'Using 'Bit Twiddling Hacks' (Search on the Internet) pointed to by phil99 ,matherp
 '22/3/2024 - new NECSend routine to replace original due problem with 4.5mS space generation
 'uses the same dev code and key code as the micromite
 
 ' IR Transmit
 Const IRpin = MM.Info$(pinno PE0)  'output pin, change as needed
 SetPin IRpin, dout : Pin(IRpin) = 0 ' IR code output
 ' IR receiver input, fixed as PE2 for F4
 '
 
 Do
   'Your program here.
   Input "Enter Device and Command codes "; dev, key
   NECsend IRpin, dev, key
   
   pause 1000
 Loop
 
 
Sub NECsend IRpin As integer, dev As integer, key As integer
 Local integer word, d(1389), m, n = 1
 'need to reverse  bits in a byte as NEC IR code is sent LSB first
 If dev  < 256 Then ' 8 bit address, so add inverse of address
   DevCode = ((dev * &H0202020202 and &H010884422010) mod 1023)<<8
   DevCode = DevCode + (255-((dev * &H0202020202 and &H010884422010) mod 1023))
 Else ' extended or 16 bit address
   DevCode = (((dev and 255) * &H0202020202 and &H010884422010) mod 1023) << 8
   DevCode = DevCode + ((dev>> 8) * &H0202020202 and &H010884422010) mod 1023
 end if
 KeyCode = (key * &H0202020202 and &H010884422010) mod 1023
 'Check operation of bit reverse code
 print
 print "Input- device ";dev;"   "; bin$(dev);"   key ";key;"   ";Bin$(key)
 print "Output- DevCode "; DevCode;"  ";BIN$(DevCode,16);"  ";"   KeyCode ";KeyCode;"   ";Bin$(KeyCode,8)
 Print
 '
 word = (DevCode<<16) + (KeyCode<<8) + 255-KeyCode 'assemble 32 bits to transmit
 '
 Math set 14 , d() '14=1000/(38*2)uS duration of a half cycle @ 38kHz
 BitBang bitstream IRpin, 670, d() 'send 9ms start 38kHz
 Timer =0
 For m = 43 To 1387 Step 42  'load data sent after start sequence
   d(m) = (((word>>(32-n)) AND 1)*2 + 1) * 562.5  'convert bits to duration (short = 0, long = 1)
   Inc n 'step to next data bit
 Next
 Do : Loop Until Timer > 4.3 'send 4.5ms start space
 BitBang bitstream IRpin, 1387, d() 'send the data
 Pin(IRpin) = 0
End Sub
 

'Using 'Bit Twiddling Hacks' (Search on the Internet) pointed to by phil99 ,matherp
 'uses the same device code and key code as the micromite
 
 'IR receiver input, fixed as PE2 for F4
 
 foreCol% = RGB(white)
 backCol% = rgb(BLACK)
 CLs
 
 IR dev, key , irint 'start the decoder
 Print "   Waiting for IR input"
 text 1,20,"   Waiting for IR input",LT,1,1,foreCol%,backCol%
 Do
   'Your program here.
   
   pause 1000
 Loop
 
 'IR input detected
irint:
 If (dev And &HFF) = ((dev>>8) Xor &HFF) Then ' 8 bit address
   Print "device address 8 bit "
   DevCode = ((dev>>8) * &H0202020202 and &H010884422010) mod 1023
 Else ' extended or 16 bit address
   Print "device address 16 bit "
   DevCode = (((dev and 255) * &H0202020202 and &H010884422010) mod 1023) << 8
   DevCode = DevCode + ((dev>> 8) * &H0202020202 and &H010884422010) mod 1023
 EndIf
 KeyCode = (key * &H0202020202 and &H010884422010) mod 1023
 '
 print "DevCode ";DevCode,"   "; bin$(DevCode,8);"  KeyCode ";KeyCode;"   ";Bin$(KeyCode,8)
 print
 cls
 text 1,20,"Device Code:"+STR$(DevCode)+"  Key Code:"+STR$(KeyCode),LT,1,1,foreCol%,backCol%
 '
 IReturn

Footnote added 2024-03-24 07:25 by phil99
In the event that the program using the NECsend Sub is also using the Timer odd things may hapen when the Sub resets it. These mods fix that.
T = Timer + 4.3 'Replaces Timer = 0
For
...
Next
Do : Loop Until T < Timer 'Replaces Do : Loop Until Timer > 4.3

Also add this line.
Local Float T