'****************************************************************
'*  Name    : ADC_blue_box_03.BAS                               *
'*  Author  : df99                                     *
'*  Notice  : Copyright (c) 2008                                *
'*          : All Rights Reserved                               *
'*  Date    : 1/28/2008                                         *
'*  Version : 1.0                                               *
'*  Notes   : Simple PWM blue box with single pin               *
'*          : keyboard decode                                   *
'****************************************************************

' Resistor network detection values assume a network of 14-1KOhm
' resistors in series, from Vdd to Vss, with a tap between each
' resistor pair. Taps at Vdd and Vss are not used, to avoid ADC
' issues when trying to read at the voltage rails.

' The slight effect of a 250KOhm pull-down resistor on the ADC input
' pin is also factored into the calculations, although the effect is
' almost negligible.

' Set PIC configuration fuses.  PICBASIC PRO refreshes WDT automatically.
' HS_OSC works well for the Murata 20 MHz ceramic resonator. No parallel
' resistor required.

@ DEVICE PIC12F683,HS_OSC,WDT_ON,PWRT_ON,MCLR_ON,BOD_OFF,CPD_OFF,PROTECT_OFF,IESO_OFF,FCMEN_OFF

DEFINE  OSC   20        ' 20 MHz clock

DEFINE ADC_BITS 10      'Use 10 bit resolution with ADCIN
DEFINE ADC_CLOCK 3      'Use internal RC clock for ADC only
DEFINE ADC_SAMPLEUS 50  'Wait 50 uS before read after ADCIN turns on ADC

ADCON0 = %10001001      'Right justify ADC, Vdd ref, Chan 2, enable ADC 

KEY VAR WORD        'Define variable for ADC input value

loop:
    ADCIN 2, KEY                    'Get keypad value again
    Pause 10                        'Allow ADC to settle between reads
    IF (KEY > 37) THEN GOSUB test   'Decode and play if key pressed
    GOTO loop
    
    ' Any key value <= 37 is essentially 0 VDC because of the pull-down
    ' resistor, with some margin for noise. This means that no key has
    ' been pressed.

test:    
    IF ((KEY > 914) AND (KEY <= 1023)) THEN FREQOUT 0,120,700,900     'MF1
    ' 4.64 volts calculated, with Vdd = 5VDC. ADC value=949
    ' Prototype measured value with 5% resistors: 4.65 VDC
    
    IF ((KEY > 841) AND (KEY <= 914))  THEN FREQOUT 0,120,700,1100    'MF2
    ' 4.29 volts calculated, with Vdd = 5VDC. ADC value=878
    ' Mean with previous value = 914
    ' Prototype measured value with 5% resistors: 4.29 VDC
    
    IF ((KEY > 767) AND (KEY <= 841))  THEN FREQOUT 0,120,900,1100    'MF3
    ' 3.93 volts calculated, with Vdd = 5VDC. ADC value=804
    ' Mean with previous value = 841
    ' Prototype measured value with 5% resistors: 3.94 VDC
    
    IF ((KEY > 694) AND (KEY <= 767))  THEN FREQOUT 0,120,700,1300    'MF4
    ' 3.57 volts calculated, with Vdd = 5VDC. ADC value=730
    ' Mean with previous value = 767
    ' Prototype measured value with 5% resistors: 3.58 VDC
    
    IF ((KEY > 621) AND (KEY <= 694))  THEN FREQOUT 0,120,900,1300    'MF5
    ' 3.21 volts calculated, with Vdd = 5VDC. ADC value=657
    ' Mean with previous value = 694
    ' Prototype measured value with 5% resistors: 3.22 VDC
    
    IF ((KEY > 549) AND (KEY <= 621))  THEN FREQOUT 0,120,1100,1300   'MF6
    ' 2.86 volts calculated, with Vdd = 5VDC. ADC value=585
    ' Mean with previous value = 621
    ' Prototype measured value with 5% resistors: 2.86 VDC
    
    IF ((KEY > 475) AND (KEY <= 549))  THEN FREQOUT 0,120,700,1500    'MF7
    ' 2.50 volts calculated, with Vdd = 5VDC. ADC value=512
    ' Mean with previous value = 549
    ' Prototype measured value with 5% resistors: 2.51 VDC
    
    IF ((KEY > 401) AND (KEY <= 475))  THEN FREQOUT 0,120,900,1500    'MF8
    ' 2.14 volts calculated, with Vdd = 5VDC. ADC value=438
    ' Mean with previous value = 475
    ' Prototype measured value with 5% resistors: 2.15 VDC
    
    IF ((KEY > 329) AND (KEY <= 401))  THEN FREQOUT 0,120,1100,1500   'MF9
    ' 1.78 volts calculated, with Vdd = 5VDC. ADC value=364
    ' Mean with previous value = 401
    ' Prototype measured value with 5% resistors: 1.79 VDC
    
    IF ((KEY > 256) AND (KEY <= 329))  THEN FREQOUT 0,120,1100,1700  'KP
    ' 1.43 volts calculated, with Vdd = 5VDC. ADC value=293
    ' Mean with previous value = 329
    ' Prototype measured value with 5% resistors: 1.43 VDC
    
    IF ((KEY > 182) AND (KEY <= 256))  THEN FREQOUT 0,120,1300,1500   'MF0
    ' 1.07 volts calculated, with Vdd = 5VDC. ADC value=219
    ' Mean with previous value = 256
    ' Prototype measured value with 5% resistors: 1.07 VDC
    
    IF ((KEY > 110) AND (KEY <= 182))  THEN FREQOUT 0,120,1500,1700   'ST
    ' 0.71 volts calculated, with Vdd = 5VDC. ADC value=145
    ' Mean with previous value = 182
    ' Prototype measured value with 5% resistors: 0.72 VDC
    
    IF ((KEY > 37)  AND (KEY <= 110))  THEN FREQOUT 0,1000,2600      'Seize
    ' 0.36 volts calculated, with Vdd = 5VDC. ADC value=74
    ' Mean with previous value = 110
    ' Mean with ground (0VDC) = 37
    ' Prototype measured value with 5% resistors: 0.36 VDC   
   
' The following code waits until the key is released (if pressed) to insure
' one tone burst per keypress. Delay seems needed for reliable ADC settling,
' since loop is so small.

    again:
        ADCIN 2, KEY                  'Get keypad value again after tone
        Pause 10                      'Allow ADC to settle between reads
        IF (KEY > 37) THEN again      'Wait for key release
    
    RETURN