// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *  
// A to D code for using the built in
// a to d converters, provides some simple routines for using
// the LCP ARM ADC facility. This only covers channel 0
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *  

// REQUIRES:
// #URL-lib "http://pin1.org/forthlib/flb/General/pinsel.flb"
// #URL-lib "http://pin1.org/forthlib/flb/General/soft1.flb"

// CONSTANTS:
// ADC Registers
&e0034000 constant AD0CR
&e0034004 constant AD0GDR
&e0034028 constant ADDR6 
// division constant for A to D, creates a constant
// cdiv based on PCLK
pclk 3500000 / constant CDIV

// AD pins on the LPC 3212 are:
// AD0 = p0.27: 27 1 PINSELECT
// AD1 = p0.28: 28 1 PINSELECT
// AD2 = p0.29: ETC.
// AD3 = p0.30
// AD4 = p0.25
// AD5 = p0.26
// AD6 = p0.4   4 3 PINSELECT
// AD7 = p0.5   5 3 PINSELECT
// NOTE channels are always connected, must use
// pinselect first. to select function 1:
// e.g. 27 1 pinselect

// *******************************************************
// History:
// Mar 2007 Adjustments for ANSI and new board
// *******************************************************

// get 10 bit value when conversion complete
: <0>getad
    begin
        AD0GDR @
        &80000000 and
    until
    AD0GDR @ 6 rshift // move
    &3ff and            // mask relevant
;

// *** Use pinselect first ***
// *** To set up required channels **** 
// e.g. 27 1 pinselect // sets AD0      
// select channel to convert 0..7
// stays until conversion complete
//  ( channel --- )
: <0>AtoD
    1 swap lshift   // move to correct bit
    CDIV 8 lshift + // shift clock and add
    &01200000       // enable + start convertor
    +
    AD0CR !
    getad
;    

// Gets the voltage on the selected AtoD pin
// the voltage range is 0.00 to 3.3 and Vref is 3.3V
// 3.3V / 1023 is 0.003226V per unit
// the calculation is (3.3/1023)*AtoD or
// 0.0032223 * AtoD
// ( channel --- mV)
: <0>Vin@
    AtoD        // get channel value
    3226 *      // value in uV
    1000 u/mod  // get mV value
    swap 500 > if 1+ then // round up
;