fl

{
This is translated Single Pin Sigma Delta Driver v1 by Beau Schwabe to PropForth5.5

2013/07/17 16:12:42

}

\ Single Pin Sigma Delta Driver v1
\ ( n1 n2 n3 -- )  n1:ADC accumlator address  n2:samples  n3:A/D pin number
lockdict create a_1pin_sigma_delta_A/D forthentry
$C_a_lxasm w, h124  h113  1- tuck - h9 lshift or here W@ alignl h10 lshift or l,
z2WyPW1 l, zfiPZB l, z1SyLI[ l, z2WiPeB l, z1SyLI[ l, z1[ixmC l, z2WyPr0 l, z2WiPmD l,
z1YFPal l, z1rixZC l, z1bixmC l, 0 l, z1[ixmC l, z20oPr1 l, z3[yPnR l, z8FPuB l,
z1SV04P l,
freedict

variable result
clkfreq d10 u/ constant 100msec

\ Convert VR's center voltage to 0 - 4095 100msec by 100msec
\ ( -- )
: a/d_VR
c" result d4095 6 a_1pin_sigma_delta_A/D" 0 cogx

cnt COG@ 100msec +
begin     
     result L@ . cr
     100msec waitcnt
fkey? swap drop until
0 cogreset
;


{
\ 1-pin SigmaDelta A/D converter
\ ( n1 n2 n3 -- ) n1:ADC accumlator address  n2:samples  n3:A/D pin number
\ $C_treg1 -- ADC Pin mask
\ $C_treg2 -- samples  
\ $C_treg3 -- counter 
\ $C_treg4 -- accumlator 
\ $C_stTOS -- ADC accumlator address

fl
build_BootOpt :rasm
          \ Get ADC Pin mask
          mov       $C_treg1 , # 1         
          shl       $C_treg1 , $C_stTOS
          spop
          \ Get samples
          mov       $C_treg2 , $C_stTOS
          spop
     
          \ Set ADC pin to an input
          andn      dira , $C_treg1          
__1
          \ Clear ADC_Sample
          mov       $C_treg4 , # 0 
          \ Set number of itterations          
          mov       $C_treg3 , $C_treg2      
__2
          \ Read ADC pin ; set Z flag
          test      $C_treg1 , ina wz   
          \ reset ADC pin to opposite state of ADC pin reading       
          muxz      outa , $C_treg1  
          \ Set ADC pin to an output        
          or        dira , $C_treg1   
          \ small delay for charging/discharging       
          nop   
          \ Set ADC pin to an input                             
          andn      dira , $C_treg1     
          \ Increment ADC_accumulator only if cap needed charging     
if_nz     add       $C_treg4 , # 1           
          \ next itteration
          djnz      $C_treg3 , # __2  
          \ write ADC_accumulator back to Spin variable "sample"       
          wrlong    $C_treg4 , $C_stTOS   
          \ read next ADC sample   
          jmp       # __1                    
     
     
;asm a_1pin_sigma_delta_A/D


}