硬件背景
I2C
如下图所示，简单来说I2C是一种同步、串行、多主从的通信总线，由时钟线（SCL）与数据线（SDA）组成。在总线上的设备由一个唯一的地址识别，并且可以作为发送器或接收器运行，具体取决于设备的功能。
图1.1 I2C总线结构图
OpenSBI v1.2.2
\ | /
- RT - Thread Smart Operating System
/ | \ 5.2.2 build Oct 25 2025 01:21:25
2006 - 2024 Copyright by RT-Thread team
lwIP-2.1.2 initialized!
[I/drv_i2c] i2c0 clock=100000000Hz
[I/drv_i2c] i2c0 slave address=0x50
[I/drv_i2c] slave-eeprom size: 256
[I/sal.skt] Socket Abstraction Layer initialize success.
[I/utest] utest is initialize success.
[I/utest] total utest testcase num: (4)
[I/drivers.serial] Using /dev/ttyS0 as default console
tmpfs mounted on /dev/shm success!
file system initialization done!
Press any key to stop init process startup ... 3
Press any key to stop init process startup ... 2
Press any key to stop init process startup ... 1
Starting init ...
Hello RISC-V
msh />cat /dev/i2c-slv-eeprom
msh />echo "0123" /dev/i2c-slv-eeprom
msh />cat /dev/i2c-slv-eeprom
0123
msh />utest_run bsp.k230.drivers.i2c
[I/utest] [] [ utest ] loop 1/1
[I/utest] [] [ utest ] started
[I/utest] [----------] [ testcase ] (bsp.k230.drivers.i2c) started
[I/utest] i2c bus(pin: 48, 49) is idle, init i2c bus pin
[I/utest] This is a i2c test case.
[I/utest] [==========] utest unit name: (test_i2c0_master_slave)
[I/utest] slave buffer data:
[I/utest] 0x34
[I/utest] 0x35
[I/utest] 0x36
[I/utest] 0x37
[I/utest] 0x00
[I/utest] 0x00
[I/utest] 0x00
[I/utest] 0x00
[I/utest] 0x00
[I/utest] 0x00
[I/utest] 0x00
[I/utest] 0x00
[I/utest] 0x00
[I/utest] 0x00
[I/utest] 0x00
[I/utest] 0x00
[I/utest] [ PASSED ] [ result ] testcase (bsp.k230.drivers.i2c)
[I/utest] i2c bus pin deinit.
[I/utest] [----------] [ testcase ] (bsp.k230.drivers.i2c) finished
[I/utest] [] [ utest ] 1 tests from 4 testcase ran.
[I/utest] [ PASSED ] [ result ] 1 tests.
[I/utest] [] [ utest ] finished
msh />cat /dev/i2c-slv-eeprom
4567
msh />
OpenSBI v1.2.2
\ | /
- RT - Thread Smart Operating System
/ | \ 5.2.2 build Oct 25 2025 15:58:34
2006 - 2024 Copyright by RT-Thread team
lwIP-2.1.2 initialized!
[I/drv_i2c] i2c0 clock=100000000Hz
[I/drv_i2c] i2c0 master mode
[I/sal.skt] Socket Abstraction Layer initialize success.
[I/utest] utest is initialize success.
[I/utest] total utest testcase num: (4)
[I/drivers.serial] Using /dev/ttyS0 as default console
tmpfs mounted on /dev/shm success!
file system initialization done!
Press any key to stop init process startup ... 3
Press any key to stop init process startup ... 2
Press any key to stop init process startup ... 1
Starting init ...
Hello RISC-V
msh />utest_run bsp.k230.drivers.i2c
[I/utest] [] [ utest ] loop 1/1
[I/utest] [] [ utest ] started
[I/utest] [----------] [ testcase ] (bsp.k230.drivers.i2c) started
[I/utest] i2c bus(pin: 48, 49) is idle, init i2c bus pin
[I/utest] This is a i2c test case.
[I/utest] [==========] utest unit name: (test_i2c0_master_slave)
[I/utest] Read data:
[I/utest] 0xAA
[I/utest] 0xAA
[I/utest] 0xAA
[I/utest] 0xAA
[I/utest] 0xAA
[I/utest] 0xAA
[I/utest] 0xAA
[I/utest] 0xAA
[I/utest] 0xAA
[I/utest] 0xAA
[I/utest] 0xAA
[I/utest] 0xAA
[I/utest] 0xAA
[I/utest] 0xAA
[I/utest] 0xAA
[I/utest] 0xAA
[I/utest] Read data:
[I/utest] 0x55
[I/utest] 0x55
[I/utest] 0x55
[I/utest] 0x55
[I/utest] 0x55
[I/utest] 0x55
[I/utest] 0x55
[I/utest] 0x55
[I/utest] 0x55
[I/utest] 0x55
[I/utest] 0x55
[I/utest] 0x55
[I/utest] 0x55
[I/utest] 0x55
[I/utest] 0x55
[I/utest] 0x55
[I/utest] [ PASSED ] [ result ] testcase (bsp.k230.drivers.i2c)
[I/utest] i2c bus pin deinit.
[I/utest] [----------] [ testcase ] (bsp.k230.drivers.i2c) finished
[I/utest] [] [ utest ] 1 tests from 4 testcase ran.
[I/utest] [ PASSED ] [ result ] 1 tests.
[I/utest] [] [ utest ] finished
msh />