feat(lua_i2c): add basic_i2c.lua demo

2026-05-20 11:51:49 -07:00 · 2026-04-22 17:49:14 +08:00
parent f6e97be31e
commit f4539f2381
1 changed files with 82 additions and 0 deletions
@@ -0,0 +1,82 @@
+-- Scan the I2C bus, read 4 bytes from each detected device, write 4 test bytes,
+-- then read back the same registers to verify the write.
+local i2c = require("i2c")
+
+local I2C_PORT = 0
+local SDA_GPIO = 14
+local SCL_GPIO = 13
+local FREQ_HZ = 400000
+
+local START_REG = 0x00
+local TEST_DATA = {0x12, 0x34, 0x56, 0x78}
+
+local function format_bytes(data)
+    local parts = {}
+    for i = 1, #data do
+        parts[i] = string.format("0x%02X", string.byte(data, i))
+    end
+    return table.concat(parts, " ")
+end
+
+local bus = i2c.new(I2C_PORT, SDA_GPIO, SCL_GPIO, FREQ_HZ)
+
+print(string.format(
+    "[i2c_demo] scanning I2C port=%d sda=%d scl=%d freq=%d",
+    I2C_PORT,
+    SDA_GPIO,
+    SCL_GPIO,
+    FREQ_HZ
+))
+
+local addrs = bus:scan()
+if #addrs == 0 then
+    print("[i2c_demo] no I2C device found")
+    bus:close()
+    print("[i2c_demo] done")
+    return
+end
+
+for _, addr in ipairs(addrs) do
+    print(string.format("[i2c_demo] found device at 0x%02X", addr))
+end
+
+for _, addr in ipairs(addrs) do
+    local dev = bus:device(addr)
+
+    local before = dev:read(4, START_REG)
+    print(string.format(
+        "[i2c_demo] device 0x%02X read 4 bytes from 0x%02X: %s",
+        addr,
+        START_REG,
+        format_bytes(before)
+    ))
+
+    dev:write(TEST_DATA, START_REG)
+    print(string.format(
+        "[i2c_demo] device 0x%02X wrote 4 bytes to 0x%02X: 0x%02X 0x%02X 0x%02X 0x%02X",
+        addr,
+        START_REG,
+        TEST_DATA[1],
+        TEST_DATA[2],
+        TEST_DATA[3],
+        TEST_DATA[4]
+    ))
+
+    local after = dev:read(4, START_REG)
+    print(string.format(
+        "[i2c_demo] device 0x%02X read back 4 bytes from 0x%02X: %s",
+        addr,
+        START_REG,
+        format_bytes(after)
+    ))
+
+    if after == string.char(TEST_DATA[1], TEST_DATA[2], TEST_DATA[3], TEST_DATA[4]) then
+        print(string.format("[i2c_demo] device 0x%02X write verification OK", addr))
+    else
+        print(string.format("[i2c_demo] device 0x%02X write verification FAILED", addr))
+    end
+
+    dev:close()
+end
+bus:close()
+print("[i2c_demo] done")