# RP2040 注入器嗅探数据 -> I2C 协议解码
# 用法: python i2c_sniff_decode.py [COM口] [采集ms, 默认700]
# 帧格式: 固件 'c' 命令回吐 "C <t_us> <val>" 行, val bit0=SDA bit1=SCL
import serial, sys, time

PORT = sys.argv[1] if len(sys.argv) > 1 else 'COM9'
MS = int(sys.argv[2]) if len(sys.argv) > 2 else 700

KNOWN_REGS = {0x44: 'SYS_STATUS', 0x6E: 'TTL_8B_CFG', 0xFF: 'BANK'}

s = serial.Serial(PORT, timeout=1)
time.sleep(0.3)
s.reset_input_buffer()
s.write(b's\n')
time.sleep(0.3)
print(s.read(200).decode('utf-8', 'replace').strip())
s.write(('c %d\n' % MS).encode())

edges = []
t_deadline = time.time() + MS / 1000 + 60
while time.time() < t_deadline:
    ln = s.readline().decode('ascii', 'replace').strip()
    if ln == 'C.':
        break
    if ln.startswith('C '):
        try:
            a, b = ln[2:].split()
            edges.append((int(a), int(b)))
        except ValueError:
            pass
    elif ln.startswith('='):
        print(ln)
s.close()
print('edges:', len(edges))

# ---------------- I2C 解码 ----------------
trans, cur, bits = [], None, []
psda = pscl = None

def flush_byte():
    global bits
    if cur is not None and len(bits) == 8:
        cur['bytes'].append(int(''.join(str(x) for x in bits), 2))
        bits = []

for t, v in edges:
    sda, scl = v & 1, (v >> 1) & 1
    if pscl is not None:
        if scl == 1 and pscl == 1:                    # SCL 高电平期间 SDA 变化
            if psda == 1 and sda == 0:                # START / repeated START
                if cur is not None:
                    cur['t1'] = t
                    cur['inc'] = bool(bits)
                    trans.append(cur)
                cur = {'t0': t, 'bytes': [], 'acks': [], 'inc': False}
                bits = []
            elif psda == 0 and sda == 1:              # STOP
                if cur is not None:
                    cur['t1'] = t
                    cur['inc'] = bool(bits)
                    trans.append(cur)
                    cur = None
                bits = []
        elif scl == 1 and pscl == 0:                  # SCL 上升沿采样
            if cur is not None:
                bits.append(sda)
                if len(bits) == 8:
                    cur['bytes'].append(int(''.join(str(x) for x in bits), 2))
                    bits = []
                elif len(bits) == 9:
                    cur['acks'].append(sda)           # 0=ACK
                    bits = []
    psda, pscl = sda, scl
if cur is not None:
    cur['t1'] = edges[-1][0] if edges else 0
    cur['inc'] = bool(bits)
    trans.append(cur)

# ---------------- 打印 ----------------
bank = None
print(f'\n解码出 {len(trans)} 个事务:')
for k, tr in enumerate(trans):
    d = tr['bytes']
    if not d:
        print('  [%2d] t=%dus  <空/片段>' % (k, tr['t0']))
        continue
    addr7, rw = d[0] >> 1, 'R' if d[0] & 1 else 'W'
    acks = tr['acks']
    body = d[1:]
    ann = []
    if addr7 == 0x32 and rw == 'W' and body:
        if body[0] == 0xFF and len(body) >= 2:
            bank = body[1]
            ann.append('bank=%02X' % bank)
            body = body[2:]
        if body:
            r = body[0]
            note = KNOWN_REGS.get(r, '')
            if r == 0xFF:
                bank = body[1] if len(body) > 1 else bank
                note = 'bank=%02X' % bank if len(body) > 1 else note
            ann.append(('[%02X%02X] %s' % (bank or 0, r, note)) if note else '[%02X?%02X]' % (bank or 0, r))
    ackstr = ''.join('A' if a == 0 else 'N' for a in acks[1:]) if len(acks) > 1 else ''
    flag = ' <未收尾>' if tr.get('inc') else ''
    print('  [%2d] t=%7dus  0x%02X %s: %-30s ACK:%s%s'
          % (k, tr['t0'], addr7, rw,
             ' '.join('%02X' % x for x in d[1:12]) + (' …' if len(d) > 12 else ''),
             ackstr[:16], flag))

# 轮询周期统计(相邻事务起始间隔的主值)
if len(trans) > 3:
    gaps = [b['t0'] - a['t0'] for a, b in zip(trans, trans[1:])]
    gaps = [g for g in gaps if 1000 < g < 5000000]
    if gaps:
        gaps.sort()
        print('\n相邻事务间隔(us): 中位=%d 最小=%d 最大=%d'
              % (gaps[len(gaps) // 2], gaps[0], gaps[-1]))