AS3935 Demo for the Parallax Propeller

AS3935_LC.spin

' AS3935 Lightning Detector -- lostcauz                           10/17/2012

' Thanks Jayson Tautic [www.tautic.com] for the tuning code and creating this awesome board!

' Propeller pins 1..5 == CS - IRQ - SCLK - MISO - MOSI || (connect SI to GND)
' write - 00 pull CS low, write, pull CS high
' read  - 01 register_addr(6 bits) register_data(8 bits)
' read - (CS high,low,high ends read)
' on_events, AS3935 pulls IRQ high and displays the interrupt in the REG0x03[3:0]

con
  _clkmode = xtal1+pll16x
  _clkfreq = 80_000_000

obj              
  pst : "Parallax Serial Terminal"
  
var
  long distance
  long disturber
  long lightning 

pub main
  pst.Start(115200)
  pst.str(string(13,"Lightning Detector ON"))
  cognew(@init,@distance)
  
  repeat             
    case distance
      1:  pst.str(string(13,"Storm is overhead, Lightning #"))
          pst.dec(++lightning) 
      2..40:
          pst.str(string(13,"Storm distance is "))
          pst.dec(distance)
          pst.str(string(" km, Lightning #"))
          pst.dec(++lightning)
      63: pst.str(string(13,"Detected out of range: Lightning #"))
          pst.dec(++lightning)
      65: pst.str(string(13,"Noise level too high"))
      66: pst.str(string(13,"Detected Disturber #"))
          pst.dec(++disturber)                      
    distance := 0          

dat
               org
init           andn     dira,IRQ            ' inputs
               andn     dira,MISO           '
               or       outa,CS             ' preset CS high
               or       dira,CS             ' output
               andn     outa,SCLK           ' preset low 
               or       dira,SCLK           ' output
               andn     outa,MOSI           ' preset low
               or       dira,MOSI           ' output  
               
               mov      t2,cal_rco          ' perform tuning of RCO
               call     #write_data
                                                                                                             
               mov      t2,tune_cap         ' set up tuning caps to tune the antenna to 500kHz resonance. 
               call     #write_data         

               ' Next 2 instructions may be uncommented to mask disturber; also, 1st instruction may be swapped for
               ' raise_NTH | raise_NTH_WDTH | raise_WDTH | NTH_WDTH_def -- explanations of each in definitions below 
               'mov      t2,MASK_DIST        ' ignore disturber
               'call     #write_data 
               
:loop          waitpne  null,IRQ            ' wait for IRQ high
        
               mov      time,cnt            ' must wait 2ms before reading IRQ register 
               add      time,IRQ_delay
               waitcnt  time,IRQ_delay

               mov      t2,read_IRQ         ' register 3 [3..0]
               call     #read_data          ' t2 contains read data
               and      t2,#%1111           ' only need bits[3..0]
                                            ' interrupt value of zero means distance changed due to purging
               test     t2,#1     wz        ' noise 
        if_nz  wrlong   INT_NH,par          ' 65 represents too much noise

               test     t2,#4     wz        ' disturber - if using MASK_DIST above comment out these 2 inst.
        if_nz  wrlong   INT_D,par           ' 66 represents disturber detected                        
       
               test     t2,#8     wz        ' %1000 means lightning detected
        if_z   jmp      #:loop              ' no lightning detected
        
               mov      t2,read_reg7        ' lightning detected, read register 7 [5..0] for distance of storm in km
               call     #read_data
               
               and      t2,#%11_1111        ' only need bits[5..0]
               wrlong   t2,par              ' write distance of storm to par 
               jmp      #:loop

write_data     andn     outa,CS             ' CS low
               mov      t1,#16              ' 16 bits
               
:w_next        rol      t2,#1     wc        ' next bit 
               muxc     outa,MOSI           ' shift bit out to as3935
        
               call     #delay              ' clock data
               or       outa,SCLK
               call     #delay
               andn     outa,SCLK 
               djnz     t1,#:w_next
                    
               or       outa,CS             ' end write
write_data_ret ret

read_data      andn     outa,CS             ' CS low
               mov      t1,#8               ' 8 bits send
               
:send_req      rol      t2,#1     wc        ' next bit 
               muxc     outa,MOSI           ' shift bit out to as3935
               
               call     #delay              ' clock data
               or       outa,SCLK
               call     #delay
               andn     outa,SCLK
               djnz     t1,#:send_req
               
               call     #delay              ' need delay between last low SCLK and upcoming high

               mov      t1,#8               ' 8 bits rec
               xor      t2,t2
               
:rec_bit       or       outa,SCLK           ' clock data
               call     #delay
               andn     outa,SCLK
               call     #delay
               
               test     MISO,ina  wc
               rcl      t2,#1               ' shift bit in to prop
               djnz     t1,#:rec_bit
                              
               or       outa,CS             ' end read
               call     #delay
               andn     outa,CS
               call     #delay
               or       outa,CS
               call     #delay
read_data_ret  ret

delay          mov      time,cnt
               add      time,clk_delay
               waitcnt  time,clk_delay
delay_ret      ret

INT_NH         long     65                  ' noise interrupt
INT_D          long     66                  ' disturber interrupt
IRQ_delay      long     160_000             ' delay 2ms before reading interrupt register
read_IRQ       long     %01_000011 << 24    ' register 3
read_reg7      long     %01_000111 << 24    ' distance of storm in km
CS             long     1 << 1              ' propeller pin connections
IRQ            long     1 << 2              '
SCLK           long     1 << 3              '
MISO           long     1 << 4              '
MOSI           long     1 << 5              '
clk_delay      long     40                  ' 2 MHz
null           long     0                   '
cal_rco        long     %00_111101_1001_0110 << 16 ' perform RCO calibration
tune_cap       long     %00_001000_0000_0100 << 16 ' IRQ pin function for tuning [7..4] tuning caps in 120pf increments [3..0]
'MASK_DIST      long     %00_000011_0010_0000 << 16 ' ignore the disturber
'raise_WDTH     long     %00_000001_0010_0011 << 16 ' raise watchdog threshold only[3..0] (disturber tolerance)////////////////////
'raise_NTH      long     %00_000001_0101_0001 << 16 ' raise noise threshold only[6..4]
'raise_NTH_WDTH long     %00_000001_0101_0101 << 16 ' raise noise threshold[6..4] and watchdog threshold[3..0]
'NTH_WDTH_def   long     %00_000001_0010_0001 << 16 ' reset NTH and WDTH to default values
'show_res_freq  long     %00_001000_1000_0100 << 16 ' show resonance frequency via IRQ with tuned caps
'preset_default long     %00_111100_1001_0110 << 16 ' set registers to default values    
time           res      1                   ' for delay
t1             res      1                   ' temp variables
t2             res      1                   '

               fit