Class library for internal ADC and DAC connected by SPI. ADC is triggered by TIM2. 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. Slave select of SPI for DAC is generated using TIM4. Validated for ST Nucleo F401RE, F411RE. New version. 内蔵 ADC と,SPI 接続の DAC のためのクラスライブラリ.ADC の変換開始トリガは TIM2 で発生.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.DAC の SPI 用スレーブ選択信号は TIM4 で発生.ST Nucleo F401RE,F411RE で動作を確認.新バージョン
Dependents: UIT2_MovingAverage UIT2_AllpassReverb UIT2_CombReverb UIT2_FIR_LPF_Symmetry ... more
DAC_MCP4921.hpp
- Committer:
- MikamiUitOpen
- Date:
- 2015-02-02
- Revision:
- 21:3731753ebf24
- Parent:
- 20:c49f3b565a87
File content as of revision 21:3731753ebf24:
//------------------------------------------------------ // 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 // // 2015/02/02, 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((uint16_t)((value + 1.0f)*2047)); } // 0 <= value <= 4095 void Write(uint16_t value) { WriteDac((value > 4095) ? 4095 : value); } // generate LDAC negative-going pulse void Ldac() { ld_.write(0); ld_.write(0); // ensure width of "L" pulse ld_.write(1); } // Check busy bool IsBusy() { return (mySpi_->SR & SPI_SR_BSY) == SPI_SR_BSY; } // Little wait void Wait() { __NOP(); __NOP(); __NOP(); } // 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; } private: SPI spi_; // SPI object of mbed Tim4_ss* ss_; DigitalOut ld_; // for LDAC // Pointer of I2C 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