Enable USB auto-reset in a hard fault.

Redirect thread-mode execution to a fail routine which throbs the LED to
indicate a hard fault. Because the fail routine runs in thread mode
with interrupts on, USB auto-reset should now work. Test by executing
some bogus instruction (e.g. *(volatile int*)0xf34fdaa = 0;) and check
that the auto-reset continues to work.

4 files changed, 39 insertions, 87 deletions

diff --git a/libmaple/exc.c b/libmaple/exc.c
deleted file mode 100644
index a5c67fa..0000000
--- a/libmaple/exc.c
+++ /dev/null
@@ -1,63 +0,0 @@
-

-/* *****************************************************************************

- * The MIT License

- *

- * Copyright (c) 2010 Perry Hung.

- *

- * Permission is hereby granted, free of charge, to any person obtaining a copy

- * of this software and associated documentation files (the "Software"), to deal

- * in the Software without restriction, including without limitation the rights

- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

- * copies of the Software, and to permit persons to whom the Software is

- * furnished to do so, subject to the following conditions:

- *

- * The above copyright notice and this permission notice shall be included in

- * all copies or substantial portions of the Software.

- *

- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

- * THE SOFTWARE.

- * ****************************************************************************/

-

-/**

- * @brief libmaple exception handlers. If DEBUG_LEVEL > DEBUG_FAULT, then these

- * exceptions will ASSERT fail and call into the default _fail() light

- * blinking.

- */

-

-#include "util.h"

-

-void NMIException(void) {

-   ASSERT_FAULT(0);

-   while(1)

-      ;

-}

-

-void HardFaultException(void) {

-   ASSERT_FAULT(0);

-   while(1)

-      ;

-}

-

-void MemManageException(void) {

-   ASSERT_FAULT(0);

-   while(1)

-      ;

-}

-

-void BusFaultException(void) {

-   ASSERT_FAULT(0);

-   while(1)

-      ;

-}

-

-void UsageFaultException(void) {

-   ASSERT_FAULT(0);

-   while(1)

-      ;

-}

-

diff --git a/libmaple/rules.mk b/libmaple/rules.mk
index 8428277..cd50495 100644
--- a/libmaple/rules.mk
+++ b/libmaple/rules.mk
@@ -16,7 +16,6 @@ cSRCS_$(d) := systick.c                \
               timers.c                 \
               adc.c                    \
               syscalls.c               \
-              exc.c                    \
               exti.c                   \
               gpio.c                   \
               nvic.c                   \
@@ -25,8 +24,8 @@ cSRCS_$(d) := systick.c                \
               rcc.c                    \
               flash.c                  \
               spi.c                    \
-			  fsmc.c				   \
-			  dac.c					   \
+              fsmc.c                   \
+              dac.c                    \
               usb/usb.c                \
               usb/usb_callbacks.c      \
               usb/usb_hardware.c       \
@@ -37,12 +36,16 @@ cSRCS_$(d) := systick.c                \
               usb/usb_lib/usb_mem.c    \
               usb/usb_lib/usb_regs.c
 
+sSRCS_$(d) := exc.S
+
 cFILES_$(d) := $(cSRCS_$(d):%=$(d)/%)
+sFILES_$(d) := $(sSRCS_$(d):%=$(d)/%)
 
-OBJS_$(d) := $(cFILES_$(d):%.c=$(BUILD_PATH)/%.o)
+OBJS_$(d) := $(cFILES_$(d):%.c=$(BUILD_PATH)/%.o) $(sFILES_$(d):%.S=$(BUILD_PATH)/%.o)
 DEPS_$(d) := $(OBJS_$(d):%.o=%.d)
 
 $(OBJS_$(d)): TGT_CFLAGS := $(CFLAGS_$(d))
+$(OBJS_$(d)): TGT_ASFLAGS :=
 
 TGT_BIN += $(OBJS_$(d))
 
diff --git a/libmaple/util.c b/libmaple/util.c
index a747948..3325d2b 100644
--- a/libmaple/util.c
+++ b/libmaple/util.c
@@ -68,7 +68,7 @@ void _fail(const char* file, int line, const char* exp) {
     usart_putudec(ERROR_USART_NUM, line);
     usart_putc(ERROR_USART_NUM, '\n');
     usart_putc(ERROR_USART_NUM, '\r');
-    
+
     /* Turn on the error LED  */
     gpio_set_mode(ERROR_LED_PORT, ERROR_LED_PIN, GPIO_MODE_OUTPUT_PP);
 
@@ -77,24 +77,35 @@ void _fail(const char* file, int line, const char* exp) {
     nvic_irq_enable(NVIC_INT_USBLP);
 
     /* Error fade  */
-    while (1) {
-        if (CC == TOP_CNT)  {
-            slope = -1;
-        } else if (CC == 0) {
-            slope = 1;
-        }
-
-        if (i == TOP_CNT)  {
-            CC += slope;
-            i = 0;
-        }
-
-        if (i < CC) {
-            gpio_write_bit(ERROR_LED_PORT, ERROR_LED_PIN, 1);
-        } else {
-            gpio_write_bit(ERROR_LED_PORT, ERROR_LED_PIN, 0);
-        }
-        i++;
-    }
+    throb();
+}
+
+void throb(void) {
+   int32  slope   = 1;
+   uint32 CC      = 0x0000;
+   uint32 TOP_CNT = 0x0200;
+   uint32 i       = 0;
+
+   gpio_set_mode(ERROR_LED_PORT, ERROR_LED_PIN, GPIO_MODE_OUTPUT_PP);
+   /* Error fade  */
+   while (1) {
+      if (CC == TOP_CNT)  {
+         slope = -1;
+      } else if (CC == 0) {
+         slope = 1;
+      }
+
+      if (i == TOP_CNT)  {
+         CC += slope;
+         i = 0;
+      }
+
+      if (i < CC) {
+         gpio_write_bit(ERROR_LED_PORT, ERROR_LED_PIN, 1);
+      } else {
+         gpio_write_bit(ERROR_LED_PORT, ERROR_LED_PIN, 0);
+      }
+      i++;
+   }
 }
 
diff --git a/libmaple/util.h b/libmaple/util.h
index 63e305d..be5e430 100644
--- a/libmaple/util.h
+++ b/libmaple/util.h
@@ -66,6 +66,7 @@ extern "C"{
 #endif
 
 void _fail(const char*, int, const char*);
+void throb(void);
 
 #ifdef __cplusplus
 } // extern "C"