Bootloader: add 3 LED blinks on boot

Replaces #12

Author: facchinm

bootloaders/atmega4809_uart_bl.hex

@@ -1,19 +1,20 @@
-:10000000112480911F138B3E09F05FC08FEF809306
-:100010001F1393E08DE984BF90930010809102102C
-:1000200081FDFCCF80EC80930608A09123110A2E5D
-:10003000000CBB0BBC5F2CE530E00E946C00DC01C7
-:10004000CB019E5FAF4FBF4F2AE0B595A79597951F
-:1000500087952A95D1F78093080890930908809195
-:10006000E20581608093E205049A669AE0E0F2E49A
-:100070002DE933E040E41EC08091040887FFFCCFE7
-:1000800080910008E11552E4F50711F4882391F0FE
-:10009000809302088193CF018F779927892B51F4A0
-:1000A00024BF309300108091021080FDFCCF8DB1F1
-:1000B00084278DB9CF0190548115904CE8F291E0DE
-:1000C00088ED84BF9093410007C082E080930110C7
-:1000D000E0E0F1E00995A6CF0E947300B7FF089514
-:1000E000821B930B0895A29FB001B39FC001A39FF1
-:1000F000700D811D1124911DB29F700D811D112461
-:04010000911D0895B0
+:100000001124669A26E030E408C000000197E9F761
+:100010008DB183278DB9215019F081E091E7F6CF9A
+:1000200080911F138B3E69F48FEF80931F138DE92E
+:1000300093E084BF909300108091021081FDFCCF6B
+:1000400006C082E080930110E0E0F1E0099580ECC9
+:1000500080930608A09123110A2E000CBB0BBC5FF5
+:100060002CE530E00E9476007E5F8F4F9F4F2AE0A4
+:1000700095958795779567952A95D1F760930808A8
+:10008000709309088091E20581608093E205049AEB
+:10009000E0E0F2E42DE933E040E41EC08091040882
+:1000A00087FFFCCF80910008E11552E4F50711F4B9
+:1000B000882391F0809302088193CF018F7799274D
+:1000C000892B51F424BF309300108091021080FDE1
+:1000D000FCCF8DB184278DB9CF0190548115904C00
+:1000E000E8F288ED91E084BF909341000E947D008A
+:1000F000B7FF0895821B930B0895A29FB001B39F91
+:10010000C001A39F700D811D1124911DB29F700D20
+:08011000811D1124911D0895C9
 :02000004008278
 :00000001FF

bootloaders/boot.c

@@ -77,6 +77,7 @@ static inline uint8_t uart_receive(void);
 static inline void uart_send(uint8_t byte);
 static inline void init_status_led(void);
 static inline void toggle_status_led(void);
+static inline void wait_50_ms(void);
 
 /*
  * Main boot function
@@ -88,6 +89,13 @@ __attribute__((naked)) __attribute__((section(".ctors"))) void boot(void)
   /* Initialize system for AVR GCC support, expects r1 = 0 */
   asm volatile("clr r1");
 
+  /* 3 very fast blinks (to match optiboot behaviour) */
+  init_status_led();
+  for (uint8_t i = 0; i < 6; i++) {
+    wait_50_ms();
+    toggle_status_led();
+  }
+
   /* Check if entering application or continuing to bootloader */
   if(!is_bootloader_requested()) {
     /* Enable Boot Section Lock */
@@ -100,7 +108,6 @@ __attribute__((naked)) __attribute__((section(".ctors"))) void boot(void)
 
   /* Initialize communication interface */
   init_uart();
-  init_status_led();
 
   /*
    * Start programming at start for application section
@@ -199,3 +206,10 @@ static inline void toggle_status_led(void)
   /* Toggle LED0 (PD6) */
   VPORTD.OUT ^= PIN6_bm;
 }
+
+static inline void wait_50_ms(void)
+{
+  for (uint16_t i = 160000; i--; i != 0) {
+    asm volatile ("nop");
+  }
+}

bootloaders/build.sh

@@ -15,4 +15,4 @@ ${AVR_GCC_PATH}/avr-objcopy -O ihex -R .fuses boot.elf boot.hex
 echo Moving hex
 mv boot.hex atmega4809_uart_bl.hex
 
-${AVR_GCC_PATH}/../avrdude/6.3.0-arduino14/bin/avrdude -C${AVR_GCC_PATH}/../avrdude/6.3.0-arduino14/etc/avrdude.conf -v -patmega4809 -cxplainedmini_updi -Pusb -Ufuses:w:boot.fuses:r  -Uflash:w:boot.bin:r
+#${AVR_GCC_PATH}/../avrdude/6.3.0-arduino14/bin/avrdude -C${AVR_GCC_PATH}/../avrdude/6.3.0-arduino14/etc/avrdude.conf -v -patmega4809 -cxplainedmini_updi -Pusb -Ufuses:w:boot.fuses:r  -Uflash:w:boot.bin:r