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Code Issues Releases Activity

Fixed 'shaking' readings from ADC/ADC12

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This commit is contained in:
Cristian Maglie 2011-11-27 19:15:33 +01:00
parent b853464da8
commit 037ecd3e3e
4 changed files with 30 additions and 18 deletions
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11
hardware/sam/system/libsam/include/adc.h
View File

@ -43,11 +43,14 @@
#include "../chip.h"
#define ADC_FREQ_MAX 20000000
#define ADC_FREQ_MIN 1000000
#define ADC_FREQ_MAX 5000000
#define ADC_STARTUP 20
#define ADC_STARTUP_NORM 40
#define ADC_STARTUP_FAST 12
#define ADC12_FREQ_MAX 20000000
#define ADC12_FREQ_MIN 1000000
#define ADC12_STARTUP_NORM 40
#define ADC12_STARTUP_FAST 12
/* Definitions for ADC resolution */
typedef enum _adc_resolution_t {

12
hardware/sam/system/libsam/source/adc10_sam3u.c
View File

@ -64,7 +64,6 @@ extern "C" {
*/
uint32_t adc_init(Adc *p_adc, uint32_t ul_mck, uint32_t ul_adc_clock, uint32_t ul_startuptime)
{
uint32_t ul_prescal,ul_startup;
p_adc->ADC_CR = ADC_CR_SWRST;
/* Reset Mode Register */
@ -76,9 +75,14 @@ uint32_t adc_init(Adc *p_adc, uint32_t ul_mck, uint32_t ul_adc_clock, uint32_t u
p_adc->ADC_RNCR = 0;
p_adc->ADC_TCR = 0;
p_adc->ADC_TNCR = 0;
ul_prescal = ul_mck/(2 * ul_adc_clock) - 1;
ul_startup = ((ul_adc_clock/1000000) * ul_startuptime / 8) - 1;
p_adc->ADC_MR |= ADC_MR_PRESCAL( ul_prescal ) | ( (ul_startup<<ADC_MR_STARTUP_Pos) & ADC_MR_STARTUP_Msk);
uint32_t prescal = ul_mck/(2 * ul_adc_clock) - 1;
// check for rounding errors
if ( (ul_mck/((prescal+1)*2)) > ul_adc_clock ) {
prescal++;
ul_adc_clock = ul_mck/((prescal+1)*2);
}
uint32_t startup = ((ul_adc_clock/1000000) * ul_startuptime / 8) - 1;
p_adc->ADC_MR |= ADC_MR_PRESCAL(prescal) | ADC_MR_STARTUP(startup);
return 0;
}

17
hardware/sam/system/libsam/source/adc12_sam3u.c
View File

@ -64,7 +64,6 @@ extern "C" {
*/
uint32_t adc12_init(Adc12b *p_adc, uint32_t ul_mck, uint32_t ul_adc_clock, uint32_t ul_startuptime, uint32_t ul_offmode_startuptime)
{
uint32_t ul_prescal,ul_startup,ul_offmode;
p_adc->ADC12B_CR = ADC12B_CR_SWRST;
/* Reset Mode Register */
@ -76,11 +75,17 @@ uint32_t adc12_init(Adc12b *p_adc, uint32_t ul_mck, uint32_t ul_adc_clock, uint3
p_adc->ADC12B_RNCR = 0;
p_adc->ADC12B_TCR = 0;
p_adc->ADC12B_TNCR = 0;
ul_prescal = ul_mck/(2 * ul_adc_clock) - 1;
ul_startup = ((ul_adc_clock/1000000) * ul_startuptime / 8) - 1;
ul_offmode = ((ul_adc_clock/1000000) * ul_offmode_startuptime / 8) - 1;
p_adc->ADC12B_MR |= ADC12B_MR_PRESCAL( ul_prescal ) | ( (ul_startup<<ADC12B_MR_STARTUP_Pos) & ADC12B_MR_STARTUP_Msk);
p_adc->ADC12B_EMR |= (ul_offmode<<16) & (0xffu << 16);
uint32_t prescal = ul_mck/(2 * ul_adc_clock) - 1;
// check for rounding errors
if ( (ul_mck/((prescal+1)*2)) > ul_adc_clock ) {
prescal++;
ul_adc_clock = ul_mck/((prescal+1)*2);
}
uint32_t startup = ((ul_adc_clock/1000000) * ul_startuptime / 8) - 1;
p_adc->ADC12B_MR |= ADC12B_MR_PRESCAL(prescal) | ADC12B_MR_STARTUP(startup);
uint32_t offmode = ((ul_adc_clock/1000000) * ul_offmode_startuptime / 8) - 1;
p_adc->ADC12B_EMR |= ADC12B_EMR_OFF_MODE_STARTUP_TIME(offmode);
return 0;
}
/**

8
hardware/sam/variants/arduino_due/variant.cpp
View File

@ -350,8 +350,8 @@ extern void init( void )
* prescal: ADCClock = MCK / ( (PRESCAL+1) * 2 ) => 64MHz / ((4+1)*2) = 6.4MHz
* ADC clock = 6.4 MHz
*/
adc_init( ADC, SystemCoreClock, 6400000, 10 ) ;
adc_configure_timing( ADC, 1200 ) ;
adc_init( ADC, SystemCoreClock, ADC_FREQ_MAX, ADC_STARTUP ) ;
adc_configure_timing( ADC, 15 ) ;
adc_configure_trigger( ADC, ADC_TRIG_SW ) ;
adc_disable_interrupt( ADC, 0xFFFFFFFF ) ; /* Disable all adc interrupt. */
adc_disable_channel( ADC, ADC_ALL_CHANNEL ) ;
@ -366,8 +366,8 @@ extern void init( void )
* prescal: ADCClock = MCK / ( (PRESCAL+1) * 2 ) => 64MHz / ((4+1)*2) = 6.4MHz
* ADC clock = 6.4 MHz
*/
adc12_init( ADC12B, SystemCoreClock, 6400000, 10, 1200 ) ;
adc12_configure_timing( ADC12B, 1200 ) ;
adc12_init( ADC12B, SystemCoreClock, ADC12_FREQ_MAX, ADC12_STARTUP_FAST, 1 ) ;
adc12_configure_timing( ADC12B, 15 ) ;
adc12_configure_trigger( ADC12B, ADC_TRIG_SW ) ;
adc12_disable_interrupt( ADC12B, 0xFFFFFFFF ) ; /* Disable all adc interrupt. */
adc12_disable_channel( ADC12B, ADC_ALL_CHANNEL ) ;