MSP430F5529 DriverLib 库函数学习笔记（八）模数转换模块(ADC12)
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MSP430F5529 DriverLib 库函数学习笔记（八）模数转换模块(ADC12)
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目錄
- 硬知識
- 模數轉換概述
- MSP430單片機ADC12模塊介紹
- MSP430單片機ADC12模塊操作
- ADC12的轉換模式
- 采樣和轉換
- 轉換存儲器
- 使用片內集成溫度傳感器
- ADC12模塊寄存器
- ADC_12A API (機翻)
- 處理初始化和轉換的函數
- 參數
- 處理中斷的函數
- 參數
- 處理ADC_12A的輔助功能的函數
- 參數
- 上機實戰
- （使用中斷）參考電壓為AVcc的單通道采樣
- 測量引腳復用輸入
- 配置ADC模塊
- 啟動ADC轉換
- ADC中斷服務函數
- 整體代碼
- 實驗結果
- 采用內部參考電壓的單通道采樣
- 測量引腳復用輸入
- 配置ADC模塊
- 啟動轉換并將結果由串口發送
- 整體代碼
- 實驗結果
- （使用中斷）序列多通道轉換
- 測量引腳復用輸入
- 配置ADC模塊
- 配置采樣存儲器
- 配置ADC中斷
- 開始ADC采樣
- 配置ADC中斷服務函數
- 整體代碼
- 實驗結果
平臺：Code Composer Studio 10.3.1
MSP430F5529 LaunchPad? Development Kit
(MSP?EXP430F5529LP)
硬知識
模數轉換概述
???????在MSP430單片機的實時控制和智能儀表等實際應用系統中，常常會遇到連續變化的物理量，如溫度、流量、壓力和速度等。利用傳感器把這些物理量檢測出來，轉換為模擬電信號，再經過模數轉換模塊（ADC）轉換成數字量，模擬量才能夠被MSP430單片機處理和控制。
1．模數轉換基本過程
???????首先連續時間輸入信號x(t)輸入ADC的采樣保持器中，ADC每隔Ts（采樣周期）讀出一次x(t)的采樣值，對此采樣值進行量化。量化的過程是將此信號轉換成離散時間、離散幅度的多電平信號。從數學角度理解，量化是把一個連續幅度值的無限數集合映射到一個離散幅度值的有限數集合。在進行ADC轉換時，必須把采樣電壓表示為某個規定的最小數量單位的整數倍，所取的最小數量單位叫做量化單位，用Δ表示。顯然，數字信號最低有效位（LSB）的1所代表的數量大小就等于Δ。把量化的結果用代碼表示出來，這個過程稱為編碼。這些代碼就是ADC轉換的輸出結果。
2．ADC的位數
???????ADC的位數為ADC模塊采樣轉換后輸出代碼的位數。例如，一個12位的ADC模塊，采樣轉換后的代碼即為12位，表示數值的取值范圍為0～4095。
3．分辨率
???????分辨率表示輸出數字量變化的一個相鄰數碼所需輸入模擬電壓的變化量。它定義為轉換器的滿刻度電壓與2n的比值，其中n為ADC的位數。因此，分辨率與ADC的位數有關。例如，一個8位ADC模塊的分辨率為滿刻度電壓的1/256。如果滿刻度輸入電壓為5V，該ADC模塊的分辨率即為5V/256=20mV。分辨率代表了ADC模塊對輸入信號的分辨能力，一般來說，ADC模塊位數越高，數據采集的精度就越高。
4．量化誤差
???????量化誤差是由于用有限數字對模擬數值進行離散取值（量化）而引起的誤差。因此，量化誤差理論上為一個單位分辨率，即1/2LSB。量化誤差是無法消除的，但是，通過提高分辨率可以減少量化誤差。
5．采樣周期
???????采樣周期是每兩次采樣之間的時間間隔。采樣周期包括采樣保持時間和轉換時間。采樣保持時間是指ADC模塊完成一次采樣和保持的時間，轉換時間是指ADC模塊完成一次模數轉換所需要的時間。在MSP430單片機的ADC12模塊中，采樣保持時間可通過控制寄存器進行設置，而轉換時間一般需要13個ADCCLK的時間。
6．采樣頻率
???????采樣頻率，也稱為采樣速率或者采樣率，定義為每秒從連續信號中提取并組成離散信號的采樣個數，單位為赫茲(Hz)。采樣頻率的倒數是采樣周期。為了確定對一個模擬信號的采樣頻率，在此簡單介紹采樣定理。采樣定理又稱香農采樣定理或者奈奎斯特采樣定理，即在進行模數信號的轉換過程中，當采樣頻率fs.max大于信號中最高頻率分量fmax的2倍時(fs.max≥2fmax)，采樣之后的數字信號能保留原始信號中的信息。在一般應用中，采樣頻率應為被采樣信號中最高頻率的5～10倍。
7．采樣保持電路
???????采樣保持電路（S/H或者SH）是模數轉換系統中的一種重要電路，其作用是采集模擬輸入電壓在某一時刻的瞬時值，并在模數轉換器進行轉換期間保持輸出電壓不變，以供模數轉換。該電路存在的原因在于模數轉換需要一定時間，在轉換過程中，如果送給ADC的模擬量發生變化，就不能保證采樣的精度。為了簡單起見，在此只分析單端輸入ADC的采樣保持電路，如圖所示。
???????采樣保持電路有兩種工作狀態：采樣狀態和保持狀態。當控制開關S閉合時，輸出跟隨輸入變化，稱為采樣狀態；當控制開關S斷開時，由保持電容C維持該電路的輸出不變，稱為保持狀態。
8．多通道同步采樣和分時復用
???????大多數單片機都集成了8個以上的ADC通道，這些單片機內部的ADC模塊大多都是多通道分時復用的結構，其內部其實只有一個ADC內核，依靠增加模擬開關的方法輪流使用ADC內核，所以可以有多個ADC的輸入通道。MSP430單片機也采用這種結構，如左圖所示。
???????同步采樣ADC實際就是多個完整獨立的ADC。如右圖所示為三通道同步采樣ADC的示意圖。每一組通道都有各自獨立的采樣保持電路和ADC內核，3個ADC模塊共用控制電路和輸入/輸出接口。
MSP430單片機ADC12模塊介紹
ADC12模塊的特性有：
? 高達200ksps的最大轉換率；
? 無數據丟失的單調的12位轉換器；
? 采樣周期可由軟件或定時器編程控制的采樣保持功能；
? 軟件或定時器啟動轉換；
? 可通過軟件選擇片內參考電壓（MSP430F54xx：1.5V或2.5V，其他芯片：1.5V、2.0V或2.5V，注意此處只限MSP430F5xx/6xx系列單片機）；
? 可通過軟件選擇內部或外部參考電壓；
? 高達12路可單獨配置的外部輸入通道；
? 可為內部溫度傳感器、AVCC和外部參考電壓分配轉換通道；
? 正或負參考電壓通道可獨立選擇；
? 轉換時鐘源可選；
? 具有單通道單次、單通道多次、序列通道單次和序列通道多次的轉換模式；
? ADC內核和參考電壓都可獨立關閉；
? 具有18路快速響應的ADC中斷；
? 具有16個轉換結果存儲寄存器。
???????ADC12模塊的結構框圖如圖所示。ADC12模塊支持快速的12位模數轉換。該模塊具有一個12位的逐次逼近（SAR）內核、模擬輸入多路復用器、參考電壓發生器、采樣及轉換所需的時序控制電路和16個轉換結果緩沖及控制寄存器。轉換結果緩沖及控制寄存器允許在沒有CPU干預的情況下，進行多達16路ADC采樣、轉換和保存。
MSP430單片機ADC12模塊操作
ADC12的轉換模式
???????ADC12模塊有4種轉換模式，可以通過CONSEQx控制位進行選擇，具體轉換模式說明如表所示。
（1）單通道單次轉換模式
???????該模式對單一通道實現單次轉換。模數轉換結果被寫入由CSTARTADDx位定義的存儲寄存器ADC12MEMx中。單通道單次轉換的流程圖如圖所示。當用戶利用軟件使ADC12SC啟動轉換時，下一次轉換可以通過簡單地設置ADC12SC位來啟動。當有其他任何觸發源用于轉換時，ADC12ENC位必須在等待觸發信號之前置位（上升沿）。其他的采樣輸入信號將在ADC12ENC復位并置位之前被忽略。
（2）序列通道單次轉換模式
???????該模式對序列通道做單次轉換。ADC12轉換結果將順序寫入由CSTARTADDx位定義的以ADCMEMx開始的轉換存儲器中。當由ADC12MCTLx寄存器中ADC12EOS位定義的最后一個通道轉換完成之后，整個序列通道轉換完成。序列通道單次轉換的流程圖如圖所示。當使用ADC12SC位啟動轉換時，下一次轉換可以通過簡單地設置ADC12SC位來啟動。當有其他任何觸發源用于開始轉換，ADC12ENC位必須在等待觸發信號前置位（上升沿）。其他的采樣輸入信號將在ADC12ENC復位并置位之前被忽略。
（3）單通道多次轉換模式
???????單通道多次轉換模式是在選定的通道上進行多次轉換。ADC轉換的結果被存入由CSTARTADDx位定義的ADC12MEMx寄存器中。在這種轉換模式下，當每次轉換完成后CPU必須讀取ADC12MEMx寄存器的值，否則在下一次轉換中，ADC12MEMx寄存器的值會被覆蓋。單通道多次轉換模式的流程圖如圖所示。在此模式下，若復位ADC12ENC位，則在當前轉換完成之后，轉換將立即停止。同時設置CONSEQx=0和ADC12ENC=0，也可以立即停止當前的轉換，但是，轉換結果是不可靠的。
（4）序列通道多次轉換模式
???????序列通道多次轉換模式用來進行多通道的連續轉換。ADC12轉換結果將順序寫入由CSTARTADDx位定義的以ADCMEMx開始的存儲器中。當由ADC12MCTLx寄存器中ADC12EOS位定義的最后一個通道轉換完成之后，一次序列通道轉換完成，觸發信號會觸發下一次序列通道轉換。序列通道多次轉換模式的流程圖如圖所示。
采樣和轉換
???????當采樣觸發信號SHI出現上升沿時將啟動模數轉換。SHI信號源可以通過SHSx位進行定義，有4種選擇：ADC12SC、Timer_A.OUT1、Timer_B.OUT0、Timer_B.OUT1。ADC12支持8位、10位及12位分辨率模式，可以通過ADC12RES控制位進行選擇，模數轉換分別需要9、11及13個ADC12CLK周期。采樣輸入信號的極性用ISSH控制位來選擇。采樣轉換信號SAMPCON可以來自于采樣輸入信號SHI或采樣定時器，能夠控制采樣的周期及轉換的開始。當SAMPCON信號為高電平時采樣被激活，SAMPCON的下降沿將觸發模數轉換。ADC12SHP定義了兩種不同的采樣時序方法：擴展采樣時序模式和脈沖采樣時序模式。
轉換存儲器
???????典型的模數操作通常用中斷請求的方式來通知ADC轉換的結束，并需要在下一次ADC執行前將轉換結果轉存到另一位置。ADC12中的16個轉換存儲緩沖寄存器（ADC12MEMx）使得ADC可以進行多次轉換而不需要軟件干預，這一點提高了系統性能，也減少了軟件開銷。
???????ADC12模塊的每個ADC12MEMx緩沖寄存器都可通過相關的ADC12MCTLx控制寄存器來配置，為轉換存儲提供了很大的靈活性。SREFx控制位定義了參考電壓，INCHx控制位選擇輸入通道。當使用序列通道轉換模式時，ADC12EOS控制位定義了轉換序列的結束。
使用片內集成溫度傳感器
???????如果需要使用MSP430單片機片內的溫度傳感器，用戶可以選擇模擬輸入通道INCHx=1010。與選擇外部輸入通道一樣，需要進行其他寄存器的配置，包括參考電壓選擇、轉換存儲寄存器選擇等。溫度傳感器典型的轉換函數如圖6.2.12所示，該轉換函數僅僅作為一個示例，實際的參數可以參考具體芯片的數據手冊。當使用溫度傳感器時，采樣周期必須大于30ms。溫度傳感器的偏移誤差比較大，在大多數實際應用中需要進行校準。選擇溫度傳感器會自動地開啟片上參考電壓發生器作為溫度傳感器的電源。但是，它不會使能VREF+輸出或者影響作為模數轉換的參考電壓設置，溫度傳感器的參考電壓設置與其他通道相同。
ADC12模塊寄存器
ADC_12A API (機翻)
ADC_12A API被分成三組函數:
處理初始化和轉換的函數，
處理中斷的函數，
處理ADC_12A的輔助功能的函數。
處理初始化和轉換的函數
ADC12_A_init(uint16_t baseAddress, uint16_t sampleHoldSignalSourceSelect, uint8_t clockSourceSelect, uint16_t clockSourceDivider) //初始化ADC12_A模塊 ADC12_A_configureMemory(uint16_t baseAddress, ADC12_A_configureMemoryParam ?param) //配置所選內存緩沖區的控件 ADC12_A_setupSamplingTimer(uint16_t baseAddress, uint16_t clockCycleHoldCountLowMem, uint16_t clockCycleHoldCountHighMem, uint16_t multipleSamplesEnabled) //設置并啟用采樣定時器脈沖模式 ADC12_A_disableSamplingTimer(uint16_t baseAddress) //禁用采樣定時器脈沖模式 ADC12_A_startConversion(uint16_t baseAddress, uint16_t startingMemoryBufferIndex, uint8_t conversionSequenceModeSelect) //使能/開始模數轉換 ADC12_A_disableConversions(uint16_t baseAddress, bool preempt) //禁止ADC轉換任何信號 ADC12_A_getResults(uint16_t baseAddress, uint8_t memoryBufferIndex) //A Signed Integer of the contents of the specified memory buffer ADC12_A_isBusy(uint16_t baseAddress) //返回ADC12_A核心的忙碌狀態。參數
baseAddress
ADC12_A_BASEsampleHoldSignalSourceSelect
/* is the signal that will trigger a sample-and-hold for an input signal to be converted. This parameter is device specific and sources should be found in the device's datasheet. Valid values are: */ ADC12_A_SAMPLEHOLDSOURCE_SC //[Default] ADC12_A_SAMPLEHOLDSOURCE_1 ADC12_A_SAMPLEHOLDSOURCE_2 ADC12_A_SAMPLEHOLDSOURCE_3 /*This parameter is device specific and sources should befound in the device's datasheet. Modified bits are ADC12SHSx of ADC12CTL1 register.*/clockSourceSelect
/* selects the clock that will be used by the ADC12_A core, and the sampling timer if a sampling pulse mode is enabled. Valid values are: */ ADC12_A_CLOCKSOURCE_ADC12OSC //[Default] - MODOSC 5 MHz oscillator from the UCS ADC12_A_CLOCKSOURCE_ACLK //The Auxiliary Clock ADC12_A_CLOCKSOURCE_MCLK //The Master Clock ADC12_A_CLOCKSOURCE_SMCLK //The Sub-Master Clock //Modified bits are ADC12SSELx of ADC12CTL1 register.clockSourceDivider
/*selects the amount that the clock will be divided. Valid values are:*/ ADC12_A_CLOCKDIVIDER_1 //[Default] ADC12_A_CLOCKDIVIDER_2 ADC12_A_CLOCKDIVIDER_3 ADC12_A_CLOCKDIVIDER_4 ADC12_A_CLOCKDIVIDER_5 ADC12_A_CLOCKDIVIDER_6 ADC12_A_CLOCKDIVIDER_7 ADC12_A_CLOCKDIVIDER_8 ADC12_A_CLOCKDIVIDER_12 ADC12_A_CLOCKDIVIDER_16 ADC12_A_CLOCKDIVIDER_20 ADC12_A_CLOCKDIVIDER_24 ADC12_A_CLOCKDIVIDER_28 ADC12_A_CLOCKDIVIDER_32 /*Modified bits are ADC12PDIV of ADC12CTL2 register; bits ADC12DIVx of ADC12CTL1 register.*/ADC12_A_configureMemoryParam
//***************************************************************************** // //! \brief Used in the ADC12_A_configureMemory() function as the param //! parameter. // //***************************************************************************** typedef struct ADC12_A_configureMemoryParam {//! Is the selected memory buffer to set the configuration for.//! \n Valid values are://! - \b ADC12_A_MEMORY_0 [Default]//! - \b ADC12_A_MEMORY_1//! - \b ADC12_A_MEMORY_2//! - \b ADC12_A_MEMORY_3//! - \b ADC12_A_MEMORY_4//! - \b ADC12_A_MEMORY_5//! - \b ADC12_A_MEMORY_6//! - \b ADC12_A_MEMORY_7//! - \b ADC12_A_MEMORY_8//! - \b ADC12_A_MEMORY_9//! - \b ADC12_A_MEMORY_10//! - \b ADC12_A_MEMORY_11//! - \b ADC12_A_MEMORY_12//! - \b ADC12_A_MEMORY_13//! - \b ADC12_A_MEMORY_14//! - \b ADC12_A_MEMORY_15uint8_t memoryBufferControlIndex;//! Is the input that will store the converted data into the specified//! memory buffer.//! \n Valid values are://! - \b ADC12_A_INPUT_A0 [Default]//! - \b ADC12_A_INPUT_A1//! - \b ADC12_A_INPUT_A2//! - \b ADC12_A_INPUT_A3//! - \b ADC12_A_INPUT_A4//! - \b ADC12_A_INPUT_A5//! - \b ADC12_A_INPUT_A6//! - \b ADC12_A_INPUT_A7//! - \b ADC12_A_INPUT_A8//! - \b ADC12_A_INPUT_A9//! - \b ADC12_A_INPUT_TEMPSENSOR//! - \b ADC12_A_INPUT_BATTERYMONITOR//! - \b ADC12_A_INPUT_A12//! - \b ADC12_A_INPUT_A13//! - \b ADC12_A_INPUT_A14//! - \b ADC12_A_INPUT_A15uint8_t inputSourceSelect;//! Is the reference voltage source to set as the upper limit for the//! conversion stored in the specified memory.//! \n Valid values are://! - \b ADC12_A_VREFPOS_AVCC [Default]//! - \b ADC12_A_VREFPOS_EXT//! - \b ADC12_A_VREFPOS_INTuint8_t positiveRefVoltageSourceSelect;//! Is the reference voltage source to set as the lower limit for the//! conversion stored in the specified memory.//! \n Valid values are://! - \b ADC12_A_VREFNEG_AVSS [Default]//! - \b ADC12_A_VREFNEG_EXTuint8_t negativeRefVoltageSourceSelect;//! Indicates that the specified memory buffer will be the end of the//! sequence if a sequenced conversion mode is selected//! \n Valid values are://! - \b ADC12_A_NOTENDOFSEQUENCE [Default] - The specified memory buffer//! will NOT be the end of the sequence OR a sequenced conversion mode//! is not selected.//! - \b ADC12_A_ENDOFSEQUENCE - The specified memory buffer will be the//! end of the sequence.uint8_t endOfSequence; } ADC12_A_configureMemoryParam;clockCycleHoldCountLowMem
/*sets the amount of clock cycles to sample- and-hold for the higher memory buffers 0-7. Valid values are:*/ ADC12_A_CYCLEHOLD_4_CYCLES //[Default] ADC12_A_CYCLEHOLD_8_CYCLES ADC12_A_CYCLEHOLD_16_CYCLES ADC12_A_CYCLEHOLD_32_CYCLES ADC12_A_CYCLEHOLD_64_CYCLES ADC12_A_CYCLEHOLD_96_CYCLES ADC12_A_CYCLEHOLD_128_CYCLES ADC12_A_CYCLEHOLD_192_CYCLES ADC12_A_CYCLEHOLD_256_CYCLES ADC12_A_CYCLEHOLD_384_CYCLES ADC12_A_CYCLEHOLD_512_CYCLES ADC12_A_CYCLEHOLD_768_CYCLES ADC12_A_CYCLEHOLD_1024_CYCLES /*Modified bits are ADC12SHT0x of ADC12CTL0 register.*/clockCycleHoldCountHighMem
/*sets the amount of clock cycles to sample-and-hold for the higher memory buffers 8-15. Valid values are:*/ ADC12_A_CYCLEHOLD_4_CYCLES //[Default] ADC12_A_CYCLEHOLD_8_CYCLES ADC12_A_CYCLEHOLD_16_CYCLES ADC12_A_CYCLEHOLD_32_CYCLES ADC12_A_CYCLEHOLD_64_CYCLES ADC12_A_CYCLEHOLD_96_CYCLES ADC12_A_CYCLEHOLD_128_CYCLES ADC12_A_CYCLEHOLD_192_CYCLES ADC12_A_CYCLEHOLD_256_CYCLES ADC12_A_CYCLEHOLD_384_CYCLES ADC12_A_CYCLEHOLD_512_CYCLES ADC12_A_CYCLEHOLD_768_CYCLES ADC12_A_CYCLEHOLD_1024_CYCLES /*Modified bits are ADC12SHT1x of ADC12CTL0 register.*/multipleSamplesEnabled
/*allows multiple conversions to start without a trigger signal from the sample/hold signal Valid values are:*/ ADC12_A_MULTIPLESAMPLESDISABLE //[Default] - a timer trigger will be needed to start every ADC conversion. ADC12_A_MULTIPLESAMPLESENABLE //- during a sequenced and/or repeated conversion mode, after the first conversion, no sample/hold signal is necessary to start subsequent sample/hold and convert processes. //Modified bits are ADC12MSC of ADC12CTL0 register.startingMemoryBufferIndex
/*is the memory buffer that will hold the first or only conversion. Valid values are:*/ ADC12_A_MEMORY_0 //[Default] ADC12_A_MEMORY_1 ADC12_A_MEMORY_2 ADC12_A_MEMORY_3 ADC12_A_MEMORY_4 ADC12_A_MEMORY_5 ADC12_A_MEMORY_6 ADC12_A_MEMORY_7 ADC12_A_MEMORY_8 ADC12_A_MEMORY_9 ADC12_A_MEMORY_10 ADC12_A_MEMORY_11 ADC12_A_MEMORY_12 ADC12_A_MEMORY_13 ADC12_A_MEMORY_14 ADC12_A_MEMORY_15 //Modified bits are ADC12STARTADDx of ADC12CTL1 registerconversionSequenceModeSelect
/*determines the ADC operating mode. Valid values are:*/ ADC12_A_SINGLECHANNEL /*[Default] - one-time conversion of a single channel into a single memory buffer.*/ ADC12_A_SEQOFCHANNELS /* - one time conversion of multiple channels into the specified starting memory buffer and each subsequent memory buffer up until the conversion is stored in a memory buffer dedicated as the end-of-sequence by the memory's control register.*/ ADC12_A_REPEATED_SINGLECHANNEL /* - repeated conversions of one channel into a single memory buffer.*/ ADC12_A_REPEATED_SEQOFCHANNELS /* - repeated conversions of multiple channels into the specified starting memory buffer and each subsequent memory buffer up until the conversion is stored in a memory buffer dedicated as the end-of-sequence by the memory's control register.*/ /*Modified bits are ADC12CONSEQx of ADC12CTL1 register.*/preempt
/*specifies if the current conversion should be pre-empted before the end of the conversion. Valid values are:*/ ADC12_A_COMPLETECONVERSION /*- Allows the ADC12_A to end the current conversion before disabling conversions.*/ ADC12_A_PREEMPTCONVERSION /*- Stops the ADC12_A immediately, with unpredictable results of the current conversion.*/memoryBufferIndex
/*is the specified Memory Buffer to read. Valid values are:*/ ADC12_A_MEMORY_0 //[Default] ADC12_A_MEMORY_1 ADC12_A_MEMORY_2 ADC12_A_MEMORY_3 ADC12_A_MEMORY_4 ADC12_A_MEMORY_5 ADC12_A_MEMORY_6 ADC12_A_MEMORY_7 ADC12_A_MEMORY_8 ADC12_A_MEMORY_9 ADC12_A_MEMORY_10 ADC12_A_MEMORY_11 ADC12_A_MEMORY_12 ADC12_A_MEMORY_13 ADC12_A_MEMORY_14 ADC12_A_MEMORY_15處理中斷的函數
ADC12_A_enableInterrupt(uint16_t baseAddress, uint32_t interruptMask) //使能選定的ADC 12_A中斷源 ADC12_A_disableInterrupt(uint16_t baseAddress, uint32_t interruptMask) //禁用選定的ADC12中斷源 ADC12_A_clearInterrupt(uint16_t baseAddress, uint16_t memoryInterruptFlagMask) //清除ADC12_A選擇的中斷標志 ADC12_A_getInterruptStatus(uint16_t baseAddress, uint16_t memoryInterruptFlagMask) //返回所選內存中斷標志的狀態參數
baseAddress
ADC12_A_BASEinterruptMask
//Mask value is the logical OR of any of the following: ADC12_A_IE0 ADC12_A_IE1 ADC12_A_IE2 ADC12_A_IE3 ADC12_A_IE4 ADC12_A_IE5 ADC12_A_IE6 ADC12_A_IE7 ADC12_A_IE8 ADC12_A_IE9 ADC12_A_IE10 ADC12_A_IE11 ADC12_A_IE12 ADC12_A_IE13 ADC12_A_IE14 ADC12_A_IE15 ADC12_A_OVERFLOW_IE ADC12_A_CONVERSION_TIME_OVERFLOW_IEmemoryInterruptFlagMask
/*is a bit mask of the interrupt flags to be cleared. Mask value is the logical OR of any of the following:*/ ADC12_A_IFG0 ADC12_A_IFG1 ADC12_A_IFG2 ADC12_A_IFG3 ADC12_A_IFG4 ADC12_A_IFG5 ADC12_A_IFG6 ADC12_A_IFG7 ADC12_A_IFG8 ADC12_A_IFG9 ADC12_A_IFG10 ADC12_A_IFG11 ADC12_A_IFG12 ADC12_A_IFG13 ADC12_A_IFG14 ADC12_A_IFG15處理ADC_12A的輔助功能的函數
ADC12_A_setResolution(uint16_t baseAddress, uint8_t resolutionSelect) //用于更改轉換數據的分辨率 ADC12_A_setSampleHoldSignalInversion(uint16_t baseAddress, uint16_t invertedSignal) //用于 反相或取消反相 采樣/保持信號 ADC12_A_setDataReadBackFormat(uint16_t baseAddress, uint8_t readBackFormat) //用于設置轉換后的數據的回讀格式 ADC12_A_enableReferenceBurst(uint16_t baseAddress) //Enables the reference buffer's burst ability ADC12_A_disableReferenceBurst(uint16_t baseAddress) //Disables the reference buffer's burst ability ADC12_A_setReferenceBufferSamplingRate(uint16_t baseAddress, uint8_t samplingRateSelect) //用于設置參考緩沖區的采樣率 ADC12_A_getMemoryAddressForDMA(uint16_t baseAddress, uint8_t memoryIndex) //返回DMA模塊的指定內存緩沖區的地址 ADC12_A_enable(uint16_t baseAddress) //啟用ADC12_A模塊 ADC12_A_disable(uint16_t baseAddress) //禁用ADC12_A模塊參數
baseAddress
ADC12_A_BASEresolutionSelect
/*determines the resolution of the converted data. Valid values are:*/ ADC12_A_RESOLUTION_8BIT ADC12_A_RESOLUTION_10BIT ADC12_A_RESOLUTION_12BIT //[Default] //Modified bits are ADC12RESx of ADC12CTL2 registerinvertedSignal
/*set if the sample/hold signal should be inverted Valid values are:*/ ADC12_A_NONINVERTEDSIGNAL /*[Default] - a sample-and-hold of an input signal for conversion will be started on a rising edge of the sample/hold signal.*/ ADC12_A_INVERTEDSIGNAL /*- a sample-and-hold of an input signal for conversion will be started on a falling edge of the sample/hold signal. Modified bits are ADC12ISSH of ADC12CTL1 register.*/readBackFormat
/*is the specified format to store the conversions in the memory buffer. Valid values are:*/ ADC12_A_UNSIGNED_BINARY /*[Default]*/ ADC12_A_SIGNED_2SCOMPLEMENT /*Modified bits are ADC12DF of ADC12CTL2 register*/samplingRateSelect
/*is the specified maximum sampling rate. Valid values are:*/ ADC12_A_MAXSAMPLINGRATE_200KSPS /*[Default]*/ ADC12_A_MAXSAMPLINGRATE_50KSPS /*Modified bits are ADC12SR of ADC12CTL2 register.*/memoryIndex
/*is the memory buffer to return the address of. Valid values are:*/ ADC12_A_MEMORY_0 /*[Default]*/ ADC12_A_MEMORY_1 ADC12_A_MEMORY_2 ADC12_A_MEMORY_3 ADC12_A_MEMORY_4 ADC12_A_MEMORY_5 ADC12_A_MEMORY_6 ADC12_A_MEMORY_7 ADC12_A_MEMORY_8 ADC12_A_MEMORY_9 ADC12_A_MEMORY_10 ADC12_A_MEMORY_11 ADC12_A_MEMORY_12 ADC12_A_MEMORY_13 ADC12_A_MEMORY_14 ADC12_A_MEMORY_15上機實戰
（使用中斷）參考電壓為AVcc的單通道采樣
(改自官方例程)
所用被測信號為配套實驗板的撥盤電位器輸出
信號引腳在0~3.3V之間可調。
測量引腳復用輸入
P6.5對應A5
將P6.5復用輸入
配置ADC模塊
ADC模塊時鐘源選為MODOSC，不分頻
???????內部模塊振蕩器（MODOSC）能夠產生約4.8MHz的MODCLK時鐘。Flash控制器模塊、ADC_12模塊等片內外設都可使用MODCLK作為內部參考時鐘
配置采樣定時器
/** Base address of ADC12_A Module* For memory buffers 0-7 sample/hold for 64 clock cycles* For memory buffers 8-15 sample/hold for 4 clock cycles (default)* Disable Multiple Sampling*/ADC12_A_setupSamplingTimer(ADC12_A_BASE,ADC12_A_CYCLEHOLD_64_CYCLES,ADC12_A_CYCLEHOLD_4_CYCLES,ADC12_A_MULTIPLESAMPLESDISABLE);配置采樣結果緩沖寄存器
選擇輸入信號為A5
正參考電壓源選為AVcc
負參考電壓源選為AVss
配置ADC中斷
因使用的是ADC12_A_MEMORY_0，故使能為Enable memory buffer 0 interrupt
啟動ADC轉換
while(1){//Enable/Start sampling and conversion/** Base address of ADC12_A Module* Start the conversion into memory buffer 0* Use the single-channel, single-conversion mode*/ADC12_A_startConversion(ADC12_A_BASE, ADC12_A_MEMORY_0, ADC12_A_SINGLECHANNEL);//LPM0, ADC12_A_ISR will force exit__bis_SR_register(LPM0_bits + GIE);//for Debugger__no_operation();}ADC中斷服務函數
當被測電壓大于0.5*AVcc時，點亮LED
反之熄滅LED，并打印所測電壓值
case為ADC12_A_MEMORY_0對應的Vector 6
整體代碼
#include "driverlib.h"#define MCLK_IN_HZ 25000000#define delay_us(x) __delay_cycles((MCLK_IN_HZ/1000000*(x))) #define delay_ms(x) __delay_cycles((MCLK_IN_HZ/1000*(x)))void UART_printf(uint16_t baseAddress, const char *format,...); bool UART_Init(uint16_t baseAddress, uint32_t Baudrate);void SystemClock_Init(void) {PMM_setVCore(PMM_CORE_LEVEL_3); //高主頻工作需要較高的核心電壓//XT1引腳復用GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P5, GPIO_PIN4);GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P5, GPIO_PIN5);//起振XT1UCS_turnOnLFXT1(UCS_XT1_DRIVE_3,UCS_XCAP_3);//XT2引腳復用GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P5, GPIO_PIN2);GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P5, GPIO_PIN3);//起振XT2UCS_turnOnXT2(UCS_XT2_DRIVE_4MHZ_8MHZ);//XT2作為FLL參考時鐘，先8分頻，再50倍頻 4MHz / 8 * 50 = 25MHzUCS_initClockSignal(UCS_FLLREF, UCS_XT2CLK_SELECT, UCS_CLOCK_DIVIDER_8);UCS_initFLLSettle(25000, 50);//XT1作為ACLK時鐘源 = 32768HzUCS_initClockSignal(UCS_ACLK, UCS_XT1CLK_SELECT, UCS_CLOCK_DIVIDER_1);//DCOCLK作為MCLK時鐘源 = 25MHzUCS_initClockSignal(UCS_MCLK, UCS_DCOCLK_SELECT, UCS_CLOCK_DIVIDER_1);//DCOCLK作為SMCLK時鐘源 = 25MHzUCS_initClockSignal(UCS_SMCLK, UCS_DCOCLK_SELECT, UCS_CLOCK_DIVIDER_1);//設置外部時鐘源的頻率，使得在調用UCS_getMCLK, UCS_getSMCLK 或 UCS_getACLK時可得到正確值UCS_setExternalClockSource(32768, 4000000); }void ADC_Test_Init(void) {//P6.5 ADC option selectGPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P6,GPIO_PIN5);//Initialize the ADC12_A Module/** Base address of ADC12_A Module* Use internal ADC12_A bit as sample/hold signal to start conversion* USE MODOSC 5MHZ Digital Oscillator as clock source* Use default clock divider of 1*/ADC12_A_init(ADC12_A_BASE,ADC12_A_SAMPLEHOLDSOURCE_SC,ADC12_A_CLOCKSOURCE_ADC12OSC,ADC12_A_CLOCKDIVIDER_1);ADC12_A_enable(ADC12_A_BASE);/** Base address of ADC12_A Module* For memory buffers 0-7 sample/hold for 64 clock cycles* For memory buffers 8-15 sample/hold for 4 clock cycles (default)* Disable Multiple Sampling*/ADC12_A_setupSamplingTimer(ADC12_A_BASE,ADC12_A_CYCLEHOLD_64_CYCLES,ADC12_A_CYCLEHOLD_4_CYCLES,ADC12_A_MULTIPLESAMPLESDISABLE);//Configure Memory Buffer/** Base address of the ADC12_A Module* Configure memory buffer 0* Map input A5 to memory buffer 0* Vref+ = AVcc* Vr- = AVss* Memory buffer 0 is not the end of a sequence*/ADC12_A_configureMemoryParam param = {0};param.memoryBufferControlIndex = ADC12_A_MEMORY_0;param.inputSourceSelect = ADC12_A_INPUT_A5;param.positiveRefVoltageSourceSelect = ADC12_A_VREFPOS_AVCC;param.negativeRefVoltageSourceSelect = ADC12_A_VREFNEG_AVSS;param.endOfSequence = ADC12_A_NOTENDOFSEQUENCE;ADC12_A_configureMemory(ADC12_A_BASE ,¶m);//Enable memory buffer 0 interruptADC12_A_clearInterrupt(ADC12_A_BASE,ADC12IFG0);ADC12_A_enableInterrupt(ADC12_A_BASE,ADC12IE0); }int main(void) {WDT_A_hold(WDT_A_BASE);SystemClock_Init();UART_Init(USCI_A1_BASE, 115200);ADC_Test_Init();GPIO_setAsOutputPin(GPIO_PORT_P1, GPIO_PIN0);while(1){//Enable/Start sampling and conversion/** Base address of ADC12_A Module* Start the conversion into memory buffer 0* Use the single-channel, single-conversion mode*/ADC12_A_startConversion(ADC12_A_BASE, ADC12_A_MEMORY_0, ADC12_A_SINGLECHANNEL);//LPM0, ADC12_A_ISR will force exit__bis_SR_register(LPM0_bits + GIE);//for Debugger__no_operation();} }#pragma vector=ADC12_VECTOR __interrupt void ADC12_A_ISR (void) {uint16_t Measured = 0;switch (__even_in_range(ADC12IV,34)){case 0: break; //Vector 0: No interruptcase 2: break; //Vector 2: ADC overflowcase 4: break; //Vector 4: ADC timing overflowcase 6: //Vector 6: ADC12IFG0//Is Memory Buffer 0 = A5 > 0.5AVcc?Measured = ADC12_A_getResults(ADC12_A_BASE, ADC12_A_MEMORY_0);if (Measured >= 0x7ff){//set P1.0GPIO_setOutputHighOnPin(GPIO_PORT_P1, GPIO_PIN0);}else{//Clear P1.0 LED offGPIO_setOutputLowOnPin(GPIO_PORT_P1, GPIO_PIN0);}UART_printf(USCI_A1_BASE, "Measured_Volt: %f\r\n", (float)Measured/0xfff*3.3);//Exit active CPU__bic_SR_register_on_exit(LPM0_bits);case 8: break; //Vector 8: ADC12IFG1case 10: break; //Vector 10: ADC12IFG2case 12: break; //Vector 12: ADC12IFG3case 14: break; //Vector 14: ADC12IFG4case 16: break; //Vector 16: ADC12IFG5case 18: break; //Vector 18: ADC12IFG6case 20: break; //Vector 20: ADC12IFG7case 22: break; //Vector 22: ADC12IFG8case 24: break; //Vector 24: ADC12IFG9case 26: break; //Vector 26: ADC12IFG10case 28: break; //Vector 28: ADC12IFG11case 30: break; //Vector 30: ADC12IFG12case 32: break; //Vector 32: ADC12IFG13case 34: break; //Vector 34: ADC12IFG14default: break;} }#include <string.h> #include <stdarg.h> #include <stdio.h> void UART_printf(uint16_t baseAddress, const char *format,...) {uint32_t length;va_list args;uint32_t i;char TxBuffer[128] = {0};va_start(args, format);length = vsnprintf((char*)TxBuffer, sizeof(TxBuffer)+1, (char*)format, args);va_end(args);for(i = 0; i < length; i++)USCI_A_UART_transmitData(baseAddress, TxBuffer[i]); }bool UART_Init(uint16_t baseAddress, uint32_t Baudrate) {float UART_Temp = 0;USCI_A_UART_initParam huart = {0};if(baseAddress == USCI_A0_BASE) //P3.3, P3.4 = USCI_A0 TXD/RXD{GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P3, GPIO_PIN3);GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P3, GPIO_PIN4);}else if(baseAddress == USCI_A1_BASE) //P4.4, P4.5 = USCI_A1 TXD/RXD{GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P4, GPIO_PIN4);GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P4, GPIO_PIN5);}if(Baudrate <= 9600){huart.selectClockSource = USCI_A_UART_CLOCKSOURCE_ACLK;UART_Temp = (float)UCS_getACLK()/Baudrate;}else{huart.selectClockSource = USCI_A_UART_CLOCKSOURCE_SMCLK;UART_Temp = (float)UCS_getSMCLK()/Baudrate;}if(UART_Temp < 16)huart.overSampling = USCI_A_UART_LOW_FREQUENCY_BAUDRATE_GENERATION;else{huart.overSampling = USCI_A_UART_OVERSAMPLING_BAUDRATE_GENERATION;UART_Temp /= 16;}huart.clockPrescalar = (int)UART_Temp;if(huart.overSampling == USCI_A_UART_LOW_FREQUENCY_BAUDRATE_GENERATION){huart.secondModReg = (int)((UART_Temp - huart.clockPrescalar) * 8);}else{huart.firstModReg = (int)((UART_Temp - huart.clockPrescalar) * 16);}huart.parity = USCI_A_UART_NO_PARITY;huart.msborLsbFirst = USCI_A_UART_LSB_FIRST;huart.numberofStopBits = USCI_A_UART_ONE_STOP_BIT;huart.uartMode = USCI_A_UART_MODE;if (STATUS_FAIL == USCI_A_UART_init(baseAddress, &huart)){return STATUS_FAIL;}//Enable UART module for operationUSCI_A_UART_enable(baseAddress);//Enable Receive InterruptUSCI_A_UART_clearInterrupt(baseAddress, USCI_A_UART_RECEIVE_INTERRUPT);USCI_A_UART_enableInterrupt(baseAddress, USCI_A_UART_RECEIVE_INTERRUPT);return STATUS_SUCCESS; }//****************************************************************************** // //This is the USCI_A0 interrupt vector service routine. // //****************************************************************************** #pragma vector=USCI_A0_VECTOR __interrupt void USCI_A0_ISR (void) {uint8_t receivedData = 0;switch (__even_in_range(UCA0IV,4)){//Vector 2 - RXIFGcase 2:receivedData = USCI_A_UART_receiveData(USCI_A0_BASE);USCI_A_UART_transmitData(USCI_A0_BASE,receivedData);break;default:break;} }//****************************************************************************** // //This is the USCI_A1 interrupt vector service routine. // //****************************************************************************** #pragma vector=USCI_A1_VECTOR __interrupt void USCI_A1_ISR (void) {uint8_t receivedData = 0;switch (__even_in_range(UCA1IV,4)){//Vector 2 - RXIFGcase 2:receivedData = USCI_A_UART_receiveData(USCI_A1_BASE);USCI_A_UART_transmitData(USCI_A1_BASE,receivedData);break;default:break;} }實驗結果
連上串口，轉動電位器，得到被測信號波形：
采用內部參考電壓的單通道采樣
(改自官方例程)
測量引腳復用輸入
//P6.5 ADC option selectGPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P6, GPIO_PIN5);配置ADC模塊
正參考電壓源選為內部參考電壓，其他部分同上一個實驗
//Initialize the ADC12_A Module/** Base address of ADC12_A Module* Use internal ADC12_A bit as sample/hold signal to start conversion* USE MODOSC 5MHZ Digital Oscillator as clock source* Use default clock divider of 1*/ADC12_A_init(ADC12_A_BASE,ADC12_A_SAMPLEHOLDSOURCE_SC,ADC12_A_CLOCKSOURCE_ADC12OSC,ADC12_A_CLOCKDIVIDER_1);ADC12_A_enable(ADC12_A_BASE);/** Base address of ADC12_A Module* For memory buffers 0-7 sample/hold for 64 clock cycles* For memory buffers 8-15 sample/hold for 4 clock cycles (default)* Disable Multiple Sampling*/ADC12_A_setupSamplingTimer(ADC12_A_BASE,ADC12_A_CYCLEHOLD_64_CYCLES,ADC12_A_CYCLEHOLD_4_CYCLES,ADC12_A_MULTIPLESAMPLESDISABLE);//Configure Memory Buffer/** Base address of the ADC12_A Module* Configure memory buffer 0* Map input A0 to memory buffer 0* Vr+ = Vref+ (int)* Vr- = AVss* Memory buffer 0 is not the end of a sequence*/ADC12_A_configureMemoryParam param = {0};param.memoryBufferControlIndex = ADC12_A_MEMORY_0;param.inputSourceSelect = ADC12_A_INPUT_A5;param.positiveRefVoltageSourceSelect = ADC12_A_VREFPOS_INT;param.negativeRefVoltageSourceSelect = ADC12_A_VREFNEG_AVSS;param.endOfSequence = ADC12_A_NOTENDOFSEQUENCE;ADC12_A_configureMemory(ADC12_A_BASE ,¶m);配置內部參考電壓
//Configure internal reference//If ref generator busy, WAITwhile ( REF_ACTIVE == Ref_isRefGenBusy(REF_BASE) ) ;//Select internal ref = 1.5VRef_setReferenceVoltage(REF_BASE,REF_VREF1_5V);//Internal Reference ONRef_enableReferenceVoltage(REF_BASE);//Delay (~75us) for Ref to settledelay_us(75);其中內部參考電壓可設為1.5V、2V、2.5V
//***************************************************************************** // // The following are values that can be passed to the referenceVoltageSelect // parameter for functions: Ref_setReferenceVoltage(). // //***************************************************************************** #define REF_VREF1_5V (REFVSEL_0) #define REF_VREF2_0V (REFVSEL_1) #define REF_VREF2_5V (REFVSEL_2)啟動轉換并將結果由串口發送
while(1){//Enable/Start first sampling and conversion cycle/** Base address of ADC12_A Module* Start the conversion into memory buffer 0* Use the single-channel, single-conversion mode*/ADC12_A_startConversion(ADC12_A_BASE, ADC12_A_MEMORY_0, ADC12_A_SINGLECHANNEL);//Poll for interrupt on memory buffer 0while (!ADC12_A_getInterruptStatus(ADC12_A_BASE, ADC12IFG0));Measured = ADC12_A_getResults(ADC12_A_BASE, ADC12_A_MEMORY_0);UART_printf(USCI_A1_BASE, "Measured_Volt: %f\r\n", (float)Measured/0xfff*1.5);//SET BREAKPOINT HERE__no_operation();}整體代碼
#include "driverlib.h"#define MCLK_IN_HZ 25000000#define delay_us(x) __delay_cycles((MCLK_IN_HZ/1000000*(x))) #define delay_ms(x) __delay_cycles((MCLK_IN_HZ/1000*(x)))void UART_printf(uint16_t baseAddress, const char *format,...); bool UART_Init(uint16_t baseAddress, uint32_t Baudrate);void SystemClock_Init(void) {PMM_setVCore(PMM_CORE_LEVEL_3); //高主頻工作需要較高的核心電壓//XT1引腳復用GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P5, GPIO_PIN4);GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P5, GPIO_PIN5);//起振XT1UCS_turnOnLFXT1(UCS_XT1_DRIVE_3,UCS_XCAP_3);//XT2引腳復用GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P5, GPIO_PIN2);GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P5, GPIO_PIN3);//起振XT2UCS_turnOnXT2(UCS_XT2_DRIVE_4MHZ_8MHZ);//XT2作為FLL參考時鐘，先8分頻，再50倍頻 4MHz / 8 * 50 = 25MHzUCS_initClockSignal(UCS_FLLREF, UCS_XT2CLK_SELECT, UCS_CLOCK_DIVIDER_8);UCS_initFLLSettle(25000, 50);//XT1作為ACLK時鐘源 = 32768HzUCS_initClockSignal(UCS_ACLK, UCS_XT1CLK_SELECT, UCS_CLOCK_DIVIDER_1);//DCOCLK作為MCLK時鐘源 = 25MHzUCS_initClockSignal(UCS_MCLK, UCS_DCOCLK_SELECT, UCS_CLOCK_DIVIDER_1);//DCOCLK作為SMCLK時鐘源 = 25MHzUCS_initClockSignal(UCS_SMCLK, UCS_DCOCLK_SELECT, UCS_CLOCK_DIVIDER_1);//設置外部時鐘源的頻率，使得在調用UCS_getMCLK, UCS_getSMCLK 或 UCS_getACLK時可得到正確值UCS_setExternalClockSource(32768, 4000000); }void ADC_Test_Init(void) {//P6.5 ADC option selectGPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P6, GPIO_PIN5);//Initialize the ADC12_A Module/** Base address of ADC12_A Module* Use internal ADC12_A bit as sample/hold signal to start conversion* USE MODOSC 5MHZ Digital Oscillator as clock source* Use default clock divider of 1*/ADC12_A_init(ADC12_A_BASE,ADC12_A_SAMPLEHOLDSOURCE_SC,ADC12_A_CLOCKSOURCE_ADC12OSC,ADC12_A_CLOCKDIVIDER_1);ADC12_A_enable(ADC12_A_BASE);/** Base address of ADC12_A Module* For memory buffers 0-7 sample/hold for 64 clock cycles* For memory buffers 8-15 sample/hold for 4 clock cycles (default)* Disable Multiple Sampling*/ADC12_A_setupSamplingTimer(ADC12_A_BASE,ADC12_A_CYCLEHOLD_64_CYCLES,ADC12_A_CYCLEHOLD_4_CYCLES,ADC12_A_MULTIPLESAMPLESDISABLE);//Configure Memory Buffer/** Base address of the ADC12_A Module* Configure memory buffer 0* Map input A0 to memory buffer 0* Vr+ = Vref+ (int)* Vr- = AVss* Memory buffer 0 is not the end of a sequence*/ADC12_A_configureMemoryParam param = {0};param.memoryBufferControlIndex = ADC12_A_MEMORY_0;param.inputSourceSelect = ADC12_A_INPUT_A5;param.positiveRefVoltageSourceSelect = ADC12_A_VREFPOS_INT;param.negativeRefVoltageSourceSelect = ADC12_A_VREFNEG_AVSS;param.endOfSequence = ADC12_A_NOTENDOFSEQUENCE;ADC12_A_configureMemory(ADC12_A_BASE ,¶m);//Configure internal reference//If ref generator busy, WAITwhile ( REF_ACTIVE == Ref_isRefGenBusy(REF_BASE) ) ;//Select internal ref = 1.5VRef_setReferenceVoltage(REF_BASE,REF_VREF1_5V);//Internal Reference ONRef_enableReferenceVoltage(REF_BASE);//Delay (~75us) for Ref to settledelay_us(75); }int main(void) {uint16_t Measured = 0;WDT_A_hold(WDT_A_BASE);SystemClock_Init();UART_Init(USCI_A1_BASE, 115200);ADC_Test_Init();while(1){//Enable/Start first sampling and conversion cycle/** Base address of ADC12_A Module* Start the conversion into memory buffer 0* Use the single-channel, single-conversion mode*/ADC12_A_startConversion(ADC12_A_BASE, ADC12_A_MEMORY_0, ADC12_A_SINGLECHANNEL);//Poll for interrupt on memory buffer 0while (!ADC12_A_getInterruptStatus(ADC12_A_BASE, ADC12IFG0));Measured = ADC12_A_getResults(ADC12_A_BASE, ADC12_A_MEMORY_0);UART_printf(USCI_A1_BASE, "Measured_Volt: %f\r\n", (float)Measured/0xfff*1.5);//SET BREAKPOINT HERE__no_operation();} }#include <string.h> #include <stdarg.h> #include <stdio.h> void UART_printf(uint16_t baseAddress, const char *format,...) {uint32_t length;va_list args;uint32_t i;char TxBuffer[128] = {0};va_start(args, format);length = vsnprintf((char*)TxBuffer, sizeof(TxBuffer)+1, (char*)format, args);va_end(args);for(i = 0; i < length; i++)USCI_A_UART_transmitData(baseAddress, TxBuffer[i]); }bool UART_Init(uint16_t baseAddress, uint32_t Baudrate) {float UART_Temp = 0;USCI_A_UART_initParam huart = {0};if(baseAddress == USCI_A0_BASE) //P3.3, P3.4 = USCI_A0 TXD/RXD{GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P3, GPIO_PIN3);GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P3, GPIO_PIN4);}else if(baseAddress == USCI_A1_BASE) //P4.4, P4.5 = USCI_A1 TXD/RXD{GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P4, GPIO_PIN4);GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P4, GPIO_PIN5);}if(Baudrate <= 9600){huart.selectClockSource = USCI_A_UART_CLOCKSOURCE_ACLK;UART_Temp = (float)UCS_getACLK()/Baudrate;}else{huart.selectClockSource = USCI_A_UART_CLOCKSOURCE_SMCLK;UART_Temp = (float)UCS_getSMCLK()/Baudrate;}if(UART_Temp < 16)huart.overSampling = USCI_A_UART_LOW_FREQUENCY_BAUDRATE_GENERATION;else{huart.overSampling = USCI_A_UART_OVERSAMPLING_BAUDRATE_GENERATION;UART_Temp /= 16;}huart.clockPrescalar = (int)UART_Temp;if(huart.overSampling == USCI_A_UART_LOW_FREQUENCY_BAUDRATE_GENERATION){huart.secondModReg = (int)((UART_Temp - huart.clockPrescalar) * 8);}else{huart.firstModReg = (int)((UART_Temp - huart.clockPrescalar) * 16);}huart.parity = USCI_A_UART_NO_PARITY;huart.msborLsbFirst = USCI_A_UART_LSB_FIRST;huart.numberofStopBits = USCI_A_UART_ONE_STOP_BIT;huart.uartMode = USCI_A_UART_MODE;if (STATUS_FAIL == USCI_A_UART_init(baseAddress, &huart)){return STATUS_FAIL;}//Enable UART module for operationUSCI_A_UART_enable(baseAddress);//Enable Receive InterruptUSCI_A_UART_clearInterrupt(baseAddress, USCI_A_UART_RECEIVE_INTERRUPT);USCI_A_UART_enableInterrupt(baseAddress, USCI_A_UART_RECEIVE_INTERRUPT);return STATUS_SUCCESS; }//****************************************************************************** // //This is the USCI_A0 interrupt vector service routine. // //****************************************************************************** #pragma vector=USCI_A0_VECTOR __interrupt void USCI_A0_ISR (void) {uint8_t receivedData = 0;switch (__even_in_range(UCA0IV,4)){//Vector 2 - RXIFGcase 2:receivedData = USCI_A_UART_receiveData(USCI_A0_BASE);USCI_A_UART_transmitData(USCI_A0_BASE,receivedData);break;default:break;} }//****************************************************************************** // //This is the USCI_A1 interrupt vector service routine. // //****************************************************************************** #pragma vector=USCI_A1_VECTOR __interrupt void USCI_A1_ISR (void) {uint8_t receivedData = 0;switch (__even_in_range(UCA1IV,4)){//Vector 2 - RXIFGcase 2:receivedData = USCI_A_UART_receiveData(USCI_A1_BASE);USCI_A_UART_transmitData(USCI_A1_BASE,receivedData);break;default:break;} }實驗結果
萬用表測得此時P6.5電壓為1.0076V
參考電壓為1.5V時
串口打印電壓為1.015385V，誤差0.77%
（使用中斷）序列多通道轉換
(改自官方例程)
測量引腳復用輸入
由于開發板上只有一個電位器，故將電位器所連的P6.5通過杜邦線再連至P6.4
P6.4、P6.5復用輸入
配置ADC模塊
使能多通道采樣
//Initialize the ADC12_A Module/** Base address of ADC12_A Module* Use internal ADC12_A bit as sample/hold signal to start conversion* USE MODOSC 5MHZ Digital Oscillator as clock source* Use default clock divider of 1*/ADC12_A_init(ADC12_A_BASE,ADC12_A_SAMPLEHOLDSOURCE_SC,ADC12_A_CLOCKSOURCE_ADC12OSC,ADC12_A_CLOCKDIVIDER_1);ADC12_A_enable(ADC12_A_BASE);/** Base address of ADC12_A Module* For memory buffers 0-7 sample/hold for 256 clock cycles* For memory buffers 8-15 sample/hold for 4 clock cycles (default)* Enable Multiple Sampling*/ADC12_A_setupSamplingTimer(ADC12_A_BASE,ADC12_A_CYCLEHOLD_128_CYCLES,ADC12_A_CYCLEHOLD_4_CYCLES,ADC12_A_MULTIPLESAMPLESENABLE);配置采樣存儲器
正參考電壓都設為AVcc
負參考電壓都設為AVss
其中A4不是序列的結尾
A5是序列的結尾
配置ADC中斷
當序列轉換結束，進入中斷，故設為5的中斷
//Enable memory buffer 5 interruptADC12_A_clearInterrupt(ADC12_A_BASE, ADC12IFG5);ADC12_A_enableInterrupt(ADC12_A_BASE, ADC12IE5);開始ADC采樣
開始轉換序列，起始為通道4
模式為序列通道多次轉換
配置ADC中斷服務函數
序列轉換結束進入一次中斷，每累計轉換Num_of_Results次，打印一次電壓平均值。
#pragma vector=ADC12_VECTOR __interrupt void ADC12ISR (void) {static uint16_t index = 0;switch (__even_in_range(ADC12IV,34)){case 0: break; //Vector 0: No interruptcase 2: break; //Vector 2: ADC overflowcase 4: break; //Vector 4: ADC timing overflowcase 6: break; //Vector 6: ADC12IFG0case 8: break; //Vector 8: ADC12IFG1case 10: break; //Vector 10: ADC12IFG2case 12: break; //Vector 12: ADC12IFG3case 14: break; //Vector 14: ADC12IFG4case 16: //Vector 16: ADC12IFG5//Move A4 results, IFG is clearedA4results[index] = ADC12_A_getResults(ADC12_A_BASE, ADC12_A_MEMORY_4);//Move A5 results, IFG is clearedA5results[index] = ADC12_A_getResults(ADC12_A_BASE, ADC12_A_MEMORY_5);//Increment results index, modulo; Set BREAKPOINT hereindex++;if (index == Num_of_Results){float A4_Volt, A5_Volt;uint8_t i = 0;index = 0;for(i = 0, A4_Volt = 0; i < Num_of_Results; i++)A4_Volt += A4results[i];A4_Volt = A4_Volt/10/0xfff*3.3;for(i = 0, A5_Volt = 0; i < Num_of_Results; i++)A5_Volt += A5results[i];A5_Volt = A5_Volt/10/0xfff*3.3;UART_printf(USCI_A1_BASE, "%f %f\r\n", A4_Volt, A5_Volt);}break;case 18: break; //Vector 18: ADC12IFG6case 20: break; //Vector 20: ADC12IFG7case 22: break; //Vector 22: ADC12IFG8case 24: break; //Vector 24: ADC12IFG9case 26: break; //Vector 26: ADC12IFG10case 28: break; //Vector 28: ADC12IFG11case 30: break; //Vector 30: ADC12IFG12case 32: break; //Vector 32: ADC12IFG13case 34: break; //Vector 34: ADC12IFG14default: break;} }整體代碼
#include "driverlib.h"#define MCLK_IN_HZ 25000000#define delay_us(x) __delay_cycles((MCLK_IN_HZ/1000000*(x))) #define delay_ms(x) __delay_cycles((MCLK_IN_HZ/1000*(x)))void UART_printf(uint16_t baseAddress, const char *format,...); bool UART_Init(uint16_t baseAddress, uint32_t Baudrate);void SystemClock_Init(void) {PMM_setVCore(PMM_CORE_LEVEL_3); //高主頻工作需要較高的核心電壓//XT1引腳復用GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P5, GPIO_PIN4);GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P5, GPIO_PIN5);//起振XT1UCS_turnOnLFXT1(UCS_XT1_DRIVE_3,UCS_XCAP_3);//XT2引腳復用GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P5, GPIO_PIN2);GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P5, GPIO_PIN3);//起振XT2UCS_turnOnXT2(UCS_XT2_DRIVE_4MHZ_8MHZ);//XT2作為FLL參考時鐘，先8分頻，再50倍頻 4MHz / 8 * 50 = 25MHzUCS_initClockSignal(UCS_FLLREF, UCS_XT2CLK_SELECT, UCS_CLOCK_DIVIDER_8);UCS_initFLLSettle(25000, 50);//XT1作為ACLK時鐘源 = 32768HzUCS_initClockSignal(UCS_ACLK, UCS_XT1CLK_SELECT, UCS_CLOCK_DIVIDER_1);//DCOCLK作為MCLK時鐘源 = 25MHzUCS_initClockSignal(UCS_MCLK, UCS_DCOCLK_SELECT, UCS_CLOCK_DIVIDER_1);//DCOCLK作為SMCLK時鐘源 = 25MHzUCS_initClockSignal(UCS_SMCLK, UCS_DCOCLK_SELECT, UCS_CLOCK_DIVIDER_1);//設置外部時鐘源的頻率，使得在調用UCS_getMCLK, UCS_getSMCLK 或 UCS_getACLK時可得到正確值UCS_setExternalClockSource(32768, 4000000); }#define Num_of_Results 10 volatile uint16_t A4results[Num_of_Results]; volatile uint16_t A5results[Num_of_Results]; void ADC_Test_Init(void) {//Enable A/D channel inputsGPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P6,GPIO_PIN4 | GPIO_PIN5);//Initialize the ADC12_A Module/** Base address of ADC12_A Module* Use internal ADC12_A bit as sample/hold signal to start conversion* USE MODOSC 5MHZ Digital Oscillator as clock source* Use default clock divider of 1*/ADC12_A_init(ADC12_A_BASE,ADC12_A_SAMPLEHOLDSOURCE_SC,ADC12_A_CLOCKSOURCE_ADC12OSC,ADC12_A_CLOCKDIVIDER_1);ADC12_A_enable(ADC12_A_BASE);/** Base address of ADC12_A Module* For memory buffers 0-7 sample/hold for 256 clock cycles* For memory buffers 8-15 sample/hold for 4 clock cycles (default)* Enable Multiple Sampling*/ADC12_A_setupSamplingTimer(ADC12_A_BASE,ADC12_A_CYCLEHOLD_128_CYCLES,ADC12_A_CYCLEHOLD_4_CYCLES,ADC12_A_MULTIPLESAMPLESENABLE);ADC12_A_configureMemoryParam param = {0};param.positiveRefVoltageSourceSelect = ADC12_A_VREFPOS_AVCC;param.negativeRefVoltageSourceSelect = ADC12_A_VREFNEG_AVSS;//Configure Memory Buffers/** Base address of the ADC12_A Module* Configure memory buffer 4* Map input A4 to memory buffer 4* Vref+ = AVcc* Vref- = AVss* Memory buffer 4 is not the end of a sequence*/param.memoryBufferControlIndex = ADC12_A_MEMORY_4;param.inputSourceSelect = ADC12_A_INPUT_A4;param.endOfSequence = ADC12_A_NOTENDOFSEQUENCE;ADC12_A_configureMemory(ADC12_A_BASE ,¶m);/** Base address of the ADC12_A Module* Configure memory buffer 5* Map input A5 to memory buffer 5* Vr+ = AVcc* Vr- = AVss* Memory buffer 5 IS the end of a sequence*/param.memoryBufferControlIndex = ADC12_A_MEMORY_5;param.inputSourceSelect = ADC12_A_INPUT_A5;param.endOfSequence = ADC12_A_ENDOFSEQUENCE;ADC12_A_configureMemory(ADC12_A_BASE ,¶m);//Enable memory buffer 5 interruptADC12_A_clearInterrupt(ADC12_A_BASE, ADC12IFG5);ADC12_A_enableInterrupt(ADC12_A_BASE, ADC12IE5);//Enable/Start first sampling and conversion cycle/** Base address of ADC12_A Module* Start the conversion into memory buffer 0* Use the repeated sequence of channels*/ADC12_A_startConversion(ADC12_A_BASE, ADC12_A_MEMORY_4, ADC12_A_REPEATED_SEQOFCHANNELS);//Enter LPM0, Enable interrupts__bis_SR_register(LPM0_bits + GIE);//For debugger__no_operation(); }int main(void) {WDT_A_hold(WDT_A_BASE);SystemClock_Init();UART_Init(USCI_A1_BASE, 115200);ADC_Test_Init(); }#pragma vector=ADC12_VECTOR __interrupt void ADC12ISR (void) {static uint16_t index = 0;switch (__even_in_range(ADC12IV,34)){case 0: break; //Vector 0: No interruptcase 2: break; //Vector 2: ADC overflowcase 4: break; //Vector 4: ADC timing overflowcase 6: break; //Vector 6: ADC12IFG0case 8: break; //Vector 8: ADC12IFG1case 10: break; //Vector 10: ADC12IFG2case 12: break; //Vector 12: ADC12IFG3case 14: break; //Vector 14: ADC12IFG4case 16: //Vector 16: ADC12IFG5//Move A4 results, IFG is clearedA4results[index] = ADC12_A_getResults(ADC12_A_BASE, ADC12_A_MEMORY_4);//Move A5 results, IFG is clearedA5results[index] = ADC12_A_getResults(ADC12_A_BASE, ADC12_A_MEMORY_5);//Increment results index, modulo; Set BREAKPOINT hereindex++;if (index == Num_of_Results){float A4_Volt, A5_Volt;uint8_t i = 0;index = 0;for(i = 0, A4_Volt = 0; i < Num_of_Results; i++)A4_Volt += A4results[i];A4_Volt = A4_Volt/10/0xfff*3.3;for(i = 0, A5_Volt = 0; i < Num_of_Results; i++)A5_Volt += A5results[i];A5_Volt = A5_Volt/10/0xfff*3.3;UART_printf(USCI_A1_BASE, "%f, %f\r\n", A4_Volt, A5_Volt);}break;case 18: break; //Vector 18: ADC12IFG6case 20: break; //Vector 20: ADC12IFG7case 22: break; //Vector 22: ADC12IFG8case 24: break; //Vector 24: ADC12IFG9case 26: break; //Vector 26: ADC12IFG10case 28: break; //Vector 28: ADC12IFG11case 30: break; //Vector 30: ADC12IFG12case 32: break; //Vector 32: ADC12IFG13case 34: break; //Vector 34: ADC12IFG14default: break;} }#include <string.h> #include <stdarg.h> #include <stdio.h> void UART_printf(uint16_t baseAddress, const char *format,...) {uint32_t length;va_list args;uint32_t i;char TxBuffer[128] = {0};va_start(args, format);length = vsnprintf((char*)TxBuffer, sizeof(TxBuffer)+1, (char*)format, args);va_end(args);for(i = 0; i < length; i++)USCI_A_UART_transmitData(baseAddress, TxBuffer[i]); }bool UART_Init(uint16_t baseAddress, uint32_t Baudrate) {float UART_Temp = 0;USCI_A_UART_initParam huart = {0};if(baseAddress == USCI_A0_BASE) //P3.3, P3.4 = USCI_A0 TXD/RXD{GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P3, GPIO_PIN3);GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P3, GPIO_PIN4);}else if(baseAddress == USCI_A1_BASE) //P4.4, P4.5 = USCI_A1 TXD/RXD{GPIO_setAsPeripheralModuleFunctionOutputPin(GPIO_PORT_P4, GPIO_PIN4);GPIO_setAsPeripheralModuleFunctionInputPin(GPIO_PORT_P4, GPIO_PIN5);}if(Baudrate <= 9600){huart.selectClockSource = USCI_A_UART_CLOCKSOURCE_ACLK;UART_Temp = (float)UCS_getACLK()/Baudrate;}else{huart.selectClockSource = USCI_A_UART_CLOCKSOURCE_SMCLK;UART_Temp = (float)UCS_getSMCLK()/Baudrate;}if(UART_Temp < 16)huart.overSampling = USCI_A_UART_LOW_FREQUENCY_BAUDRATE_GENERATION;else{huart.overSampling = USCI_A_UART_OVERSAMPLING_BAUDRATE_GENERATION;UART_Temp /= 16;}huart.clockPrescalar = (int)UART_Temp;if(huart.overSampling == USCI_A_UART_LOW_FREQUENCY_BAUDRATE_GENERATION){huart.secondModReg = (int)((UART_Temp - huart.clockPrescalar) * 8);}else{huart.firstModReg = (int)((UART_Temp - huart.clockPrescalar) * 16);}huart.parity = USCI_A_UART_NO_PARITY;huart.msborLsbFirst = USCI_A_UART_LSB_FIRST;huart.numberofStopBits = USCI_A_UART_ONE_STOP_BIT;huart.uartMode = USCI_A_UART_MODE;if (STATUS_FAIL == USCI_A_UART_init(baseAddress, &huart)){return STATUS_FAIL;}//Enable UART module for operationUSCI_A_UART_enable(baseAddress);//Enable Receive InterruptUSCI_A_UART_clearInterrupt(baseAddress, USCI_A_UART_RECEIVE_INTERRUPT);USCI_A_UART_enableInterrupt(baseAddress, USCI_A_UART_RECEIVE_INTERRUPT);return STATUS_SUCCESS; }//****************************************************************************** // //This is the USCI_A0 interrupt vector service routine. // //****************************************************************************** #pragma vector=USCI_A0_VECTOR __interrupt void USCI_A0_ISR (void) {uint8_t receivedData = 0;switch (__even_in_range(UCA0IV,4)){//Vector 2 - RXIFGcase 2:receivedData = USCI_A_UART_receiveData(USCI_A0_BASE);USCI_A_UART_transmitData(USCI_A0_BASE,receivedData);break;default:break;} }//****************************************************************************** // //This is the USCI_A1 interrupt vector service routine. // //****************************************************************************** #pragma vector=USCI_A1_VECTOR __interrupt void USCI_A1_ISR (void) {uint8_t receivedData = 0;switch (__even_in_range(UCA1IV,4)){//Vector 2 - RXIFGcase 2:receivedData = USCI_A_UART_receiveData(USCI_A1_BASE);USCI_A_UART_transmitData(USCI_A1_BASE,receivedData);break;default:break;} }實驗結果
如圖所示，兩個通道測量值成功輸出
轉動電位器，輸出隨之變化
電壓表實測1.9864V時，打印測量值為2.003V，誤差0.8%左右
總結
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