# Linux (i2c-tools)
i2cdetect -y 1           # 扫描 /dev/i2c-1
i2cdetect -r 1 0x03 0x77 # 指定范围

Python:

from smbus2 import SMBus
bus = SMBus(1)
for addr in range(0x03, 0x78):
    try:
        bus.read_byte(addr)
        print(f"Found: 0x{addr:02X}")
    except OSError:
        pass

FTDI:

from pyftdi.i2c import I2cController
i2c = I2cController()
i2c.configure('ftdi://ftdi:232h/1')
for addr in range(0x03, 0x78):
    try:
        dev = i2c.get_port(addr)
        dev.read(1)
        print(f"Found: 0x{addr:02X}")
    except Exception:
        pass

2. 读寄存器

# smbus2
bus.read_byte_data(dev_addr, reg_addr)
bus.read_i2c_block_data(dev_addr, reg_addr, length)

# pyftdi
port = i2c.get_port(dev_addr)
port.write([reg_addr])
data = port.read(length)

3. 写寄存器

bus.write_byte_data(dev_addr, reg_addr, value)
# pyftdi
port.write([reg_addr, value])

SPI 工作流

1. 收发数据

# Linux spidev
spidev_test -D /dev/spidev0.0 -s 1000000 -p "\x9F\x00\x00\x00"

Python:

import spidev
spi = spidev.SpiDev()
spi.open(0, 0)
spi.max_speed_hz = 1000000
spi.mode = 0
# 读取 JEDEC ID
resp = spi.xfer2([0x9F, 0x00, 0x00, 0x00])

FTDI:

from pyftdi.spi import SpiController
spi = SpiController()
spi.configure('ftdi://ftdi:232h/1')
port = spi.get_port(cs=0, freq=1E6, mode=0)
data = port.exchange([0x9F, 0x00, 0x00, 0x00])

2. SPI Flash 操作

读 JEDEC ID: 0x9F
读状态寄存器: 0x05
写使能: 0x06
读数据: 0x03 + 3B addr
页编程: 0x02 + 3B addr + data
扇区擦除: 0x20 + 3B addr

常用设备地址速查

设备	I2C 地址	常见用途
EEPROM (24Cxx)	0x50-0x57	存储
温度传感器 (LM75)	0x48-0x4F	测温
RTC (DS3231)	0x68	实时时钟
OLED (SSD1306)	0x3C/0x3D	显示屏
IMU (MPU6050)	0x68/0x69	姿态传感器
GPIO (PCA9555)	0x20-0x27	IO 扩展

脚本

scripts/i2c_scan.py — 多适配器 I2C 总线扫描
scripts/i2c_reg_rw.py — I2C 寄存器批量读写
scripts/spi_flash_tool.py — SPI Flash 读写擦除

适配器	I2C	SPI	Python 库
FTDI (FT232H/FT2232H)	✓	✓	`pyftdi`
CH341	✓	✓	`ch341`
Aardvark	✓	✓	`aardvark`
树莓派	✓	✓	`smbus2` / `spidev`
Linux /dev/i2c-N	✓	✗	`smbus2`
MCU 桥接器	✓	✓	自定义串口协议

i2c-spi-tools

I2C / SPI Tools

支持的适配器

I2C 工作流

1. 扫描总线