7 固件实现

系统架构

主环路状态机：

图 7-1 固件状态机图. 显示主应用程序循环和中断处理程序的固件状态机图

外设配置

使用 TI SysConfig 配置 MSPM0G5187 外设。密钥设置：

ADC 数据采集

乒乓缓冲器策略

/* ADC Ping-Pong Buffers */
int16_t gADCSamplesPing[ADC_SAMPLE_SIZE]; // 512 samples
int16_t gADCSamplesPong[ADC_SAMPLE_SIZE]; // 512 samples

volatile bool gPing = true;      // Current buffer indicator
volatile bool gCheckADC = false; // New data ready flag

DMA 填充一个缓冲区，同时 CPU 处理另一个缓冲区，从而实现连续采样。

Log 300 数据扩展

/* Scales ADC samples and converts them to Q15 format */
void adc_q15_scale(int16_t *samples)
{
    int16_t shift = 2048;  // Mid-scale for 12-bit ADC
    for (int i = 0; i < ADC_SAMPLE_SIZE; ++i)
    {
        // Convert from unsigned 12-bit to signed Q15
        // Shift of 4 provides 16x gain for better SNR
        samples[i] = samples[i]*8
    }
}

特征提取

#include "feature_extract.h"

// Initialize feature extraction (call once at startup)
FE_init();

// Process each frame of ADC samples
FE_process(newSamples, gNewFeatures, 0);  // varIndex=0 for single channel

NPU 推理

/* NPU Initialization */
DL_NPU_reset(NPU);
DL_NPU_enablePower(NPU);
while (!(DL_SYSCTL_getStatus() & DL_SYSCTL_STATUS_NPU_READY));

/* Input/Output tensor structures */
struct tvmgen_default_inputs tvm_if_map = { (void*) &gIF_Map[0] };
struct tvmgen_default_outputs tvm_of_map = { (void*) &gOF_Map[0] };

/* Run inference */
tvmgen_default_run(&tvm_if_map, &tvm_of_map);

/* Wait for completion */
while (!tvmgen_default_finished) { __WFE(); }

/* Output: gOF_Map[0][0] = arc confidence, gOF_Map[0][1] = normal confidence */

跳闸逻辑（表决算法）

#define INFERENCE_FRAME_THRESHOLD_FOR_ARC 5

/* Circular buffer for predictions */
volatile uint8_t gPredVector[8] = {0};
volatile uint8_t gPredPtr = 0;
volatile uint16_t gPredSum = 0;

int trip_logic(int inf)
{
    /* Update circular buffer */
    gPredSum -= gPredVector[gPredPtr];

    if (inf >= 0) {
        gPredVector[gPredPtr] = 1;
        gPredSum += 1;
    } else {
        gPredVector[gPredPtr] = 0;
    }

    gPredPtr = (gPredPtr + 1) % 8;

    /* Majority voting: 5 out of 8 frames must detect arc */
    return (gPredSum > INFERENCE_FRAME_THRESHOLD_FOR_ARC) ? 1 : 0;
}