In CASE of mystery

Comments

• LA6WNA Posts: 138

  2020-02-07 15:47

  Not sure, but what about moving 64,32 and 16 one step left. To align the first digits with 1 in 128. The other numbers also is to be moved 2 step left.
• Erlend Posts: 612

  2020-02-07 17:52

  Ahh, I never fail to go into the indentation-trap! Thank you!

  CASE gainSel    
        128: bGain:= 7                                                          'gain selected - in dB
        64: bGain:= 6         
        32: bGain:= 5         
        16: bGain:= 4         
        8: bGain:= 3         
        4: bGain:= 2         
        2: bGain:= 1         
        1: bGain:= 0
        OTHER: RETURN FALSE          
      
     regByte:= i2c.ReadByteA8(ChipAddr, CTRL1_CRP) & !bGAINselCTRL1             'blank out the old Gain bits
     i2c.WriteByteA8(ChipAddr, PWR_CTRL, regByte | bGain)                       'write byte with new lower 3 bits representing Gain
     Recal                                                                      'always do re-cal after
     RETURN bGain
  

  Erlend
• JonnyMac Posts: 8,923

  2020-02-07 17:56 edited 2020-02-08 03:23

  The problem is assumed indenting levels. You can left-align the digits, or pad with zeroes to fix the alignment.
  
  Since the outcome is a single variable update, I suggest you replace case with this line: (corrected)

    bGain := lookdownz(gainSel : 1, 2, 4, 8, 16, 32, 64, 128)
  

  IF gainSel is in the list you'll get 0..7 back, otherwise you'll get 0 -- this is exactly what your case is doing.
• Wuerfel_21 Posts: 4,460

  2020-02-07 18:07

  Assuming that you only actually pass in powers of two or zero, you can also do this:

  bGain := ((>|gainSel)-1) #> 0
  

  (other values will get rounded down to the nearest power of two)
• JonnyMac Posts: 8,923

  2020-02-07 18:32 edited 2020-02-07 18:33

  I had originally suggested what @Wuerfel_21 did -- this is better if you have control of gainSel and it's not going to be outside the list of values that you spell out in the case. What her suggestion does, if converted to case, is this:

    case gainSel
      000..001 : bGain := 0
      002..003 : bGain := 1
      004..007 : bGain := 2
      008..015 : bGain := 3    
      016..031 : bGain := 4    
      032..063 : bGain := 5   
      064..127 : bGain := 6    
      128      : bGain := 7    
      other    : bGain := 0
  

  That said, there is no upper limit, so you may want to modify like this:

    bGain := 0 #> >|gainSel-1 <# 7
  

  Warning: If gainSel goes negative, you're always going to get 7 for bGain. You could fix that with:

    if (gainSel > 0)
      bGain := 0 #> >|gainSel-1 <# 7
    else
      bGain := 0
  
• Erlend Posts: 612

  2020-02-07 18:42

  JonnyMac wrote: »

  The problem is assumed indenting levels. You can left-align the digits, or pad with zeroes to fix the alignment.
  
  Since the outcome is a single variable update, I suggest you replace case with this line:

    bGain := lookupz(gainSel : 1, 2, 4, 8, 16, 32, 64, 128)
  

  IF gainSel is in the list you'll get 0..7 back, otherwise you'll get 0 -- this is exactly what your case is doing.

  
  I like this solution a lot. I have several of these parameter list situations, and not all of them are regular like this one.
  
  Erlend
• Erlend Posts: 612

  2020-02-07 22:44

  I did this, though - to not write to the register if not valid

     bGain := LOOKUP(gainSel : 1, 2, 4, 8, 16, 32, 64, 128)                     'convert from desired gain dB to bit numbers to set
     IF bGain == 0                                                              'if not found, do not write to register
       RETURN FALSE
     bGain -= 1                                                                 'because I used lookup instead of lookupz
     regByte:= i2c.ReadByteA8(ChipAddr, CTRL1_CRP) & !bGAINselCTRL1             'blank out the old Gain bits
     i2c.WriteByteA8(ChipAddr, PWR_CTRL, regByte | bGain)                       'write byte with new lower 3 bits representing Gain
     Recal                                                                      'always do re-cal after
     RETURN bGain
  

  Agree?
• Wuerfel_21 Posts: 4,460

  2020-02-07 22:53

  Actually, doesn't it have to be LOOKDOWN instead of LOOKUP?
• JonnyMac Posts: 8,923

  2020-02-08 03:23

  Actually, doesn't it have to be LOOKDOWN instead of LOOKUP?

  You're absolutely right. Clearly, the coffee hadn't kicked in when I made that suggestion this morning. Thanks for the catch.
• Erlend Posts: 612

  2020-02-08 08:43 edited 2020-02-08 09:04

  JonnyMac wrote: »

  Actually, doesn't it have to be LOOKDOWN instead of LOOKUP?

  You're absolutely right. Clearly, the coffee hadn't kicked in when I made that suggestion this morning. Thanks for the catch.

  
  Now I have read the manual (again) and gotten to know that LOOKUP(Z) takes an index and returns the corresponding number in the list, whereas LOOKDOWN(Z) takes a number and returns its index in the list. I need the latter. Thanks @JonnyMac and @Wuerfel_21

     bGain := LOOKDOWN(gainSel : 1, 2, 4, 8, 16, 32, 64, 128)                     'convert from desired gain dB to bit numbers to set
     IF bGain == 0                                                              'if not found, do not write to register
       RETURN FALSE
     bGain -= 1                                                                 'because I used lookdown instead of lookdownz
     regByte:= i2c.ReadByteA8(ChipAddr, CTRL1_CRP) & !bGAINselCTRL1             'blank out the old Gain bits
     i2c.WriteByteA8(ChipAddr, CTRL1_CRP, regByte | bGain)                       'write byte with new lower 3 bits representing Gain
     Recal                                                                      'always do re-cal after
     RETURN gainSel
  
• Erlend Posts: 612

  2020-02-08 11:12

  For the lists that are not contiguous i settled for this code, 'padding' the list with -1, - but it is maybe not very elegant.

  bSPS := LOOKDOWN(SPSsel : 10, 20, 40, 80, -1, -1, -1, 320)
  IF bSPS == 0                                              
    RETURN FALSE                                            
  bSPS -= 1
  

  Erlend
• JonnyMac Posts: 8,923

  2020-02-08 16:12

  If spsSel can never be -1, and the only valid values for bSPS are 0, 1, 2, 3, and 7, that makes sense to me.