow enough time for graceul closures of the serial port

5 files changed, 53 insertions, 2 deletions

diff --git a/core/usb/usb.c b/core/usb/usb.c
index a8298c0..bbea77d 100644
--- a/core/usb/usb.c
+++ b/core/usb/usb.c
@@ -332,6 +332,42 @@ if (wIstr & ISTR_CTR & wInterrupt_Mask)
     CTR_LP(); /* low priority ISR defined in the usb core lib */
   }
 #endif
+
+/* if we are about to reset from the DTR signal, then dont return
+   to user, instead return from the ISR into a wait slide */
+ if (reset_state == RESET_NOW) {
+   reset_state = START;
+   unsigned int target = (unsigned int)usbWaitReset | 0x1;
+
+   asm volatile("mov r0, %[stack_top]      \n\t"             // Reset the stack
+		"mov sp, r0                \n\t"
+		"mov r0, #1                \n\t"
+		"mov r1, %[target_addr]    \n\t"
+		"mov r2, %[cpsr]           \n\t"
+		"push {r2}                 \n\t"             // Fake xPSR
+		"push {r1}                 \n\t"             // Target address for PC
+		"push {r0}                 \n\t"             // Fake LR
+		"push {r0}                 \n\t"             // Fake R12
+		"push {r0}                 \n\t"             // Fake R3
+		"push {r0}                 \n\t"             // Fake R2
+		"push {r0}                 \n\t"             // Fake R1
+		"push {r0}                 \n\t"             // Fake R0
+		"mov lr, %[exc_return]     \n\t"
+		"bx lr"
+		:
+		: [stack_top] "r" (STACK_TOP),
+		  [target_addr] "r" (target),
+		  [exc_return] "r" (EXC_RETURN),
+		  [cpsr] "r" (DEFAULT_CPSR)
+		: "r0", "r1", "r2");
+   // Should never get here.
+ }
+}
+
+void usbWaitReset(void) {
+  static count=1000000;
+  while (count-- >0);
+  systemHardReset();
 }
 
 /* copies data out of sendBuf into the packet memory for 
diff --git a/core/usb/usb.h b/core/usb/usb.h
index c6377ab..e76772e 100644
--- a/core/usb/usb.h
+++ b/core/usb/usb.h
@@ -48,6 +48,7 @@ typedef enum
 
   /* overloaded ISR routine, this is the main usb ISR */
   void usb_lpIRQHandler(void);
+  void usbWaitReset(void);
 
   /* blocking functions for send/receive */
   int16 usbSendBytes(uint8* sendBuf,uint16 len);
diff --git a/core/usb/usb_callbacks.c b/core/usb/usb_callbacks.c
index f4c491b..08d62c5 100644
--- a/core/usb/usb_callbacks.c
+++ b/core/usb/usb_callbacks.c
@@ -232,11 +232,19 @@ RESULT usbNoDataSetup(u8 request) {
 
         case DTR_NRTS: 
 	  if (new_signal == 0) {
-	    systemHardReset();
+	    /* dont reset here, otherwise
+	       well likely crash the host! */
+	    reset_state = RESET_NOW;
 	  } else {
 	    reset_state = START;
 	  }
 	  break;
+      case RESET_NEXT:
+	reset_state = RESET_NOW;
+	break;
+      case RESET_NOW:
+      /* do nothing, wait for reset */
+	break;
       }
       return USB_SUCCESS;
     }
diff --git a/core/usb/usb_callbacks.h b/core/usb/usb_callbacks.h
index b95ea15..f8a2ef3 100644
--- a/core/usb/usb_callbacks.h
+++ b/core/usb/usb_callbacks.h
@@ -28,7 +28,9 @@ typedef struct {
 typedef enum {
   START,
   NDTR_NRTS,
-  DTR_NRTS
+  DTR_NRTS,
+  RESET_NEXT,
+  RESET_NOW
 } RESET_STATE;
 
 extern RESET_STATE reset_state;  /* tracks DTR/RTS */
diff --git a/core/usb/usb_hardware.h b/core/usb/usb_hardware.h
index 8258da9..208fa3a 100644
--- a/core/usb/usb_hardware.h
+++ b/core/usb/usb_hardware.h
@@ -28,6 +28,10 @@
 #include "usb_type.h"
 
 /* macro'd register and peripheral definitions */
+#define EXC_RETURN 0xFFFFFFF9
+#define DEFAULT_CPSR 0x61000000
+#define STACK_TOP 0x20005000
+
 #define RCC   ((u32)0x40021000)
 #define FLASH ((u32)0x40022000)
 #define GPIOA ((u32)0x40010800)