{
  "kind": "合成输入与数学模型输出，非设备实测",
  "article": "https://qifudev.com/article/spi-dma-overhead-measure/",
  "tool": "https://qifudev.com/tools/spi-budget/",
  "formula": "t线 = (命令位 + 地址位 + dummy周期 + 8 × 载荷字节) / fSCLK",
  "inputs": [
    {
      "name": "SPI 时钟",
      "key": "clockMhz",
      "value": 8,
      "unit": "MHz"
    },
    {
      "name": "载荷长度",
      "key": "payloadBytes",
      "value": 64,
      "unit": "byte"
    },
    {
      "name": "命令阶段",
      "key": "commandBits",
      "value": 8,
      "unit": "bit"
    },
    {
      "name": "地址阶段",
      "key": "addressBits",
      "value": 24,
      "unit": "bit"
    },
    {
      "name": "dummy时钟数",
      "key": "dummyBits",
      "value": 0,
      "unit": "cycle"
    },
    {
      "name": "每事务额外间隙",
      "key": "gapUs",
      "value": 30,
      "unit": "μs"
    }
  ],
  "outputs": [
    {
      "name": "单事务占线时间",
      "key": "transmitUs",
      "value": 68,
      "unit": "μs"
    },
    {
      "name": "含间隙的事务周期",
      "key": "totalUs",
      "value": 98,
      "unit": "μs"
    },
    {
      "name": "单向有效载荷速度",
      "key": "payloadRate",
      "value": 653061.224489796,
      "unit": "byte/s"
    }
  ],
  "warnings": [],
  "assumptions": "不用于Dual、Quad、Octal或DDR模式，不包含设备busy等待、DMA建链、内存复制和多设备争用的自动模型。间隙值需要由真实事务测量补充。",
  "source": {
    "label": "乐鑫 SPI Master：事务与性能",
    "url": "https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-reference/peripherals/spi_master.html"
  },
  "measured": {
    "device": null,
    "firmware": null,
    "environment": null,
    "instrument": null,
    "result": null,
    "verdict": null
  }
}