# HG changeset patch
# User Ethan Zonca <ez@ethanzonca.com>
# Date 2015-01-24 16:19:18
# Node ID c14060ecae42071e8a4d776bd1f51a363ed7c5eb
# Parent  ab7abb62e433a209f860409593c05105056569ee

Added initial prototype of jump-to-bootloader

diff --git a/main.c b/main.c
--- a/main.c
+++ b/main.c
@@ -65,7 +65,10 @@ SPI_HandleTypeDef hspi1;
 static __IO uint32_t TimingDelay;
 
 
-
+void deinit(void)
+{
+    HAL_DeInit();
+}
 
 volatile int i=0;
 int main(void)
@@ -519,8 +522,17 @@ void machine()
                         state = STATE_SETP;
                         break;
                     case 0:
+                    {
+                        ssd1306_clearscreen();
+                        ssd1306_DrawString("Entering Bootloader", 1, 0);
+                        ssd1306_DrawString("(hopefully)", 2, 0);
+                        HAL_Delay(1000);
+                        *((unsigned long *)0x200017F0) = 0xDEADBEEF; // 6KB STM32F042
+                        NVIC_SystemReset();
+
                         state = STATE_IDLE;
-                        break;
+                    } break;
+
                     default:
                         state = STATE_PREHEAT_BREW;
                 }
diff --git a/startup_stm32f042x6.s b/startup_stm32f042x6.s
--- a/startup_stm32f042x6.s
+++ b/startup_stm32f042x6.s
@@ -64,6 +64,17 @@ defined in linker script */
   .weak Reset_Handler
   .type Reset_Handler, %function
 Reset_Handler:
+
+  /* Bootloader jumping */
+  ldr r0, =0x200017F0 /* address of magic token, is addr within memory range? */
+  ldr r1, =0xDEADBEEF /* magical beef token */
+  ldr r2, [r0, #0] /* load data from magic address */
+  str r0, [r0, #0] /* zero data at magic address so we don't bootloop */ 
+  cmp r2, r1 /* compare data at magic address to magic token */
+  beq Reboot_Loader /* jump to bootloader if token match */
+  /* End bootloader jumping */
+
+
   ldr   r0, =_estack
   mov   sp, r0          /* set stack pointer */
 
@@ -71,6 +82,19 @@ Reset_Handler:
   movs r1, #0
   b LoopCopyDataInit
 
+/* Boot into bootloader */
+Reboot_Loader:
+  ldr r0, =0x1FFFF6A6 /* Address of bootloader on f042 from CD00167594 pg 15 table 3 */
+  /* This replaces ldr sp, [r0, #0] which doesn't work on m0 */
+  // Set stack pointer
+  ldr r1, [r0, #0]
+  mov sp, r1
+
+  // Branch to bootloader
+  ldr r0, [r0, #4]
+  bx r0
+
+
 CopyDataInit:
   ldr r3, =_sidata
   ldr r3, [r3, r1]