Qifei 4-bit LED Digital Tube Module, NodeMCU ESP8266

qifei.lua

--Cheap tube module, code for ESP8266 NodeMCU
--depends on ntp.lua
--https://gist.github.com/lucsmall/66d9b6539df7a0daa569
--http://www.esp8266.com/viewtopic.php?p=12733
--http://forum.43oh.com/topic/8596-4-digit-display-from-qifei/
--Qifei 4-bit LED Digital Tube Module, aka 74HC595
--
--D7 -> DIO
--D5 -> sclk
--D4 -> rclk
latch_pin = 4
chars = {
  0xC0, --//0  
  0xF9, --//1
  0xA4, --//2
  0xB0, --//3
  0x99, --//4
  0x92, --//5
  0x82, --//6
  0xF8, --//7
  0x80, --//8
  0x90, --//9
  0x88, --//A
  0x83, --//b
  0xC6, --//C
  0xA1, --//d
  0x86, --//E
  0x8E  --//F
};
ntpobj = loadfile("ntp.lua")()
print(ntpobj)
ntpobj:run(3,1,1800,nil)
tmr.alarm(4,500,1,function()

time = ntpobj:show_time()

digit1 = chars[tonumber(string.sub(time, 1, 1))+1]
digit2 = chars[tonumber(string.sub(time, 2, 2))+1]
digit3 = chars[tonumber(string.sub(time, 4, 4))+1]
digit4 = chars[tonumber(string.sub(time, 5, 5))+1]

end)
 time = nil

digit1 = chars[2]
digit2 = chars[4]
digit3 = chars[4]
digit4 = chars[8]

gpio.mode(latch_pin, gpio.OUTPUT)
gpio.write(latch_pin, gpio.LOW)
result = spi.setup(1, spi.MASTER, spi.CPOL_HIGH, spi.CPHA_LOW, spi.DATABITS_8, 0)
tmr.alarm(1,8,1,function() -- min delay for tmr.alarm == 8us

    gpio.write(latch_pin, gpio.LOW)

    spi.send(1, digit1)
    spi.send(1, tonumber("00001000", 2) )
    gpio.write(latch_pin, gpio.HIGH)
    gpio.write(latch_pin, gpio.LOW)

    spi.send(1, digit2)
    --spi.send(1, bit.band(tonumber("10000110", 2), tonumber("01111111", 2)))
    spi.send(1, tonumber("000000100", 2) )
    gpio.write(latch_pin, gpio.HIGH)

    gpio.write(latch_pin, gpio.LOW)

    spi.send(1, digit3)
    --spi.send(1, bit.band(tonumber("10000110", 2), tonumber("01111111", 2)))
    spi.send(1, tonumber("00000010", 2) )
    gpio.write(latch_pin, gpio.HIGH)

    gpio.write(latch_pin, gpio.LOW)

    spi.send(1, digit4)
    --spi.send(1, bit.band(tonumber("10000110", 2), tonumber("01111111", 2)))
    spi.send(1, tonumber("00000001", 2) )
    gpio.write(latch_pin, gpio.HIGH)
    
    
    --clear
    gpio.write(latch_pin, gpio.LOW)
    spi.send(1, 0x00 )
    gpio.write(latch_pin, gpio.HIGH)
    
end)