touch.cpp

00001 /*
00002 Touchpad driver.
00003 
00004 CPV, 3/9/2009
00005 */
00006 
00007 #include "touch.h"
00008 
00009 
00010 void TouchpadChannel::initialise(int min, int quantise_step)
00011 {
00012     m_min = min;
00013     m_quantise_step = quantise_step;
00014     m_filter.initialise(8);
00015     m_quantised = -1;
00016 }
00017 
00018 
00019 int TouchpadChannel::quantise(void)
00020 {
00021     m_quantised = -1;
00022     int raw = m_filter();
00023     
00024     if (raw>m_min)
00025     {
00026         m_quantised = 0;
00027         
00028         while(raw>m_quantise_step)
00029         {
00030             raw -= m_quantise_step;
00031             m_quantised += 1;
00032         }
00033     }
00034     return m_quantised;
00035 }
00036 
00037 
00038 //===============================================
00039 
00040 
00041 Touchpad::Touchpad(PinName x0, PinName x1, PinName y0, PinName y1)
00042 {
00043     m_x0 = x0;
00044     m_x1 = x1;
00045     m_y0 = y0;
00046     m_y1 = y1;
00047     m_ch_x.initialise(0.1*0xffff,0.16*0xffff);
00048     m_ch_y.initialise(0.1*0xffff,0.22*0xffff);
00049 }
00050 
00051 
00052 int Touchpad::read(PinName drive_hi, PinName drive_lo, PinName read_hi, PinName read_lo)
00053 {
00054     DigitalOut out1(drive_hi);
00055     DigitalOut out0(drive_lo);
00056     AnalogIn in1(read_hi);
00057     AnalogIn in0(read_lo);
00058     out0 = 0;
00059     out1 = 1;
00060     
00061     return in1.read_u16();
00062 }
00063 
00064 
00065 void Touchpad::tick(void)
00066 {
00067     m_ch_x.tick(read_x());
00068     m_ch_y.tick(read_y());
00069 }