1 前言

由于串口屏显示图片需要将jpeg文件进行拆包，每个包240字节，尝试结合esp32的sdmmc加载并拆包。

2 硬件

esp32c3+串口屏

在这里插入图片描述
红字标的是串口屏的tx和rx

在这里插入图片描述

3 串口屏配置

选择图标页面平移显示，尺寸设为64、64。（注意和传入的图片尺寸一致），地址设为7FFE
在这里插入图片描述

4 测试数据包

数据帧
5AA5F3828000FFD8FFE000104A46494600010101009000900000FFE100224578696600004D4D002A00000008000101120003000000010001000000000000FFDB0043000201010201010202020202020202030503030303030604040305070607070706070708090B0908080A0807070A0D0A0A0B0C0C0C0C07090E0F0D0C0E0B0C0C0CFFDB004301020202030303060303060C0807080C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0CFFC00011080040004003012200021101031101FFC4001F0000010501010101010100000000000000000102030405

5AA5F3828078060708090A0BFFC400B5100002010303020403050504040000017D01020300041105122131410613516107227114328191A1082342B1C11552D1F02433627282090A161718191A25262728292A3435363738393A434445464748494A535455565758595A636465666768696A737475767778797A838485868788898A92939495969798999AA2A3A4A5A6A7A8A9AAB2B3B4B5B6B7B8B9BAC2C3C4C5C6C7C8C9CAD2D3D4D5D6D7D8D9DAE1E2E3E4E5E6E7E8E9EAF1F2F3F4F5F6F7F8F9FAFFC4001F0100030101010101010101010000000000000102030405060708090A0BFFC400B51100020102040403040705040400

5AA5F38280f0010277000102031104052131061241510761711322328108144291A1B1C109233352F0156272D10A162434E125F11718191A262728292A35363738393A434445464748494A535455565758595A636465666768696A737475767778797A82838485868788898A92939495969798999AA2A3A4A5A6A7A8A9AAB2B3B4B5B6B7B8B9BAC2C3C4C5C6C7C8C9CAD2D3D4D5D6D7D8D9DAE2E3E4E5E6E7E8E9EAF2F3F4F5F6F7F8F9FAFFDA000C03010002110311003F00FDFCA28A2800A28A2800A28A2800A28A2800AFC72FF83AD7F66DF16DD7C0DB5F8A579F17BC69FF0008859EBFE1FD174DF87965B6D343599EE646B8BCBC

5AA5F3828168DA49BC918AC3E56F0BE4946C16DF81FB1B5F34FF00C156FF00E09DFF00F0F3BFD96A1F86BFF0987FC20FE4F882C35DFED1FECAFED2CFD95D9BCAF2BCE87EF671BB7F1E86A63755A8D45F66A425E894D733F3F76FE7DB5B1574E9D483FB5092F9B8BB7FE4D6FD74B9F48587FC78C3FF005CD7F954D4DB78BC88123CE76285CFAE29D572DCC69C5A824FB05145148D028A28A0028A28A0028A28A0028A28A0028A28A0028A28A0028A28A0028A28A0028A28A00FFFD90000

显示命令
5AA507827FFE5AA58000

先用串口工具传输，注意串口波特率115200
在这里插入图片描述

5 代码

5.1 拆分jpeg

table_jpg = {}
table_jpg_num = 0       -- 记录多少个包
function open_jpg(path)
    -- if io.exists(path) == false then
    --     log.info("sdio","error path")
    --     return -1
    -- end
    print(path)

    f_jpg = io.open(path,"rb")
    local jpg_size = io.fileSize(path)
    local jpg_pkg_num = math.ceil(jpg_size/240) --向上取整
    table_jpg_num = jpg_pkg_num

    log.info("sdio", "fileSize", jpg_size,jpg_pkg_num)

    jpg_add_num = 0x8000
    for i = 1, jpg_pkg_num, 1 do

        -- 从文件中获取数据，240个字节为一组包（迪文定义）
        local temp_jpg_value_hex = f_jpg:read(240)
        -- pack.pack( b, temp_jpg_value)

        -- 报头
        jpg_head_char = "5AA5F382"

        -- 地址
        jpg_add_char = string.format("%x",jpg_add_num)
        jpg_add_hex = string.fromHex(jpg_add_char)
        print(jpg_add_char)
        jpg_add_num = jpg_add_num+0x78

        -- 数据包
        -- 最后一个报附加0000
        if i == jpg_pkg_num then
            print("end pakage")
            temp_jpg_value_hex = string.fromHex(string.toHex(temp_jpg_value_hex).."0000")
        end

        temp_jpg_value_char = string.toHex(temp_jpg_value_hex)
        -- print(temp_jpg_value_char)

        -- 拼接报头，地址，数据包，并转为16进制用于发送
        uart2dwin_char = jpg_head_char..jpg_add_char..temp_jpg_value_char
        uart2dwin_hex = string.fromHex(uart2dwin_char)
        print(uart2dwin_char)

        -- 存储当前的几个包
        table_jpg[i]=uart2dwin_hex
    end
    f_jpg:close()
end

这样可以将jpeg数据拆分为一包240数据，然后加上报头以及最后附加0000

5.2 串口

tag_uart = "t5_uart"

uart_id = 1
uart_speed = 115200
len = 1024

function init_uart()
    -- uart.on(1, "recv", function(uart_id, len)
    --     local data = uart.read(1, 1024)
    --     log.info("uart2", data)
    --     -- libgnss.parse(data)
    -- end)
    log.info(tag_uart,"test5_init_uart")
    uart.setup(uart_id, uart_speed)

    -- 接收数据
    uart.on(uart_id, "receive",uart_receive)

    -- uart.on(uart_id, "sent",uart_send)
    -- 定时发送数??
    -- timex = sys.timerLoopStart(uart_send,3000)
    -- log.info(tag_uart,"time:",timex)
end

function uart_send()
    log.info("uart_send")
    -- if temp_send_hex ~= nil then
    --     log.info("uart_send",temp_send_hex)
        uart.write(uart_id, 'a')
    -- end
    
end

function uart_receive()
    log.info("uart_receive")
    local s = ""
    s = uart.read(uart_id, len)
    if #s > 0 then -- #s 是取字符串的长度
        -- 如果传输二进??/十六进制数据, 部分字符不可??, 不代表没收到
        -- 关于收发hex??,请查?? https://doc.openluat.com/article/583
        -- log.info("uart", "receive", uart_id, #s, s)
        -- log.info("uart", "receive", uart_id, #s, string.toHex(s))

        dwin_uart2 = string.toHex(s)
        print(dwin_uart2,type(dwin_uart2))


        if dwin_uart2 == "5AA503824F4B" then
            flag_ok = true
        end

        -- 判断传来的地址
        judge_dwin_tx(dwin_uart2)

    end
end

function judge_dwin_tx(str)
    -- 0x1502是发送书名
    if string.find(str,'831502') ~= nil then
        sys.publish("SEND_BOOKNAME", false)
    end

    -- 0x122F是书名
    if string.find(str,'83122F') ~= nil then
        sys.publish("SAVE_BOOKNAME", str)
    end

    -- 0x1300是发送按钮，暂时用于显示jpg
    if string.find(str,'831300') ~= nil then
        sys.publish("DISPLAY_JPG", str)
    end

end

function send_bookname(state)
    log.info("SEND_BOOKNAME", state)
    flag_search = true
end
sys.subscribe("SEND_BOOKNAME", send_bookname)

function save_bookname(str)
    log.info("SAVE_BOOKNAME", str)
    -- local v_start = string.find(str,'83122F')
    -- local value = string.sub(str,v_start+7)

    local dwin_adr_input_ta='83122F'
    dwin_uart2_adr = string.find(str,dwin_adr_input_ta)

    dwin_uart2_start = dwin_uart2_adr + #dwin_adr_input_ta + 4   -- 03 5A(标识??)
    dwin_uart2_len = string.sub(str, dwin_uart2_start, dwin_uart2_start+1)

    dwin_uart2_end = string.find(str,'FFFF')

    local dwin_uart2_gbk_char = nil
    dwin_uart2_gbk_char = string.sub(str, dwin_uart2_start+2, dwin_uart2_end-1)

    dwin_uart2_gbk_hex = string.fromHex(dwin_uart2_gbk_char)
    print("dwin_uart2_gbk_hex",dwin_uart2_gbk_hex,#dwin_uart2_gbk_hex)


    temp_bookname = dwin_uart2_gbk_hex
end
sys.subscribe("SAVE_BOOKNAME", save_bookname)


function recv_jpg_pkg(state)
    log.info("RECV_JPG_PKG", state)
    -- flag_search = true
end
sys.subscribe("RECV_JPG_PKG", recv_jpg_pkg)

dwin_tx_jpg_display = "5AA507827FFE5AA58000"
function display_jpg(state)
    log.info("DISPLAY_JPG", state)

    -- send_table_jpg()
    flag_display_jpg = true

end
sys.subscribe("DISPLAY_JPG", display_jpg)

function send_table_jpg()
    for i=1,table_jpg_num do
        flag_ok = false
        while true do
            
            if flag_ok == false then
                print("send pkg:",i)
                uart.write(uart_id, table_jpg[i])
                -- print(table_jpg[i])
                print("send ok")
                sys.wait(200)
            else
                break
            end
        end
    end

    print("start display")
    flag_ok = false
    while true do
        if flag_ok == false then
            -- 发送显示命令
            uart.write(uart_id, string.fromHex(dwin_tx_jpg_display))
            sys.wait(100)
        else
            break
        end
    end
    print("end display")
end