at42qt2120.cpp

00001 //
00002 // Filename: at42qt2120.cpp
00003 //
00004 // Atmel AT42QT2120 12 channel touch sensor.
00005 //
00006 
00007 #include "at42qt2120.h"
00008 
00009 #include "log.h"
00010 
00011 namespace HAL {
00012 
00013 // This chip has a singe fixed I2C address.
00014 const int ADDRESS =  0x1c;
00015 
00016 // Chip Id hardcoded in the silicon.
00017 const int AT42QT2120_ID = 0x3e;
00018     
00019 AT42QT2120::AT42QT2120(I2C &i2cin)
00020 : i2c(i2cin)
00021 {
00022 #ifdef VERBOSE
00023     if(Read((REG_AT42QT2120) QT_CHIP_ID) != AT42QT2120_ID)
00024         Log("AT42QT2120 bad chip id");
00025     else
00026         Log("AT42QT2120 chip id: Ok");
00027     
00028     char version[20];
00029     int ver = Read((REG_AT42QT2120) QT_FIRMWARE_VERSION);
00030     sprintf(version, "AT42QT2120 version: %u.%u", ver >> 4, ver & 0x0f);
00031     Log(version);
00032 #endif
00033 
00034     for(uint8_t key = 0; key < 12; key++)
00035         SetKeyControl(key, false, 0, false, false);
00036 
00037     Calibrate();
00038 }
00039 
00040 bool AT42QT2120::ReadStatus(Status &status)
00041 {
00042     char buffer[4];
00043 
00044     buffer[0] = Read(QT_DETECTION_STATUS);
00045     buffer[1] = Read(QT_KEY_STATUS);
00046     buffer[2] = Read(QT_KEY_STATUS2);
00047     buffer[3] = Read(QT_SLIDER_POSITION);
00048 
00049 #ifdef VERBOSE
00050     char msg[32];
00051     sprintf(msg, "Touch: %x %x %x %x", buffer[0], buffer[1], buffer[2], buffer[3]);
00052 #endif
00053 
00054     status.keyschanged = (buffer[0] & TDET) != 0;
00055     status.keys = buffer[2];
00056     status.keys = status.keys << 8;
00057     status.keys += buffer[1];
00058 
00059     status.sliderchanged = (buffer[0] & SDET) != 0;
00060     status.slider = buffer[3];
00061 
00062     return true;
00063 }
00064 
00065 bool AT42QT2120::Calibrate()
00066 {
00067 #ifdef VERBOSE
00068     Log("AT42QT2120 calibration start");
00069 #endif
00070 
00071     bool status = Write(QT_CALIBRATE, 0xff);
00072     if(status)
00073     {
00074         while(Read(QT_DETECTION_STATUS) & 0x80);
00075     }
00076 
00077 #ifdef VERBOSE
00078     if(status)
00079         Log("AT42QT2120 calibration finish");
00080     else
00081         Log("AT42QT2120 calibration fail");
00082 #endif
00083     return status;
00084 }
00085 
00086 bool AT42QT2120::SetKeyControl(uint8_t key, bool guard, uint8_t group, bool gpo, bool enable)
00087 {
00088     bool status = false;
00089 
00090     if(key < 12 && group < 4)
00091     {
00092         uint8_t config = 0;
00093         if(!enable)
00094             config |= CTRL_EN;
00095         if(gpo)
00096             config |= CTRL_GPO;
00097         if(group)
00098             config |= group << 2;
00099         if(guard)
00100             config |= CTRL_GUARD;
00101 
00102         uint8_t reg = key + 28; // 28 = QT_KEY0_CTRL
00103         status = Write((HAL::REG_AT42QT2120) reg, config);
00104     }
00105 
00106     return status;
00107 }
00108 
00109 void AT42QT2120::SetSliderOptions(SLIDERMODE_AT42QT2120 mode)
00110 {
00111     switch(mode)
00112     {
00113         case SLIDER:
00114             Write(QT_SLIDER_OPTION, 0x80);
00115             break;
00116 
00117         case WHEEL:
00118             Write(QT_SLIDER_OPTION, 0xc0);
00119             break;
00120 
00121         default:
00122             Write(QT_SLIDER_OPTION, 0x0);
00123             break;
00124     }
00125 }
00126 
00127 int AT42QT2120::Read(REG_AT42QT2120 reg)
00128 {
00129     if(i2c.write(ADDRESS << 1, (const char *) &reg, 1, true))
00130     {
00131         i2c.stop();
00132         return 0;
00133     }
00134 
00135     char data[2];
00136     i2c.read(ADDRESS << 1, data, 1);
00137 
00138     return data[0];
00139 }
00140 
00141 bool AT42QT2120::Write(REG_AT42QT2120 reg, uint8_t value)
00142 {
00143     uint8_t regnum = reg;
00144     const char data[2] = { regnum, value };
00145 
00146     return i2c.write(ADDRESS << 1, data, 2) == 0;
00147 }
00148 
00149 } // End HAL namespace.
00150