airbourne/airbourne/examples/backup_sram/main.cpp
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1 /*
2  * Copyright (c) 2017, James Jackson
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12  * * Redistributions in binary form must reproduce the above copyright notice,
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18  * this software without specific prior written permission.
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31 
32 #include "backup_sram.h"
33 #include "led.h"
34 #include "printf.h"
35 #include "pwm.h"
36 #include "revo_f4.h"
37 #include "system.h"
38 #include "vcp.h"
39 
40 #include <string>
41 
42 struct BackupData
43 {
44  static constexpr uint32_t CHECKSUM_START = 0xA5A5;
45 
46  uint32_t reset_count;
47  uint32_t some_data;
48  uint32_t checksum;
49 
50  BackupData() { memset(this, 0, sizeof(BackupData)); }
51 
52  uint32_t compute_checksum()
53  {
54  uint32_t crc = CHECKSUM_START;
55  for (size_t offset = 0; offset <= sizeof(BackupData) - sizeof(checksum) - sizeof(crc); offset++)
56  {
57  crc ^= *reinterpret_cast<uint32_t*>(reinterpret_cast<uint8_t*>(this) + offset);
58  }
59  return crc;
60  }
61 };
62 
63 void restart()
64 {
66 }
67 
68 int main()
69 {
70  systemInit();
71  VCP vcp;
72  vcp.init();
74 
75  // check for and process backup data if it exists
76  BackupData read_data;
77  backup_sram_read(&read_data, sizeof(read_data));
78 
79  uint32_t reset_count = 0;
80  if (read_data.checksum == read_data.compute_checksum())
81  reset_count = read_data.reset_count;
82 
83  // clear the backup data so it doesn't get read on normal startup
85 
86  // Pretend we get a hardfault some time in the future; write backup data and reset.
87  // Normally this would be done in the hardfault interrupt handler.
88  delay(300);
89 
90  BackupData write_data;
91  write_data.reset_count = ++reset_count; // increment reset counter
92  write_data.some_data = 0xDEADBEEF;
93  write_data.checksum = write_data.compute_checksum();
94  backup_sram_write(&write_data, sizeof(write_data));
95 
96  restart();
97 }
void systemInit(void)
Definition: system.c:55
static constexpr uint32_t CHECKSUM_START
void backup_sram_init()
Definition: backup_sram.cpp:8
void init()
Definition: vcp.cpp:24
void backup_sram_read(void *dst, size_t len)
Definition: backup_sram.cpp:29
__STATIC_INLINE void NVIC_SystemReset(void)
System Reset.
Definition: core_cm0.h:647
Definition: vcp.h:19
void backup_sram_write(const void *src, size_t len)
Definition: backup_sram.cpp:19
void backup_sram_clear(size_t len)
Definition: backup_sram.cpp:37
void delay(uint32_t ms)
Definition: system.c:101


rosflight_firmware
Author(s): Daniel Koch , James Jackson
autogenerated on Fri Jul 24 2020 03:20:08