不韋 呂 / UITDSP_ADDA

Class library for internal ADC and DAC connected by SPI. This library support clock generator using TIM3 for switched-capacitor filter to smooth output signal of DAC. This library includes derivative class to support interrupt occured in end of AD conversion. Validated for ST Nucleo F401RE, F411RE. 内蔵 ADC と，SPI 接続の DAC のためのクラスライブラリ．DAC の出力信号を平滑化するためのスイッチトキャパシタフィルタ用のクロックは TIM3 を使用．ST Nucleo F401RE，F411RE で動作を確認．

Dependents:   UITDSP_ADDA_Example UIT2_MovingAv_Intr UIT2_VariableFIR UIT2_VowelSynthesizer ... more

DAC_MCP4921.hpp

Committer:
MikamiUitOpen
Date:
2015-07-25
Revision:
8:543daa087bd5
Parent:
7:14cdca8b48f8

File content as of revision 8:543daa087bd5:

//------------------------------------------------------
// Class for single DAC in MCP4921 -- Header
//      Fast version
//
// Default pin assign
//      D11  SPI Master Out Slave In
//      D13  SPI Serial Clock
//      D10  SPI Slave Select ----------------------- TIM4
//      D12  to MCP4921 LDAC pin
//      D9   clock for Switched-capacitor filter ---- TIM3
//
// Argument cs in constructor must be output of TIM4,
// i.e. D10(PB_6), PB_7, D15(PB_8), or D14(PB_9)
//
// Argument pin in function ScfClockTim3() can be
// PA_6(D12), PB_4(D5), PC_6, PB_5(D4), PC_7(D9),
// PC_8, or PC_9
//
// 2015/03/27, Copyright (c) 2015 MIKAMI, Naoki
//------------------------------------------------------

#ifndef DAC_MCP4921_HPP
#define DAC_MCP4921_HPP

#include "mbed.h"
#include "TIM4_SlaveSelect.hpp"

namespace Mikami
{
    class DAC_MCP4921
    {
    public:
        // Constructor
        DAC_MCP4921(
            PinName mosi = SPI_MOSI,    // D11
            PinName sclk = SPI_SCK,     // D13
            PinName cs   = SPI_CS,      // D10
            PinName ldac = SPI_MISO);   // D12

        // -1.0f <= value <= 1.0f
        void Write(float value)
        {
            if (value < -1.0f) value = -1.0f;
            if (value >  1.0f) value =  1.0f;

            WriteDac((value + 1.0f)*2047);
        }

        // 0 <= value <= 4095
        void Write(uint16_t value)
        {   WriteDac((value > 4095) ? 4095 : value); }

        // Check busy
        bool IsBusy()
        {   return (mySpi_->SR & SPI_SR_BSY) == SPI_SR_BSY; }

        // Set clock for switched-capacitor filter
        void ScfClockTim3(uint32_t clock, PinName pin = D9);

    protected:
        void SlaveSelect() { ss_->SlaveSelect(); }
        void WriteSpi(uint16_t value) { mySpi_->DR = value; }
        
        // generate LDAC negative-going pulse
        void Ldac()
        {
            ld_.write(0);
            ld_.write(0);   // ensure width of "L" pulse
            ld_.write(1);
        }

    private:
        SPI spi_;               // SPI object of mbed
        TIM4_SlaveSelect* ss_;  // Slave Select for DAC
        DigitalOut ld_;         // for LDAC

        // Pointer for SPI
        SPI_TypeDef* mySpi_;

        // for inhibition of copy constructor
        DAC_MCP4921(const DAC_MCP4921&);
        // for inhibition of substitute operator
        DAC_MCP4921& operator=(const DAC_MCP4921&);     
        
        // for internal use
        virtual void WriteDac(uint16_t value)
        {
            while (IsBusy()) {}
            SlaveSelect();
            WriteSpi(value | 0x3000);
        }       
    };
}
#endif  // DAC_MCP4921_HPP