Air724UG I2C 讀取ATH10 BH1750

節流計劃旨在降低物聯網產品的硬體成本，本專欄將在2021年持續更新，

節流計劃不采用STM32/STC/PIC等傳統MCU，而是充分挖掘AIR724UG芯片除4G通信外的其他功能，包含但不限于GPIO、TTS、LCD、OTA、FLASH、ADC，KEY，UART，I2C、SPI等，

著作權所有，謝絕轉載，侵權必究，承接相關物聯網專案合作，郵箱：realiot@163.com，

官方例程

1 AHT10資料讀取

sys.taskInit(
    function()
        local i2cid = 2
        local i2cslaveaddr = 0x38

        if i2c.setup(i2cid, i2c.SLOW) ~= i2c.SLOW then
            log.error("AHT10", "i2c.setup fail")
            return
        end

        while true do
            if i2c.send(i2cid, i2cslaveaddr, {0xAC, 0x33, 0x00}) ~= 3 then
                log.error("AHT10", "i2c.send fail")
                return
            end
            sys.wait(100)

            qryResult = i2c.recv(i2cid, i2cslaveaddr, 6)
            if (nil == qryResult) or (6 ~= #qryResult) then
                log.error("ATH10", "i2c.recv fail.")
                return
            end

            log.info("ATH10", "recv", qryResult:toHex())

            sys.wait(2000)
        end
    end
)

2 BH1750資料讀取

local i2cid = 2 --i2cid

local BH1750_ADDRESS_AD0_LOW = 0x23 -- address pin low (GND), default for InvenSense evaluation board
local BH1750_ADDRESS_AD0_HIGH = 0x24 -- address pin high (VCC)

local i2cslaveaddr = BH1750_ADDRESS_AD0_LOW

-- bh1750 registers define
local BH1750_POWER_DOWN = 0x00 -- power down
local BH1750_POWER_ON = 0x01 -- power on
local BH1750_RESET = 0x07 -- reset
local BH1750_CON_H_RES_MODE = 0x10 -- Continuously H-Resolution Mode
local BH1750_CON_H_RES_MODE2 = 0x11 -- Continuously H-Resolution Mode2
local BH1750_CON_L_RES_MODE = 0x13 -- Continuously L-Resolution Mode
local BH1750_ONE_H_RES_MODE = 0x20 -- One Time H-Resolution Mode
local BH1750_ONE_H_RES_MODE2 = 0x21 -- One Time H-Resolution Mode2
local BH1750_ONE_L_RES_MODE = 0x23 -- One Time L-Resolution Mode

local function i2c_send(data)
    i2c.send(i2cid, i2cslaveaddr, data)
end
local function i2c_recv(num)
    local revData = i2c.recv(i2cid, i2cslaveaddr, num)

    return revData
end

local function bh1750_power_on()
    i2c_send(BH1750_POWER_ON)
end

local function bh1750_power_down()
    i2c_send(BH1750_POWER_DOWN)
end

local function bh1750_set_measure_mode(mode, time)
    i2c_send(BH1750_RESET)
    i2c_send(mode)
    sys.wait(time)
end

local function bh1750_read_light()
    bh1750_set_measure_mode(BH1750_CON_H_RES_MODE2, 180)
    local _, light = pack.unpack(i2c_recv(2), ">h")
    light = light / 1.2
    return light
end

local function bh1750_test()
    sys.wait(4000)
    if i2c.setup(i2cid, i2c.SLOW) ~= i2c.SLOW then
        log.error("I2c.init", "fail")
        return
    end
    bh1750_power_on()
    sys.wait(180)
    while true do
        log.info("bh1750_read_light", bh1750_read_light() * 10)
        sys.wait(1000)
    end
end
sys.taskInit(bh1750_test)

實測效果

1、官方代碼可以使用

2、如果AIR724UG上電時傳感器未接入，則任務會return退出，退出任務后即使再接上傳感器，讀取任務也無法繼續運行了，

改進方案

1、 將ATH10和BH1750的讀寫操作放到一個檔案里完成，分時操作不同的傳感器，避免兩個任務同時運行時在某個時間段發送沖突，如此即使沒有檢測到傳感器，整個程式能夠繼續運行，不會報錯或重啟，待傳感器接入恢復正常后，仍然能夠正常讀取傳感器的資料，

2、洗掉出現錯誤后退出任務的return陳述句，

3、I2C的初始化只能運行一次，二次初始化會造成運行錯誤，

sys.taskInit(
    function()
        sys.wait(5000)
        if I2C_OPENED == 0 then
            if i2c.setup(i2cid, i2c.SLOW) ~= i2c.SLOW then
                log.error("I2C_INIT", "i2c.setup fail")
            end
            I2C_OPENED = 1
            log.info("I2C", "I2C_INIT")
        end
        while true do
            if i2c_slave_sta < 2 then
                i2c_slave_sta = i2c_slave_sta + 1
            else
                i2c_slave_sta = 0
            end
            ---[[
            ------------------------------------AHT10
            local aht10_addr = 0x38
            if i2c_slave_sta == 1 then
                if i2c.send(i2cid, aht10_addr, {0xAC, 0x33, 0x00}) ~= 3 then
                    log.error("AHT10", "i2c.send fail")
                end
                sys.wait(200)

                aht10_read = i2c.recv(i2cid, aht10_addr, 6)
                if (nil == aht10_read) or (6 ~= #aht10_read) then
                    log.error("ATH10", "i2c.recv fail.")
                else --正確獲取回傳值
                    --log.info("ATH10", "recv", aht10_read:toHex())

                    local humi = (aht10_read:byte(2) * 65536 + aht10_read:byte(3) * 256 + aht10_read:byte(4))
                    AHT10_HUMI = humi * 100 / 16 / 1024 / 1024
                    local temp =
                        (bit_and(aht10_read:byte(4), 0x0F) * 65536 + aht10_read:byte(5) * 256 + aht10_read:byte(6))
                    AHT10_TEMP = temp * 200 / 1024 / 1024 - 50
                    log.info("ATH10", "HUMI:" .. myfloor(AHT10_HUMI, 2) .. "    TEMP:" .. myfloor(AHT10_TEMP, 2))
                end
            end
            ------------------------------------AHT10
            --]]

            ---[[
            -----------------------------------BH1750
            if i2c_slave_sta == 2 then
                local bh1750_addr_low = 0x23 -- address pin low (GND), default for InvenSense evaluation board
                local bh1750_addr_high = 0x24 -- address pin high (VCC)
                local bh1750_addr = bh1750_addr_high
                -- bh1750 registers define
                local BH1750_POWER_DOWN = 0x00 -- power down
                local BH1750_POWER_ON = 0x01 -- power on
                local BH1750_RESET = 0x07 -- reset
                local BH1750_CON_H_RES_MODE = 0x10 -- Continuously H-Resolution Mode
                local BH1750_CON_H_RES_MODE2 = 0x11 -- Continuously H-Resolution Mode2
                local BH1750_CON_L_RES_MODE = 0x13 -- Continuously L-Resolution Mode
                local BH1750_ONE_H_RES_MODE = 0x20 -- One Time H-Resolution Mode
                local BH1750_ONE_H_RES_MODE2 = 0x21 -- One Time H-Resolution Mode2
                local BH1750_ONE_L_RES_MODE = 0x23 -- One Time L-Resolution Mode

                i2c.send(i2cid, bh1750_addr, BH1750_POWER_ON)
                i2c.send(i2cid, bh1750_addr, BH1750_RESET)
                i2c.send(i2cid, bh1750_addr, BH1750_CON_H_RES_MODE2)
                sys.wait(200)

                local bh1750_read = i2c.recv(i2cid, bh1750_addr, 2)

                if (nil == bh1750_read) or (2 ~= #bh1750_read) then
                    log.error("BH1750", "i2c.recv fail.")
                else --正確獲取回傳值
                    --log.info("BH1750", "recv", bh1750_read:toHex())
                    local _, light = pack.unpack(bh1750_read, ">h")
                    BH1750_LIGHT = light / 1.2
                end
            end
            ------------------------------BH1750
            --]]

            sys.wait(5000)
        end
    end
)
--]]