分类： 摄影番外

一、改造目标与思路

Nikon F90X / N90S 采用一套复杂的机制，来进行过片控制。

6. 胶片进片（过片）

1. 当参考开关（也就是我们监测的ref）断开四次（相当于四个画幅）时，自动装片操作停止。
2. 参考开关始终保持在导通状态。该开关在胶片每进给约 19 mm（半幅）时断开一次。
3. 当参考开关断开后，监测胶片进片光电遮断器（intp）的脉冲输出，进片停止定时控制开始。
4. 胶片进片光电遮断器在进给一个画幅期间输出 114 个脉冲。

在一般状态下，正常全画幅过片约 114 个 INTP （光遮断传感器，其与卷片齿轮耦合，INTK点亮，监测传感器通过齿孔旋转，在不断的遮断/打开之间获得脉冲，来计算过片量）脉冲。

方画幅 / 半格改造需要在胶片走到约 5/8 位置（实测约 71 脉冲，可配置为 50 等）时强行停住，让机身认为本帧结束。

经过测试，单纯修改RAM地址 FE7E 为 71、或伪造 REF不能稳定实现方画幅；

一个可行的路径是：检测INTP 计数到目标值 → 提前拉停 IN1/IN2 → 进入END状态→用串口清 RAM 残留态→松刹进入下一张待命。

因此，通过监测真实的INTP，并电控拉停IN1/IN2，我们可以实现比较精确的过片量控制，从而任意实现半格/方格乃至N格的控制。

二、硬件连接

因为机身请求5V IO控制，所以本次试验我们采用了Arduino Uno进行控制。

刹停采用开漏拉低（BRAKE_OPEN_DRAIN=1），松刹时引脚改回输入，由机身上拉释放电机。

附件口协议与 Nikon 官方附件一致：1200 bps 唤醒 → S1000 识别 → 9600 bps → 0x80 读 RAM / 0x81 写 RAM。

三、反编译ROM得到的RAM变量含义

3.1 关键 RAM 变量

外刹停住物理胶片后，机身 MCU 仍认为过片进行中：

• FED4.1 常为 1
• FE7D 停在 ~47（71 脉冲附近）
• FEE1 继续向 200ms 超时计数
• 若不干预 → FE4E=0x23，LCD 显示 End

因此我们可以通过串口对特定地址的RAM进行复位。

四、UNO卷片控制固件架构

Uno代码：

/*
 * F90X 卷片控制 — v17.0
 *
 * D2=INTP  D6/D7=IN1/IN2  机身TX→D10 RX←D11  GND
 * USB 115200：r/p  x  w  c  b  e  l  h
 */

#include "f90x_cam_serial.h"

#define FW_VERSION         "v17.2"

#ifndef AUTO_RELEASE_BRAKE_ON_X
#define AUTO_RELEASE_BRAKE_ON_X  1
#endif

#define PIN_INTP      2
#define PIN_IN1       6
#define PIN_IN2       7

#define BRAKE_OPEN_DRAIN  1

const uint8_t  BRAKE_AT          = 71;
const uint16_t BRAKE_CLR_SETTLE_MS = 100;
const uint16_t POST_CLR_GAP_MS   = 40;

const uint16_t LATCH_END_POLL_MS = 2000;
const uint16_t LATCH_END_FAIL_MS = 8000;
const uint16_t LATCH_SERIAL_DEFER_MS = 500;

const uint8_t  ARM_PULSES        = 5;
const uint8_t  ARM_PULSES_LATCH  = 3;
const uint16_t ARM_WINDOW_MS     = 120;
const uint16_t CONFIRM_MS        = 80;
const uint16_t COOLDOWN_MS       = 300;
const uint16_t BOOT_MS           = 1000;
const uint16_t PREBOOT_RETRY_MS  = 15000;
const uint16_t PREBOOT_FAIL_MS   = 3000;
const uint16_t LOAD_BLOCK_POLL_MS = 1000;
const uint8_t  LATCH_STUCK_FAIL_N = 3;

enum State { ST_BOOT, ST_IDLE, ST_ARM, ST_RUN, ST_HOLD, ST_LATCH };

volatile State    gSt     = ST_BOOT;
volatile uint16_t gCnt    = 0;
volatile uint32_t gArmUs  = 0;
volatile bool     gCamBusy = false;

uint32_t gBootMs            = 0;
uint32_t gLastIntpMs        = 0;
uint32_t gCoolUntilMs       = 0;
uint32_t gHoldStartMs       = 0;
uint32_t gBrakeClrDoneMs    = 0;
uint32_t gLastEndPollMs     = 0;
uint32_t gLatchQuietUntilMs = 0;
uint8_t  gArmN              = 0;
uint8_t  gCntAtBrake        = 0;

bool gBrakeClrPending       = false;
bool gBrakeClrDone          = false;
bool gBrakeClrVerified      = false;

static volatile bool gFromLatch = false;
static volatile bool gBlockArmForLoad = false;

uint32_t gLastPrebootMs = 0;
uint32_t gLastLoadPollMs = 0;
bool     gEndProbeDone    = false;
uint8_t  gLatchClrFailN   = 0;

void onIntp();

static void printHexByte(uint8_t v) {
  if (v < 0x10) Serial.print('0');
  Serial.print(v, HEX);
}

static void printHexBuf(const uint8_t *buf, uint8_t len) {
  for (uint8_t i = 0; i < len; i++) {
    if (i) Serial.print(' ');
    printHexByte(buf[i]);
  }
}

static bool printWindErrorDiag() {
  uint8_t b = 0;
  uint16_t w = 0;
  bool ok = true;

  Serial.print(F("WIND "));
  if (f90xCamReadByte(0xFE4E, &b)) {
    Serial.print(F(" FE4E=0x"));
    printHexByte(b);
  } else ok = false;
  delay(25);

  if (f90xCamReadByte(0xFEE1, &b)) {
    Serial.print(F(" FEE1=0x"));
    printHexByte(b);
  } else ok = false;
  delay(25);

  if (f90xCamReadByte(0xFE7D, &b)) {
    Serial.print(F(" FE7D=0x"));
    printHexByte(b);
  } else ok = false;
  delay(25);

  if (f90xCamReadByte(0xFE7E, &b)) {
    Serial.print(F(" FE7E=0x"));
    printHexByte(b);
  } else ok = false;
  delay(25);

  if (f90xCamReadWord(0xFEE4, &w)) {
    Serial.print(F(" FEE4=0x"));
    printHexByte((uint8_t)(w & 0xFF));
    printHexByte((uint8_t)(w >> 8));
  } else ok = false;

  if (!ok) {
    Serial.print(F(" (partial)"));
    f90xCamPrintLastRx();
  }
  Serial.println();
  return ok;
}

static void printAdvanceChainExtra() {
  uint8_t feb0 = 0, feb2 = 0, fe40 = 0, fed5 = 0, fed7 = 0, feb5 = 0, fe47 = 0;
  uint8_t fe9f = 0, fe5e = 0;
  uint16_t fe70 = 0, fee4w = 0;

  if (f90xCamReadByte(0xFEB0, &feb0)) {
    Serial.print(F("  FEB0=0x"));
    printHexByte(feb0);
    if (feb0 & 0x04) Serial.print(F(" [.2=待过片!]"));
    Serial.println();
  }
  delay(20);
  if (f90xCamReadByte(0xFEB2, &feb2)) {
    Serial.print(F("  FEB2=0x"));
    printHexByte(feb2);
    if (feb2 & 0x04) Serial.print(F(" [.2=过片处理中!]"));
    Serial.println();
  }
  delay(20);
  if (f90xCamReadByte(0xFE40, &fe40)) {
    Serial.print(F("  FE40=0x"));
    printHexByte(fe40);
    if (fe40 == 0x0C) Serial.print(F(" (过片镜像态)"));
    else if (fe40 == 0x0D) Serial.print(F(" (FEBBH忙)"));
    else if (fe40 == 0x0E) Serial.print(F(" (错误/等待态)"));
    Serial.println();
  }
  delay(20);
  if (f90xCamReadByte(0xFED5, &fed5)) {
    Serial.print(F("  FED5=0x"));
    printHexByte(fed5);
    if (fed5 & 0x04) Serial.print(F(" [.2=过片链]"));
    Serial.println();
  }
  delay(20);
  if (f90xCamReadByte(0xFED7, &fed7)) {
    Serial.print(F("  FED7=0x"));
    printHexByte(fed7);
    Serial.println();
  }
  delay(20);
  if (f90xCamReadWord(0xFE70, &fe70)) {
    Serial.print(F("  FE70=0x"));
    printHexByte((uint8_t)(fe70 & 0xFF));
    printHexByte((uint8_t)(fe70 >> 8));
    Serial.println(F(" (延迟函数指针)"));
  }
  delay(20);
  if (f90xCamReadByte(0xFEB5, &feb5)) {
    Serial.print(F("  FEB5=0x"));
    printHexByte(feb5);
    if (feb5) Serial.print(F(" (异步忙)"));
    Serial.println();
  }
  delay(20);
  if (f90xCamReadByte(0xFE47, &fe47)) {
    Serial.print(F("  FE47=0x"));
    printHexByte(fe47);
    if (fe47 & 0x20) Serial.print(F(" [.5→FE40=0E]"));
    Serial.println();
  }
  delay(20);
  if (f90xCamReadByte(0xFE9F, &fe9f)) {
    Serial.print(F("  FE9F=0x"));
    printHexByte(fe9f);
    Serial.println();
  }
  delay(20);
  if (f90xCamReadByte(0xFE5E, &fe5e)) {
    Serial.print(F("  FE5E=0x"));
    printHexByte(fe5e);
    if (fe5e == 0) Serial.print(F(" (倒计时归零→0E)"));
    Serial.println();
  }
  delay(20);
  if (f90xCamReadWord(0xFEE4, &fee4w)) {
    Serial.print(F("  FEE4=0x"));
    printHexByte((uint8_t)(fee4w & 0xFF));
    printHexByte((uint8_t)(fee4w >> 8));
    Serial.println();
  }
}

static bool printFilmEndDiag(const __FlashStringHelper *tag) {
  uint8_t fd14[18];
  uint8_t fed[7];
  uint8_t fe57 = 0, fe24 = 0, fe50 = 0, fe51 = 0;
  uint8_t fed4 = 0, fec5 = 0, fe46 = 0;
  uint8_t febb = 0, fec4 = 0, fe7d = 0;
  uint8_t fd2d = 0;
  uint8_t fd39[10];
  uint8_t n = 0;
  uint8_t fedLen = 0;
  uint8_t fd39Len = 0;
  bool ok = true;

  Serial.print(tag);
  Serial.println(F("FILM/LCD"));

  if (f90xCamReadRam(0xFD14, 18, fd14, sizeof(fd14), &n) && n >= 18) {
    Serial.print(F("  FD14="));
    printHexBuf(fd14, 2);
    Serial.print(F(" FD16(eep186)="));
    printHexBuf(fd14 + 2, 8);
    Serial.print(F(" FD21="));
    printHexByte(fd14[13]);
    Serial.print(F(" FD22="));
    printHexBuf(fd14 + 14, 2);
    Serial.print(F(" FD25=shutter "));
    printHexByte(fd14[17]);
    Serial.println();
  } else {
    ok = false;
    Serial.println(F("  FD14..FD25 read fail"));
    f90xCamPrintLastRx();
  }
  delay(40);

  if (f90xCamReadByte(0xFD2D, &fd2d)) {
    Serial.print(F("  FD2D=0x"));
    printHexByte(fd2d);
    Serial.println(F(" (帧计数相关)"));
  } else ok = false;
  delay(25);

  if (f90xCamReadRam(0xFD39, 10, fd39, sizeof(fd39), &fd39Len) && fd39Len >= 1) {
    Serial.print(F("  FD39="));
    printHexBuf(fd39, fd39Len > 4 ? 4 : fd39Len);
    Serial.println();
  } else ok = false;
  delay(25);

  if (f90xCamReadRam(0xFED0, 7, fed, sizeof(fed), &fedLen) && fedLen >= 7) {
    Serial.print(F("  FED0=0x"));
    printHexByte(fed[0]);
    Serial.print(F(" FED6=0x"));
    printHexByte(fed[6]);
    if (fed[6] & 0x02) Serial.print(F(" [FED6.1]"));
    Serial.println();
  } else {
    ok = false;
    Serial.println(F("  FED0..FED6 read fail"));
  }
  delay(25);

  if (f90xCamReadByte(0xFE57, &fe57)) {
    Serial.print(F("  FE57=0x"));
    printHexByte(fe57);
    Serial.println();
  } else ok = false;
  delay(25);

  if (f90xCamReadByte(0xFE24, &fe24)) {
    Serial.print(F("  FE24=0x"));
    printHexByte(fe24);
    if (fe24 == 0x72) Serial.print(F(" (=114脉冲?)"));
    Serial.println();
  } else ok = false;
  delay(25);

  if (f90xCamReadByte(0xFED4, &fed4)) {
    Serial.print(F("  FED4=0x"));
    printHexByte(fed4);
    if (fed4 & 0x02) Serial.print(F(" [.1=LCD52]"));
    if (fed4 & 0x40) Serial.print(F(" [.6=过片中!]"));
    Serial.println();
  } else ok = false;
  delay(25);

  if (f90xCamReadByte(0xFE7D, &fe7d)) {
    Serial.print(F("  FE7D=0x"));
    printHexByte(fe7d);
    if (fe7d != 0) Serial.print(F(" (半帧计数残留)"));
    Serial.println();
  } else ok = false;
  delay(25);

  if (f90xCamReadByte(0xFEBB, &febb)) {
    Serial.print(F("  FEBBH=0x"));
    printHexByte(febb);
    if (febb & 0x01) Serial.print(F(" [.0=过片忙]"));
    Serial.println();
  } else ok = false;
  delay(25);

  printAdvanceChainExtra();

  if (f90xCamReadByte(0xFEC4, &fec4)) {
    Serial.print(F("  FEC4=0x"));
    printHexByte(fec4);
    Serial.println();
  } else ok = false;
  delay(25);

  if (f90xCamReadByte(0xFEC5, &fec5)) {
    Serial.print(F("  FEC5=0x"));
    printHexByte(fec5);
    if (fec5 & 0x20) Serial.print(F(" [FEC5.5→FE51=5A]"));
    Serial.println();
  } else ok = false;
  delay(25);

  if (f90xCamReadByte(0xFE46, &fe46)) {
    Serial.print(F("  FE46=0x"));
    printHexByte(fe46);
    Serial.println();
  } else ok = false;
  delay(25);

  if (f90xCamReadByte(0xFE50, &fe50) && f90xCamReadByte(0xFE51, &fe51)) {
    Serial.print(F("  LCD FE50=0x"));
    printHexByte(fe50);
    Serial.print(F(" FE51=0x"));
    printHexByte(fe51);
    bool lcdEnd = (fe51 == 0x5A) && (fe50 == 0x52 || fe50 == 0x4D || fe50 == 0x54);
    if (lcdEnd) Serial.print(F(" [LCD End]"));
    Serial.println();
  } else ok = false;

  if (ok && n >= 18) {
    uint8_t fd21 = fd14[13];
    if (fe51 == 0x5A && fe50 == 0x52) {
      Serial.println(F("  => LCD End @第5张: 外刹残留态(FE4E已清)"));
      Serial.println(F("     FE50=52←FED4.1  FE51=5A←FEC5.5  非片尾"));
    } else if (fe51 == 0x5A) {
      Serial.println(F("  => LCD End态 (ROM @1C45/@3CFD)"));
    } else if (fed4 & 0x40) {
      Serial.println(F("  => FED4.6 过片链卡住 — 按 w 或 x"));
    } else if (fe7d != 0) {
      Serial.println(F("  => FE7D 半帧残留 — 按 w 恢复"));
    } else if (febb & 0x07) {
      Serial.println(F("  => FEBBH 过片忙 — 按 w"));
    } else {
      Serial.println(F("  => 无 LCD End；若仍不过片看 FEB2/FE40"));
    }
    if (fd21 >= 0x01 && fd21 <= 0x28) {
      Serial.print(F("  => FD21=第"));
      Serial.print((int)fd21 - 1);
      Serial.println(F(" 张附近"));
    }
  }

  return ok;
}

static void printRamDiag(const __FlashStringHelper *tag) {
  gCamBusy = true;

  if (!f90xCamEnsureSession(true)) {
    Serial.println(F("RAM bootstrap fail — press b"));
    gCamBusy = false;
    return;
  }
  delay(100);

  Serial.print(tag);
  printWindErrorDiag();
  printFilmEndDiag(F(""));

  gCamBusy = false;
}

static void printUsbHelp() {
  Serial.println(F("--- USB commands (115200, Uno USB) ---"));
  Serial.println(F("  r  read wind-error + film-end RAM"));
  Serial.println(F("  p  read film/LCD (FD21 FE50/FE51 FD2D)"));
  Serial.println(F("  c  clear wind-error (FE4E/FEE1/FEE4)"));
  Serial.println(F("  x  clear LCD End + resume (LATCH 成功自动松刹)"));
  Serial.println(F("  w  resume advance (FEB0/FEB2/FE40 chain)"));
  Serial.println(F("  b  bootstrap camera serial"));
  Serial.println(F("  e  end serial session"));
  Serial.println(F("  l  force IDLE + release brake"));
  Serial.println(F("  h  this help"));
}

static bool lcdEndLooksCleared(uint8_t fe50, uint8_t fe51) {
  return fe51 != 0x5A && fe50 != 0x52;
}

static bool fe4eIsLoadMode(uint8_t fe4e) {
  return fe4e == 0x01 || fe4e == 0x02 || fe4e == 0x04 || fe4e == 0x21;
}

static void updateLoadArmBlock() {
  if (gCamBusy || !f90xCamIsReady()) return;
  if (gSt != ST_IDLE && gSt != ST_LATCH) return;

  uint32_t now = millis();
  if (gLastLoadPollMs != 0 && now - gLastLoadPollMs < LOAD_BLOCK_POLL_MS) return;

  gLastLoadPollMs = now;
  gCamBusy = true;
  uint8_t fe4e = 0;
  bool wasBlocked = gBlockArmForLoad;
  if (f90xCamReadByte(0xFE4E, &fe4e)) {
    gBlockArmForLoad = fe4eIsLoadMode(fe4e);
    if (gBlockArmForLoad && !wasBlocked) {
      Serial.print(F("ARM block load FE4E=0x"));
      printHexByte(fe4e);
      Serial.println();
    } else if (!gBlockArmForLoad && wasBlocked) {
      Serial.println(F("ARM load block off"));
    }
  }
  gCamBusy = false;
}

static void releaseBrakeToIdle(const __FlashStringHelper *tag) {
  brakeOff();
  gFromLatch = false;
  gSt = ST_IDLE;
  gArmN = 0;
  gCnt = 0;
  gBrakeClrPending = false;
  gBrakeClrDone = false;
  gBrakeClrVerified = false;
  gLatchClrFailN = 0;
  gLatchQuietUntilMs = 0;
  gLastEndPollMs = millis() + LATCH_END_FAIL_MS;
  Serial.print(tag);
  Serial.println(F(" auto brake off"));
}

static void releaseBrakeIfLatched(const __FlashStringHelper *tag) {
  if (gSt != ST_LATCH) return;
  releaseBrakeToIdle(tag);
}

static bool clearEndAggressive(const __FlashStringHelper *tag) {
  for (uint8_t n = 0; n < 3; n++) {
    if (f90xCamClearEndStateFast()) {
      Serial.print(tag);
      Serial.println(F(" fast ok"));
      return true;
    }
    if (f90xCamClearEndStateBrake()) {
      Serial.print(tag);
      Serial.println(F(" med ok"));
      return true;
    }
    if (f90xCamClearEndState()) {
      Serial.print(tag);
      Serial.println(F(" full ok"));
      return true;
    }
    delay(40);
  }
  return false;
}

// 手动清 End：握手 → 读 FE4E → 三档重试写零 → 读回验证
static bool manualClearEnd() {
  gCamBusy = true;

  if (!f90xCamEnsureSession(true)) {
    Serial.println(F("MANUAL bootstrap fail — try b"));
    gCamBusy = false;
    return false;
  }
  delay(100);

  uint8_t fe4e = 0xFF;
  if (f90xCamReadByte(0xFE4E, &fe4e)) {
    Serial.print(F("MANUAL before FE4E=0x"));
    printHexByte(fe4e);
    Serial.println();
  } else {
    Serial.println(F("MANUAL read fail — blind CLR"));
    f90xCamPrintLastRx();
  }

  bool ok = clearEndAggressive(F("MANUAL CLR"));
  if (!ok) ok = f90xCamClearEndStateRetry(3);

  if (f90xCamReadByte(0xFE4E, &fe4e)) {
    Serial.print(F("MANUAL after FE4E=0x"));
    printHexByte(fe4e);
    if (fe4e == 0) {
      Serial.println(F(" OK"));
      f90xCamEndSession(false);
      gEndProbeDone = false;
    } else {
      Serial.println(F(" still error"));
    }
  } else if (ok) {
    Serial.println(F("MANUAL CLR sent (unverified)"));
  } else {
    Serial.println(F("MANUAL CLR FAIL — retry c or b then c"));
    f90xCamPrintLastRx();
  }

  gCamBusy = false;
  return ok;
}

// 仅恢复卷片链（LCD 已清但电机不动时用）
static bool manualResumeAdvance() {
  gCamBusy = true;

  if (!f90xCamEnsureSession(true)) {
    Serial.println(F("RESUME bootstrap fail — try b"));
    gCamBusy = false;
    return false;
  }
  delay(100);

  uint8_t fed4 = 0, fe7d = 0, feb2 = 0, fe40 = 0;
  if (f90xCamReadByte(0xFED4, &fed4) && f90xCamReadByte(0xFE7D, &fe7d)) {
    Serial.print(F("RESUME before FED4=0x"));
    printHexByte(fed4);
    Serial.print(F(" FE7D=0x"));
    printHexByte(fe7d);
    Serial.println();
  }

  bool ok = false;
  for (uint8_t n = 0; n < 3 && !ok; n++) {
    ok = f90xCamResumeAdvanceState();
    delay(60);
  }

  bool gotAfter = f90xCamReadByte(0xFED4, &fed4) && f90xCamReadByte(0xFE7D, &fe7d);
  (void)f90xCamReadByte(0xFEB2, &feb2);
  (void)f90xCamReadByte(0xFE40, &fe40);

  if (gotAfter) {
    Serial.print(F("RESUME after  FED4=0x"));
    printHexByte(fed4);
    Serial.print(F(" FE7D=0x"));
    printHexByte(fe7d);
    Serial.print(F(" FEB2=0x"));
    printHexByte(feb2);
    Serial.print(F(" FE40=0x"));
    printHexByte(fe40);
    Serial.println();
    if (ok) {
      Serial.println(F(" OK —按 l 松刹后试快门过片"));
      f90xCamEndSession(false);
      gEndProbeDone = false;
    } else {
      Serial.println(F(" partial — 按 r 看 FEB2/FE40/FEBBH，再试 w 或关机"));
      if (!ok) f90xCamPrintLastRx();
    }
  } else if (ok) {
    Serial.println(F("RESUME sent (unverified)"));
  } else {
    Serial.println(F("RESUME FAIL — 按 r 或 b 后重试"));
    f90xCamPrintLastRx();
  }

  gCamBusy = false;
  return ok;
}

// 清 LCD End（FE4E=0 仍显示 End）：FEC5.5/FED4.1/FE50/FE51
static bool manualClearLcdEnd() {
  gCamBusy = true;

  if (!f90xCamEnsureSession(true)) {
    Serial.println(F("LCD CLR bootstrap fail — try b"));
    gCamBusy = false;
    return false;
  }
  delay(100);

  uint8_t fe50 = 0, fe51 = 0;
  if (f90xCamReadByte(0xFE50, &fe50) && f90xCamReadByte(0xFE51, &fe51)) {
    Serial.print(F("LCD before FE50=0x"));
    printHexByte(fe50);
    Serial.print(F(" FE51=0x"));
    printHexByte(fe51);
    Serial.println();
  }

  bool ok = false;
  bool lcdOk = false;
  bool chainOk = false;
  for (uint8_t n = 0; n < 3 && !ok; n++) {
    ok = f90xCamClearLcdEndState() && f90xCamResumeAdvanceState();
    delay(60);
  }

  if (f90xCamReadByte(0xFE50, &fe50) && f90xCamReadByte(0xFE51, &fe51)) {
    lcdOk = lcdEndLooksCleared(fe50, fe51);
    chainOk = f90xCamAdvanceChainLooksIdle();
    Serial.print(F("LCD after  FE50=0x"));
    printHexByte(fe50);
    Serial.print(F(" FE51=0x"));
    printHexByte(fe51);
    if (lcdOk && chainOk) {
      Serial.println(F(" OK"));
      gEndProbeDone = false;
      gLatchClrFailN = 0;
#if AUTO_RELEASE_BRAKE_ON_X
      releaseBrakeIfLatched(F("LCD CLR"));
#endif
    } else if (lcdOk) {
      Serial.println(F(" LCD ok chain busy —试 w 或再 x"));
      gEndProbeDone = false;
      pollRecoverAutoRelease(true);
    } else {
      Serial.println(F(" still End — retry x"));
    }
  } else if (ok) {
    Serial.println(F("LCD CLR sent (unverified)"));
  } else {
    Serial.println(F("LCD CLR FAIL"));
    f90xCamPrintLastRx();
  }

  gCamBusy = false;
  return ok;
}

static void probeCamEndOnce() {
  if (gEndProbeDone || gCamBusy || !f90xCamIsReady()) return;
  if (gSt != ST_IDLE && gSt != ST_LATCH) return;

  gCamBusy = true;
  uint8_t fe4e = 0, fe50 = 0, fe51 = 0;
  bool gotFe4e = f90xCamReadByte(0xFE4E, &fe4e);
  delay(20);
  bool gotLcd = f90xCamReadByte(0xFE50, &fe50) && f90xCamReadByte(0xFE51, &fe51);
  delay(20);

  if (gotFe4e && fe4e != 0) {
    Serial.print(F("CAM wind-error FE4E=0x"));
    printHexByte(fe4e);
    Serial.println(F(" — press c"));
  } else if (gotLcd && fe51 == 0x5A &&
             (fe50 == 0x52 || fe50 == 0x4D || fe50 == 0x54)) {
    Serial.print(F("CAM LCD-End FE50=0x"));
    printHexByte(fe50);
    Serial.print(F(" FE51=0x"));
    printHexByte(fe51);
    Serial.println(F(" — press x (c无效)"));
  }
  gEndProbeDone = true;
  gCamBusy = false;
}

static bool tryBrakeFullClear() {
  uint32_t t0 = millis();
  bool verified = false;
  if (!f90xCamBrakeFullRecover(&verified)) {
    Serial.print(F("BRAKE full fail "));
    Serial.print(millis() - t0);
    Serial.println(F("ms"));
    return false;
  }
  Serial.print(F("BRAKE full "));
  Serial.print(millis() - t0);
  Serial.println(F("ms"));
  if (verified) {
    Serial.println(F("BRAKE verify ok"));
    gBrakeClrVerified = true;
    gLatchClrFailN = 0;
    gEndProbeDone = false;
  } else {
    Serial.println(F("BRAKE partial — x/w if no wind"));
  }
  return true;
}

static void pollRecoverAutoRelease(bool verified) {
#if AUTO_RELEASE_BRAKE_ON_X
  if (verified) releaseBrakeIfLatched(F("LATCH CLR"));
#else
  (void)verified;
#endif
}

static void tryIdlePreboot() {
  if (gCamBusy || f90xCamIsReady()) return;
  if (gSt != ST_IDLE && gSt != ST_LATCH) return;
  if (gSt == ST_LATCH && millis() < gLatchQuietUntilMs) return;

  uint32_t now = millis();
  if (gLastPrebootMs != 0 && now - gLastPrebootMs < PREBOOT_RETRY_MS) return;

  gLastPrebootMs = now;
  gCamBusy = true;
  if (f90xCamBootstrap(false)) {
    Serial.println(F("PREBOOT ok"));
    gEndProbeDone = false;
  } else {
    Serial.println(F("PREBOOT fail — press b"));
    gLastPrebootMs = now - PREBOOT_RETRY_MS + PREBOOT_FAIL_MS;
  }
  gCamBusy = false;
}

static void pollEndAndClear() {
  if (gSt != ST_LATCH) return;

  gCamBusy = true;
  uint32_t nextPollMs = LATCH_END_POLL_MS;

  if (gBrakeClrVerified) {
    if (f90xCamIsReady()) {
      uint8_t fe51 = 0, fe50 = 0;
      if (f90xCamReadByte(0xFE51, &fe51) &&
          f90xCamReadByte(0xFE50, &fe50) &&
          lcdEndLooksCleared(fe50, fe51) &&
          f90xCamAdvanceChainLooksIdle()) {
        gLatchClrFailN = 0;
        nextPollMs = 30000;
#if AUTO_RELEASE_BRAKE_ON_X
        releaseBrakeToIdle(F("LATCH ok"));
#endif
        goto done;
      }
      gBrakeClrVerified = false;
      Serial.println(F("LATCH re-check: need CLR again"));
    }
  }

  if (!f90xCamIsReady()) {
    if (!f90xCamBootstrap(false)) {
      Serial.println(F("END poll bootstrap fail"));
      nextPollMs = LATCH_END_FAIL_MS;
      goto done;
    }
  }
  delay(50);

  {
    uint8_t fe4e = 0;
    bool readOk = f90xCamReadByte(0xFE4E, &fe4e);
    bool needRecover = false;

    if (readOk && fe4e == 0) {
      uint8_t fe51 = 0, fe50 = 0;
      bool gotLcd = f90xCamReadByte(0xFE51, &fe51) &&
                    f90xCamReadByte(0xFE50, &fe50);
      if (gotLcd && fe51 == 0x5A &&
          (fe50 == 0x52 || fe50 == 0x4D || fe50 == 0x54)) {
        needRecover = true;
      } else if (!f90xCamAdvanceChainLooksIdle()) {
        needRecover = true;
      } else {
        gLatchClrFailN = 0;
        nextPollMs = 10000;
        goto done;
      }
    } else if (readOk) {
      Serial.print(F("END det FE4E=0x"));
      printHexByte(fe4e);
      Serial.println();
      needRecover = true;
    } else {
      Serial.println(F("END read fail — blind CLR"));
      needRecover = true;
    }

    if (needRecover) {
      bool verified = false;
      if (f90xCamBrakeFullRecover(&verified)) {
        gLatchClrFailN = 0;
        Serial.println(verified ? F("LATCH CLR verify ok") : F("LATCH CLR partial"));
        if (verified) {
          gBrakeClrVerified = true;
          pollRecoverAutoRelease(true);
        } else {
          uint8_t fe51 = 0, fe50 = 0;
          if (f90xCamReadByte(0xFE50, &fe50) &&
              f90xCamReadByte(0xFE51, &fe51) &&
              lcdEndLooksCleared(fe50, fe51)) {
            Serial.println(F("LATCH LCD ok — auto brake off, try w if stuck"));
            pollRecoverAutoRelease(true);
          }
        }
        gEndProbeDone = false;
      } else {
        gLatchClrFailN++;
        Serial.print(F("LATCH CLR FAIL n="));
        Serial.println(gLatchClrFailN);
        nextPollMs = LATCH_END_FAIL_MS;
        if (gLatchClrFailN >= LATCH_STUCK_FAIL_N) {
          Serial.println(F("STUCK: force brake off → IDLE (try w/x)"));
          releaseBrakeIfLatched(F("STUCK"));
          gLatchClrFailN = 0;
        }
      }
    }
  }

done:
  gLastEndPollMs = millis() + nextPollMs;
  gCamBusy = false;
}

static void handleUsbCommand(char c) {
  switch (c) {
    case 'c':
    case 'C':
      manualClearEnd();
      return;
    case 'x':
    case 'X':
      manualClearLcdEnd();
      return;
    case 'w':
    case 'W':
      manualResumeAdvance();
      return;
  }

  if (gCamBusy) return;

  switch (c) {
    case 'r':
    case 'R':
      printRamDiag(F("MANUAL "));
      break;
    case 'p':
    case 'P':
      gCamBusy = true;
      if (!f90xCamEnsureSession(true)) {
        Serial.println(F("FILM bootstrap fail — press b"));
      } else {
        delay(100);
        printFilmEndDiag(F("MANUAL "));
      }
      gCamBusy = false;
      break;
    case 'h':
    case 'H':
    case '?':
      printUsbHelp();
      break;
    case 'b':
    case 'B':
      gCamBusy = true;
      gLastPrebootMs = millis();
      if (f90xCamBootstrap(true))
        Serial.println(F("bootstrap OK"));
      else
        Serial.println(F("bootstrap FAIL"));
      gCamBusy = false;
      break;
    case 'e':
    case 'E':
      gCamBusy = true;
      f90xCamEndSession(true);
      gLastPrebootMs = 0;
      gEndProbeDone = false;
      Serial.println(F("session end"));
      gCamBusy = false;
      break;
    case 'l':
    case 'L':
      releaseBrakeToIdle(F("force"));
      break;
    default:
      break;
  }
}

static void brakeOn() {
  pinMode(PIN_IN1, OUTPUT);
  pinMode(PIN_IN2, OUTPUT);
#if BRAKE_OPEN_DRAIN
  digitalWrite(PIN_IN1, LOW);
  digitalWrite(PIN_IN2, LOW);
#else
  digitalWrite(PIN_IN1, HIGH);
  digitalWrite(PIN_IN2, HIGH);
#endif
}

static void brakeOff() {
#if !BRAKE_OPEN_DRAIN
  digitalWrite(PIN_IN1, LOW);
  digitalWrite(PIN_IN2, LOW);
#endif
  pinMode(PIN_IN1, INPUT);
  pinMode(PIN_IN2, INPUT);
}

static void intpListenOn() {
  pinMode(PIN_INTP, INPUT);
  attachInterrupt(digitalPinToInterrupt(PIN_INTP), onIntp, RISING);
}

static void startCooldown() {
  gCoolUntilMs = millis() + COOLDOWN_MS;
}

static bool canArm() {
  return millis() >= gCoolUntilMs;
}

static void enterLatch() {
  gSt = ST_LATCH;
  gLatchQuietUntilMs = millis() + LATCH_SERIAL_DEFER_MS;
  gLastEndPollMs = millis() + LATCH_SERIAL_DEFER_MS;
}

static void endFrame() {
  Serial.print(F("OK brake="));
  Serial.print(gCntAtBrake);
  Serial.print(F(" hold_ms="));
  Serial.println(millis() - gHoldStartMs);
  gCnt = 0;
  gArmN = 0;
  startCooldown();
#if AUTO_RELEASE_BRAKE_ON_X
  if (gBrakeClrVerified) {
    releaseBrakeToIdle(F("BRAKE"));
    return;
  }
#endif
  Serial.println(F("LATCH"));
  enterLatch();
}

static void discardBurst() {
  if (gFromLatch) {
    gFromLatch = false;
    gArmN = 0;
    brakeOn();
    gSt = ST_LATCH;
    startCooldown();
    return;
  }
  brakeOff();
  gSt = ST_IDLE;
  gCnt = 0;
  gArmN = 0;
  startCooldown();
}

void onIntp() {
  uint32_t t = micros();
  gLastIntpMs = millis();

  if (gSt == ST_IDLE || gSt == ST_LATCH) {
    if (!canArm()) return;
    if (gBlockArmForLoad) return;
    gFromLatch = (gSt == ST_LATCH);
    gSt = ST_ARM;
    gArmN = 1;
    gArmUs = t;
    return;
  }

  if (gSt == ST_ARM) {
    gArmN++;
    uint8_t needArm = gFromLatch ? ARM_PULSES_LATCH : ARM_PULSES;
    if (gArmN >= needArm &&
        (t - gArmUs) < (uint32_t)ARM_WINDOW_MS * 1000UL) {
      brakeOff();
      gFromLatch = false;
      gSt = ST_RUN;
      gCnt = gArmN;
      gBrakeClrPending = false;
      gBrakeClrDone = false;
      gBrakeClrVerified = false;
      Serial.println(F("RUN"));
    }
    return;
  }

  if (gSt == ST_RUN) {
    gCnt++;
    if (gCnt >= BRAKE_AT) {
      gSt = ST_HOLD;
      gHoldStartMs = millis();
      gCntAtBrake = gCnt;
      brakeOn();
      gBrakeClrPending = true;
      gBrakeClrDone = false;
      gBrakeClrVerified = false;
      Serial.print(F("BRAKE@"));
      Serial.println(gCnt);
    }
    return;
  }

  if (gSt == ST_HOLD) {
    gCnt++;
  }
}

void setup() {
  pinMode(PIN_INTP, INPUT);
  brakeOff();
  intpListenOn();
  Serial.begin(115200);
  gBootMs = millis();
  f90xCamForceReset();
  Serial.print(F("F90X "));
  Serial.println(FW_VERSION);
  Serial.print(F("BRAKE_AT="));
  Serial.println(BRAKE_AT);
  Serial.println(F("USB: r/p  x  w  c  b  e  l  h"));
}

void loop() {
  uint32_t now = millis();

  while (Serial.available()) {
    handleUsbCommand((char)Serial.read());
  }

  if (gSt == ST_IDLE || gSt == ST_LATCH) {
    tryIdlePreboot();
    updateLoadArmBlock();
    probeCamEndOnce();
  }

  if (gSt == ST_BOOT) {
    brakeOff();
    if (now - gBootMs >= BOOT_MS) {
      gSt = ST_IDLE;
      Serial.println(F("READY"));
    }
    return;
  }

  if (gSt == ST_ARM && now - gLastIntpMs >= CONFIRM_MS) {
    discardBurst();
    return;
  }

  if (gSt == ST_HOLD) {
    if (gBrakeClrPending && !gBrakeClrDone && !gCamBusy &&
        now - gHoldStartMs >= BRAKE_CLR_SETTLE_MS) {
      gCamBusy = true;
      (void)tryBrakeFullClear();
      gBrakeClrDone = true;
      gBrakeClrPending = false;
      gBrakeClrDoneMs = millis();
      gCamBusy = false;
    }

    if (!gBrakeClrDone) return;
    if (now - gBrakeClrDoneMs < POST_CLR_GAP_MS) return;
    endFrame();
    return;
  }

  if (gSt == ST_LATCH) {
    if (!gCamBusy && now >= gLatchQuietUntilMs && now >= gLastEndPollMs) {
      pollEndAndClear();
    }
  }
}

仓库链接：kuixiaoran/f90x-film-leader-customizer

发布视频：

写在前面：

尼康F时代胶片相机，从Nikon F90/N90开始使用10pin接口，这个接口作为尼康机身附件和电子通讯接口，一直延续到Z时代。

在胶片机时代，由于机身电子化程度有限，用户没有办法在机身侧设置全部自定义选项。

但是有10pin接口，我们可以通过电脑自定义设置机身选项和读取机身存储的拍摄信息。

尼康也为Nikon F90/N90系列、Nikon F5、Nikon F100各自开发了对应软件进行自定义设置和管理。

F6则没有官方软件，因为F6时代机身电子化程度已经极高，日常选项均可以通过机身自定义。

但是可惜的是，尼康的F系列电子胶片机，回卷留片头功能上除了F6，都需要回到尼康售后服务站进行设置。

时光荏苒，你现在拿这些胶片机去尼康，售后都不一定认得全。

因此留片头功能似乎成了遥远的传说。

翻看尼康售后服务手册，不难发现这类功能均是通过机内eeprom进行管理，因此我们只需要找到读写eeprom的方式即可。

拆下来eeprom进行读写是可行的操作，但是拆机和焊接对于这些几十岁的柔性fpc电路板来说，风险着实不小。

既然官方售后软件通过10pin接口进行通讯，那么我们是不是也能找到路径？

在Nikon F90X/N90S上，我们取得了一些突破，通过逆向MCU的启动逻辑，我们知道了如何通过10pin，操作寄存器对eeprom进行读写。

得益于如今不断发展的AI coding，我们可以很快将其软件化，虽然这真的很小众，也没有商业价值，但整个过程真是一种又老又新的奇妙体验。

关于软件：

1. 读取 EEPROM 镜像（Dump）

连接相机串口后，可一次性读取 512 字节 EEPROM 数据，并在本地保存为镜像文件。
建议每次修改前先 Dump 并备份 .bin 文件——这是日后恢复或对比的「保险单」。

2. 调整留片头长度（MODIFY）

软件针对 地址 0x169 的留片头参数进行写入。数值为十进制 6～31，与物理留片头大致对应关系如下：

数值越小，留片头越长；越大则越短。
界面上可通过 拖动胶片 的方式直观设定，软件会自动限制在合法范围内，避免写入越界数值。

写入时软件会按协议完成数据写入，并 更新校验和（0x017F），降低因校验不匹配导致相机异常的风险。

PS：经过测试，31（DEC）会比5mm略长一些，不过为了稳定性考虑，如果您自己重新编译该软件，不建议写入数值大于33（DEC）。

3. 高级功能

面向有经验的用户，「高级」面板提供：

• HxD 风格十六进制镜像：查看完整 EEPROM 布局，0x017F 校验和位置会高亮显示
• 校验和状态：当前值、期望值、是否一致
• 再次 Dump：只刷新内存镜像，不弹出保存对话框
• 仅写 0x017F：在 MODIFY 部分失败、但数据已正确写入时，可单独补写校验和

4. 多语言日志

日志与后端错误提示支持 中文 / English / 日本語 切换，便于不同用户阅读；不影响串口协议与写入逻辑。

5. 界面与体验

软件采用 Wails 桌面框架 + React 界面，配合 Motion 动画，还原「胶片、后盖、串口连接」等操作场景，让流程更清晰：
开场连接 → 工作区 Dump / 修改 → 底部日志与高级面板。

注意事项与免责声明（请务必阅读）

操作风险

1. EEPROM 写入具有不可逆性
   错误写入可能导致相机行为异常。务必在修改前 Dump 并保存备份。
2. 仅修改受支持的参数
   常规 MODIFY 流程 只允许写入 0x169（留片头，DEC 6～31）。请勿随意使用高级功能修改其他地址，除非你完全理解后果。
3. 串口连接要稳定
   写入过程中请勿拔线、休眠或运行可能占用串口的其他软件。若出现 FEB 超时，请按日志提示处理：可尝试重新连接、重新 Dump，或在确认数据已正确写入后 仅写校验和。
4. 校验和很重要
   留片头数据写入后，应确保 0x017F 校验和 与算法一致。软件会在成功 MODIFY 流程中自动处理；若中断，请使用高级面板的「仅写 0x017F」或按日志指引恢复。
5. 非官方工具
   本软件 与相机制造商无关，属于爱好者工具。使用即表示你理解并自行承担风险。建议在非关键任务上先小规模验证，再用于日常拍摄配置。

使用建议

• 第一次使用前：通读日志输出，确认 Dump 成功、镜像中 0x169 与预期一致
• 每次修改前：保存一份带日期的 .bin 备份
• 修改后：可在相机上实际装片、过片，确认留片头是否符合预期
• 遇到异常：保留完整日志，便于排查是连接问题、协议超时还是校验问题

写在最后

Nikon F90X 的留片头调节，本质上是在 几字节 EEPROM 数据 与 实际装片

如果你也在折腾 F90X/N90S的胶片回卷与留片头，欢迎交流使用反馈与改进建议。
使用前请再次确认：已备份、已理解风险、已在安全环境下测试。