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