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stm32: ADC timing rework and fixes in stm32h7_adc.c 

The stm32l412 doesn't have a PLLSAI1 clock and therefore the CKMODE
should not be set to zero.

The stm32h7 chips run the adc at 25mhz, so BOOST should be set to
0b10.

Improve timing comments.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor 2022-12-13 13:46:14 -05:00
parent cef0b70c88
commit 51526fd627
1 changed files with 23 additions and 34 deletions
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57
src/stm32/stm32h7_adc.c
View File

@ -12,21 +12,6 @@
#include "internal.h" // GPIO #include "internal.h" // GPIO
#include "sched.h" // sched_shutdown #include "sched.h" // sched_shutdown
#if CONFIG_MACH_STM32H7
#define ADC_CKMODE (0b11)
#define ADC_ATICKS (0b101)
#if CONFIG_MACH_STM32H723
#define PCSEL PCSEL_RES0
#endif
#elif CONFIG_MACH_STM32L4
#define ADC_CKMODE (0)
#define ADC_ATICKS (0b100)
#elif CONFIG_MACH_STM32G4
#define ADC_CKMODE (0b11)
#define ADC_ATICKS (0b100)
#define ADC_CCR_TSEN (ADC_CCR_VSENSESEL)
#endif
#define ADC_TEMPERATURE_PIN 0xfe #define ADC_TEMPERATURE_PIN 0xfe
DECL_ENUMERATION("pin", "ADC_TEMPERATURE", ADC_TEMPERATURE_PIN); DECL_ENUMERATION("pin", "ADC_TEMPERATURE", ADC_TEMPERATURE_PIN);
@ -169,9 +154,20 @@ static const uint8_t adc_pins[] = {
#endif #endif
}; };
// ADC timing
#define ADC_CKMODE 0b11
#define ADC_ATICKS (CONFIG_MACH_STM32H7 ? 0b101 : 0b100)
// stm32h7: clock=25Mhz, Tsamp=64.5, Tconv=71, total=2.84us
// stm32h723 adc3: clock=50Mhz, Tsamp=92.5, Tconv=105, total=2.1us
// stm32l4: clock=20Mhz, Tsamp=47.5, Tconv=60, total=3.0us
// stm32g4: clock=37.5Mhz, Tsamp=47.5, Tconv=60, total=1.6us
// ADC timing: // Handle register name differences between chips
// ADC clock=30Mhz, Tconv=6.5, Tsamp=64.5, total=2.3666us*OVERSAMPLES #if CONFIG_MACH_STM32H723
#define PCSEL PCSEL_RES0
#elif CONFIG_MACH_STM32G4
#define ADC_CCR_TSEN ADC_CCR_VSENSESEL
#endif
struct gpio_adc struct gpio_adc
gpio_adc_setup(uint32_t pin) gpio_adc_setup(uint32_t pin)
@ -185,9 +181,7 @@ gpio_adc_setup(uint32_t pin)
break; break;
} }
// Determine which ADC block to use, enable peripheral clock // Determine which ADC block to use and enable its clock
// (SYSCLK 480Mhz) /HPRE(2) /CKMODE divider(4) /additional divider(2)
// (ADC clock 30Mhz)
ADC_TypeDef *adc; ADC_TypeDef *adc;
ADC_Common_TypeDef *adc_common; ADC_Common_TypeDef *adc_common;
#ifdef ADC3 #ifdef ADC3
@ -225,9 +219,9 @@ gpio_adc_setup(uint32_t pin)
while (timer_is_before(timer_read_time(), end)) while (timer_is_before(timer_read_time(), end))
; ;
// Set Boost mode for 25Mhz < ADC clock <= 50Mhz // Set boost mode on stm32h7 (adc clock is at 25Mhz)
#ifdef ADC_CR_BOOST #ifdef ADC_CR_BOOST
MODIFY_REG(adc->CR, ADC_CR_BOOST_Msk, 0b11 << ADC_CR_BOOST_Pos); MODIFY_REG(adc->CR, ADC_CR_BOOST_Msk, 0b10 << ADC_CR_BOOST_Pos);
#endif #endif
// Calibration // Calibration
@ -250,19 +244,14 @@ gpio_adc_setup(uint32_t pin)
while(!(adc->ISR & ADC_ISR_ADRDY)) while(!(adc->ISR & ADC_ISR_ADRDY))
; ;
// Set 64.5 ADC clock cycles sample time for every channel // Set ADC clock cycles sample time for every channel
// (Reference manual pg.940)
uint32_t aticks = ADC_ATICKS; uint32_t aticks = ADC_ATICKS;
// Channel 0-9 uint32_t av = (aticks | (aticks << 3) | (aticks << 6)
adc->SMPR1 = (aticks | (aticks << 3) | (aticks << 6) | (aticks << 9) | (aticks << 12) | (aticks << 15)
| (aticks << 9) | (aticks << 12) | (aticks << 15) | (aticks << 18) | (aticks << 21) | (aticks << 24)
| (aticks << 18) | (aticks << 21) | (aticks << 24) | (aticks << 27));
| (aticks << 27)); adc->SMPR1 = av;
// Channel 10-19 adc->SMPR2 = av;
adc->SMPR2 = (aticks | (aticks << 3) | (aticks << 6)
| (aticks << 9) | (aticks << 12) | (aticks << 15)
| (aticks << 18) | (aticks << 21) | (aticks << 24)
| (aticks << 27));
// The stm32h7 chips need to be set to 12bit samples // The stm32h7 chips need to be set to 12bit samples
#if CONFIG_MACH_STM32H7 #if CONFIG_MACH_STM32H7