class="markdown_views prism-github-gist"> AP_HAL::Storage
此类可以应用于所有平台。PX4v1平台支持8k的EEPROM，Pixhawk平台支持16k的FRAM铁电存储器 存储大小定义：libraries/AP_HAL/AP_HAL_Boards.h中HAL_STORAGE_SIZE The DataFlash library
DataFlash是用来存储日志的。日志有固定的格式，固定的日志头和日志包头 //`日志头格式` // structure used to define logging format struct LogStructure { uint8_t msg_type; uint8_t msg_len; const char name[5]; const char format[16]; const char labels[64]; }; //`日志包头` #define LOG_PACKET_HEADER uint8_t head1, head2, msgid; 日志举例
libraries/DataFlash/examples/DataFlash_test/DataFlash_test.cpp struct PACKED log_Test { LOG_PACKET_HEADER; uint16_t v1, v2, v3, v4; int32_t l1, l2; }; 日志是以文件的形式存储到microSD card，可以直接拔出SD卡拷贝到PC 每个页首都有“日志文件的编号”和“日志文件的页号”。当用户下载日志时，非常有用 bool DataFlash_Block::WritePrioritisedBlock(const void *pBuffer, uint16_t size, bool is_critical) { // is_critical is ignored - we're a ring buffer and never run out // of space. possibly if we do more complicated bandwidth // limiting we can reservice bandwidth based on is_critical if (!CardInserted() || !log_write_started || !_writes_enabled) { return false; } if (! WriteBlockCheckStartupMessages()) { return false; } while (size > 0) {//while 判断条件 uint16_t n = df_PageSize - df_BufferIdx; if (n > size) { n = size; } if (df_BufferIdx == 0) { // if we are at the start of a page we need to insert a // page header if (n > df_PageSize - sizeof(struct PageHeader)) { n = df_PageSize - sizeof(struct PageHeader); } struct PageHeader ph = { df_FileNumber, df_FilePage };// df_FileNumber, df_FilePage 初始化中从SD卡中读回 add 0xff BlockWrite(df_BufferNum, df_BufferIdx, &ph, sizeof(ph), pBuffer, n);//df_BufferNum 缓存区编号 0/1 df_BufferIdx += n + sizeof(ph); } else { BlockWrite(df_BufferNum, df_BufferIdx, NULL, 0, pBuffer, n); df_BufferIdx += n; } size -= n; pBuffer = (const void *)(n + (uintptr_t)pBuffer); if (df_BufferIdx == df_PageSize) { FinishWrite(); df_FilePage++; } } return true; } 日志按块读写
用户需要设置page大小512 byte，当写满一页以后告诉芯片复制一页 日志本身是通过DataFlash_File.cpp写到SD卡，还提供了DataFlash_Empty.cpp的块设备读写接口，下面是应用铁电的读写实例 //缓冲区buffer static uint8_t buffer[2][DF_PAGE_SIZE]; void DataFlash_Flash::Init(const struct LogStructure *structure, uint8_t num_types) { DataFlash_Backend::Init(structure, num_types); if (flash_fd == 0) { flash_fd = open(MTD_LOG_FILE, O_RDWR, 0777); if (flash_fd == -1) { printf("DataFlash_Flash init failed "); } } df_PageSize = DF_PAGE_SIZE; //页大小 df_NumPages = DF_NUM_PAGES - 1; //页数量 } //读取flash数据到buffer void DataFlash_Flash::PageToBuffer(unsigned char BufferNum, uint16_t PageAdr) { PageAdr -= 1; uint16_t ofs = PageAdr * DF_PAGE_SIZE; memset(buffer[BufferNum], 0, DF_PAGE_SIZE); if (lseek(flash_fd, ofs, SEEK_SET) != ofs) { printf("PageToBuffer lseek err. "); return; } if (read(flash_fd, buffer[BufferNum], DF_PAGE_SIZE) != DF_PAGE_SIZE) { printf("PageToBuffer read err. "); return; } } //记录需要写入flash的页地址和缓冲区编号 void DataFlash_Flash::BufferToPage (unsigned char BufferNum, uint16_t PageAdr, unsigned char wait) { PageAdr -= 1; uint16_t ofs = PageAdr * DF_PAGE_SIZE; if(flash_fd < 0) return; if (lseek(flash_fd, ofs, SEEK_SET) != ofs) { printf("BufferToPage lseek err. "); return; } if (::write(flash_fd, &buffer[BufferNum], DF_PAGE_SIZE) != DF_PAGE_SIZE) { printf("BufferToPage write err. "); return; } } //数据写入缓冲区 void DataFlash_Flash::BlockWrite(uint8_t BufferNum, uint16_t IntPageAdr, const void *pHeader, uint8_t hdr_size, const void *pBuffer, uint16_t size) { if (!_writes_enabled) { return; } memset(&buffer[BufferNum][IntPageAdr], 0, size+hdr_size); if (hdr_size) { memcpy(&buffer[BufferNum][IntPageAdr], pHeader, hdr_size); } memcpy(&buffer[BufferNum][IntPageAdr+hdr_size], pBuffer, size); } //从缓冲区读取数据 bool DataFlash_Flash::BlockRead(uint8_t BufferNum, uint16_t IntPageAdr, void *pBuffer, uint16_t size) { memset(pBuffer, 0, size); memcpy(pBuffer, &buffer[BufferNum][IntPageAdr], size); return true; }