drivers/dac/mcp4901/mcp4901.c

   1 /**************************************************************************/
   2 /*!
   3     @file     mcp4901.c
   4     @author   Tauon
   5
   6     @section LICENSE
   7
   8     Software License Agreement (BSD License)
   9
  10     Copyright (c) 2012, Tauon
  11     All rights reserved.
  12
  13     Redistribution and use in source and binary forms, with or without
  14     modification, are permitted provided that the following conditions are met:
  15     1. Redistributions of source code must retain the above copyright
  16     notice, this list of conditions and the following disclaimer.
  17     2. Redistributions in binary form must reproduce the above copyright
  18     notice, this list of conditions and the following disclaimer in the
  19     documentation and/or other materials provided with the distribution.
  20     3. Neither the name of the copyright holders nor the
  21     names of its contributors may be used to endorse or promote products
  22     derived from this software without specific prior written permission.
  23
  24     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
  25     EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  26     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  27     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
  28     DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  29     (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  30     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  31     ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  32     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  33     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34 */
  35 /**************************************************************************/
  36 #include "mcp4901.h"
  37
  38 #define DAC_BUF  0
  39 #define DAC_GA   1
  40 #define DAC_SHDN 1
  41 #define DAC_BITS8
  42
  43 uint16_t settings;
  44
  45 // Control pins
  46 #define MCP4901_GPIODATAREG     (*(pREG32 (0x50023FFC)))   // GPIO2DATA
  47 #define MCP4901_PORT            (2)
  48
  49 #define MCP4901_LDAC            (0)
  50 #define MCP4901_CS_PIN          (6)
  51 #define MCP4901_SCL_PIN         (7)
  52 #define MCP4901_SDI_PIN         (8)
  53
  54 // Macros for control line state
  55 #define CLR_SDI     do { MCP4901_GPIODATAREG &= ~(1<<MCP4901_SDI_PIN); } while(0)
  56 #define SET_SDI     do { MCP4901_GPIODATAREG &= ~(1<<MCP4901_SDI_PIN); MCP4901_GPIODATAREG |= (1<<MCP4901_SDI_PIN); } while(0)
  57 #define CLR_SCL     do { MCP4901_GPIODATAREG &= ~(1<<MCP4901_SCL_PIN); } while(0)
  58 #define SET_SCL     do { MCP4901_GPIODATAREG &= ~(1<<MCP4901_SCL_PIN); MCP4901_GPIODATAREG |= (1<<MCP4901_SCL_PIN); } while(0)
  59 #define CLR_CS      do { MCP4901_GPIODATAREG &= ~(1<<MCP4901_CS_PIN); } while(0)
  60 #define SET_CS      do { MCP4901_GPIODATAREG &= ~(1<<MCP4901_CS_PIN); MCP4901_GPIODATAREG |= (1<<MCP4901_CS_PIN); } while(0)
  61
  62 /*************************************************/
  63
  64 void mcpWriteData(uint8_t data)
  65 {
  66   uint8_t i = 0;
  67   for (i=0; i<8; i++)
  68   {
  69     if (data & 0x80)
  70     {
  71         SET_SDI;
  72     }
  73     else
  74     {
  75
  76         CLR_SDI;
  77     }
  78     data <<= 1;
  79     CLR_SCL;
  80     SET_SCL;
  81   }
  82 }
  83
  84 /*************************************************/
  85 void mcpWriteData16(uint16_t data)
  86 {
  87         mcpWriteData((data>>8) & 0xFF);
  88         mcpWriteData(data & 0xFF);
  89 }
  90
  91 void  mcp4901Init()
  92 {
  93         settings = (DAC_BUF << 2 | DAC_GA << 1 | DAC_SHDN) << 12;
  94         gpioSetDir(MCP4901_PORT, MCP4901_LDAC   , gpioDirection_Output);
  95         gpioSetDir(MCP4901_PORT, MCP4901_CS_PIN , gpioDirection_Output);
  96         gpioSetDir(MCP4901_PORT, MCP4901_SCL_PIN, gpioDirection_Output);
  97         gpioSetDir(MCP4901_PORT, MCP4901_SDI_PIN, gpioDirection_Output);
  98 }
  99 void mcp4901ChangeSettings(bool BUFFER, bool GAIN, bool SHUTDOWN)
 100 {
 101         settings = (BUFFER << 2 | GAIN << 1 | (!SHUTDOWN)) << 12;
 102 }
 103 void mcp4901LDAC(void)
 104 {
 105         gpioSetValue(MCP4901_PORT,MCP4901_LDAC,0);
 106         gpioSetValue(MCP4901_PORT,MCP4901_LDAC,1);
 107 }
 108 void mcp4901SetVoltage( uint8_t output)
 109 {
 110         uint16_t data;
 111         #ifdef DAC_BITS8
 112         data = settings  | (output << 4);
 113         #endif
 114
 115         #ifdef DAC_BITS10
 116         data = settings | (output << 2);
 117         #endif
 118
 119         #ifdef DAC_BITS12
 120         data = settings | output;
 121         #endif
 122         CLR_CS;
 123         mcpWriteData16(data);
 124         SET_CS;
 125 }
 126
 127