cc.lua

-- dfPlayer mini control by lua for use  with nodemcu
-- version 1.0 November 2017
-- Nikos Georgousis (georgousis.info)
-- Based on Yerke's original work for Arduino from https://forum.banggood.com/forum-topic-59997.html
-- User should pass only command and parameters(if needed). All the rest are calculated in the code
-- Play command: 				dofile("cc.lua").ply(0x0d)
-- Pause command: 			dofile("cc.lua").ply(0x0e)
-- Play file 5 on folder 1: 		dofile("cc.lua").ply(0x0F,0x01,0x05)
-- Volume up: 				dofile("cc.lua").ply(0x04)
-- Volume down: 				dofile("cc.lua").ply(0x05)
-- Volume 20 (of 30 max): 		dofile("cc.lua").ply(0x06,0x00,0x14)
-- Select equalizer preset(Rock):	dofile("cc.lua").ply(0x07,0x00,0x02)
-- Play folder number 02:		dofile("cc.lua").ply(0x17,0x00,0x02)

--Serial communication setup 
uart.setup(0, 9600, 8, uart.PARITY_NONE, uart.STOPBITS_1, 1) -- You can move this line your project's init.lua file.
--Please notice that the above line will switch the communication interface to 9600 baud. Re-connect your programmer using the set baud rate. 

local PL
do
startb = 0x7e 	-- no change 
VER = 0xff		-- no change
Len = 0x06 		-- no change (always 6)
CMD = 0x00		-- command
Feedback = 0x00	-- enable feedback or not
para1 = 0x00	-- command parameter 1
para2 = 0x00	-- command parameter 2
endb = 0xef		-- no change

function ply(InCMD,par1,par2)
CMD = InCMD
--If user pass parameters then replace default values
if par1 ~=nil then
para1 = par1
end 
if par2 ~=nil then
para2 = par2
end 

--Ungly checksum calculation is following
result = -(VER+Len+CMD+Feedback+para1+para2)
output = string.format("%x", result * 256) 
checksumpart1=("0x"..string.sub(output,3,4))
checksumpart2=("0x"..string.sub(output,5,6))
--Send the command to dfplayer module
uart.write(0,tonumber(startb))
uart.write(0,tonumber(VER))
uart.write(0,tonumber(Len))
uart.write(0,tonumber(CMD))
uart.write(0,tonumber(Feedback))
uart.write(0,tonumber(para1))
uart.write(0,tonumber(para2))
uart.write(0,tonumber(checksumpart1))
uart.write(0,tonumber(checksumpart2))
uart.write(0,tonumber(endb))

end

PL={
ply=ply,
}
end
return PL