'Copyright 2002, Michael G Simpson
'Interface to Radio Shack 270-215 Keypad
func main()

   dim key
   RSkeypadinit()


loop:
   key=RSkeypadread()
   if key <> 0 then
      print key
   endif
   goto loop

endfunc 

'--------------------------------------------------
'Sets up ports for key pad.
'Hardcoded to port 0-7 because of pullups
func RSkeypadinit()
     'Set up ports
   output 2,4,5
   input 3,1,0,6,7

   'Now build custom port
   CUSTOMBIT0 = 3
   CUSTOMBIT1 = 1
   CUSTOMBIT2 = 0
   CUSTOMBIT3 = 6
   CUSTOMBIT4 = 7

   'Set weak Pullups on ports 0-7
   pullupon
endfunc

'-------------------------------------------------
'Tests the keypad
'Returns 0 if no key press
'Returns key 1-15 depending on key
func RSkeypadread()
   dim pdat,res

 'First matrix line
   high 2,4,5
   low 5
   customportget pdat
   pdat = pdat & 31 ^ 31
   
   lookdown res,pdat,1,2,4,8,16
   if res > 0 then
     exit res
   endif

 '2nd matrix line
   high 2,4,5
   low 4
   customportget pdat
   pdat = pdat & 31 ^ 31
   
   lookdown res,pdat,1,2,4,8,16
   if res > 0 then
     exit res + 5
   endif

 '3rd matrix line
   high 2,4,5
   low 2
   customportget pdat
   pdat = pdat & 31 ^ 31
   
   lookdown res,pdat,1,2,4,8,16
   if res > 0 then
     exit res + 10
   endif

   exit 0
endfunc