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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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17
hardware/sam/system/libsam/source/adc12_sam3u.c
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@@ -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;
}
/**