不韋 呂
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
Diff: DAC_MCP4921.hpp
- Revision:
- 20:c49f3b565a87
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/DAC_MCP4921.hpp Mon Feb 02 08:10:55 2015 +0000
@@ -0,0 +1,98 @@
+//------------------------------------------------------
+// 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