DSP281x_Adc.c
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上传日期:2014-10-27
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- //###########################################################################
- //
- // FILE: DSP281x_Adc.c
- //
- // TITLE: DSP281x ADC Initialization & Support Functions.
- //
- //###########################################################################
- //
- // Ver | dd mmm yyyy | Who | Description of changes
- // =====|=============|======|===============================================
- // 1.00| 11 Sep 2003 | L.H. | Changes since previous version (v.58 Alpha)
- // | | | ADC_usDELAY changed from 5000L to 8000L
- //###########################################################################
- #include "DSP281x_Device.h" // DSP281x Headerfile Include File
- #include "DSP281x_Examples.h" // DSP281x Examples Include File
- #define ADC_usDELAY 8000L
- #define ADC_usDELAY2 20L
- //---------------------------------------------------------------------------
- // InitAdc:
- //---------------------------------------------------------------------------
- // This function initializes ADC to a known state.
- //
- void InitAdc(void)
- {
- extern void DSP28x_usDelay(Uint32 Count);
-
- // To powerup the ADC the ADCENCLK bit should be set first to enable
- // clocks, followed by powering up the bandgap and reference circuitry.
- // After a 5ms delay the rest of the ADC can be powered up. After ADC
- // powerup, another 20us delay is required before performing the first
- // ADC conversion. Please note that for the delay function below to
- // operate correctly the CPU_CLOCK_SPEED define statement in the
- // DSP28_Examples.h file must contain the correct CPU clock period in
- // nanoseconds. For example:
- AdcRegs.ADCTRL3.bit.ADCBGRFDN = 0x3; // Power up bandgap/reference circuitry
- DELAY_US(ADC_usDELAY); // Delay before powering up rest of ADC
- AdcRegs.ADCTRL3.bit.ADCPWDN = 1; // Power up rest of ADC
- DELAY_US(ADC_usDELAY2); // Delay after powering up ADC
- }
- //===========================================================================
- // No more.
- //===========================================================================