'Code for rotary encoder interpretation by Malcolm Young
'Rotating the encoder prints incremental numbers as appropriate
' eg 0 1 2 3 4 3 2 1 0 -1 -2 etc as well as a direction flag
'in the form of 1 and -1. Developed on Picomite

OPTION ExPLICIT
OPTION DEFAULT NONE

dim float pre_action = 0 'temporarily holds data from new encoder movement
dim float dir_action = 0 'makes "public" the new directional data
dim float inc_action = 0 'makes "public" the new incremental data
dim float old_inc_action = 1 'used to decide if data has changed
dim float clock_enable = 1 'flag to control  clock pin interrupt process
dim float reset_enable = 0 'flag to control data pin interrupt process
dim float clk = 20 'use to name clock pin
dim float dat = 19 'use to name data pin

setpin clk, intl  , clock_interrupt,pullup 'clock pin (encoder pin a)
setpin dat, intb, reset_clock_enable,pullup 'data pin (encoder pin b)

print
print "inc_action", "dir_action"
do
 If inc_action <> old_inc_action then
   print inc_action,, dir_action
   'cls: text 96,60, str$(inc_action),RB,6          'LCD panel output
   old_inc_action = inc_action
 end if
loop

sub clock_interrupt
 if clock_enable = 1 then
   clock_enable=0 'prevents any further "noise" pulses being processed
   if pin(dat) = 1 then 'direction was clockwise
     pre_action = 1
   else                  'direction was counter-clockwise
     pre_action = -1
   endif
   reset_enable=1 'makes reset_clock_enable ready to accept data
 endif
end sub

sub reset_clock_enable
 if reset_enable = 1 then
   reset_enable = 0 'prevents any further "noise" pulses being processed
   if pin(clk) = 0 then 'prevents processing if RE position reverted to origin
      dir_action = pre_action            'directional output
      inc_action=inc_action + pre_action 'incremental output
   endif
   clock_enable = 1 'enables data pin again, even if reverted to origin
 endif  
end sub

Sub zci 'zero count on index
 Pin(85)=0
 spi write 1,&h88
 spi write 1,&h63
 Pin(85)=1
end Sub
Sub nc 'normal quadrature count
 Pin(85)=0
 spi write 1,&h88
 spi write 1,&h43
 Pin(85)=1
end Sub
Sub lci 'load count on index
 Pin(85)=0
 spi write 1,&h88
 spi write 1,&h53
 Pin(85)=1
end Sub
Sub cc 'clear count
 Pin(85)=0
 spi write 1,&h20
 Pin(85)=1
end Sub
Sub es 'encoder status
 pin(85)=0
 spi write 1,&h70
 spi read 1,status()
 pin(85)=1
 print bin$(status(0))
end Sub
Sub clearnc_status
 pin(85)=0
 spi write 1,&h30
 pin(85)=1
end Sub
Sub read_OTR
 pin(85)=0
 spi write 1,&h68
 spi read 4,Indx_latched()
 pin(85)=1
end Sub
Sub tp() 'tell position
 pin(85)=0
 spi write 1,&h60
 spi read 4,psns()
 pin(85)=1
 apos=(psns(1)<<24) or (psns(2)<<16) or (psns(3)<<8) or psns(4)
 if apos and &h80000000 then inc apos, - &hffffffff
 print apos
 print hex$(apos)
end Sub
Sub tp64() 'tell position 64
 pin(85)=0
 spi write 1,&h60
 spi read 4,psns()
 pin(85)=1
 apos=(psns(1)<<24) or (psns(2)<<16) or (psns(3)<<8) or psns(4)
 print apos
 print hex$(apos)
end Sub
Sub dp(cntv) 'define position
 pin(85)=0
 spi write 1,&h98
 spi write 1,(&hff and cntv >> 24)
 spi write 1,(&hff and cntv >> 16)
 spi write 1,(&hff and cntv >> 8)
 spi write 1,(&hff and cntv)
 pin(85)=1
 pin(85)=0
 spi write 1,&he0
 pin(85)=1
end Sub
Sub lc(cntv)'load counter
 pin(85)=0
 spi write 1,&h98
 spi write 1,(&hff and cntv >> 24)
 spi write 1,(&hff and cntv >> 16)
 spi write 1,(&hff and cntv >> 8)
 spi write 1,(&hff and cntv)
 pin(85)=1
end Sub