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Diffstat (limited to 'libopencm3/lib/stm32/f4/adc.c')
| -rw-r--r-- | libopencm3/lib/stm32/f4/adc.c | 437 |
1 files changed, 437 insertions, 0 deletions
diff --git a/libopencm3/lib/stm32/f4/adc.c b/libopencm3/lib/stm32/f4/adc.c new file mode 100644 index 0000000..fba88de --- /dev/null +++ b/libopencm3/lib/stm32/f4/adc.c @@ -0,0 +1,437 @@ +/** @defgroup adc_file ADC + +@ingroup STM32F4xx + +@brief <b>libopencm3 STM32F4xx Analog to Digital Converters</b> + +@author @htmlonly © @endhtmlonly 2012 +Ken Sarkies <ksarkies@internode.on.net> + +@date 30 August 2012 + +This library supports the A/D Converter Control System in the STM32 series +of ARM Cortex Microcontrollers by ST Microelectronics. + +Devices can have up to three A/D converters each with their own set of +registers. However all the A/D converters share a common clock which is +prescaled from the APB2 clock by default by a minimum factor of 2 to a maximum +of 8. The ADC resolution can be set to 12, 10, 8 or 6 bits. + +Each A/D converter has up to 19 channels: +@li On ADC1 the analog channels 16 is internally connected to the temperature +sensor, channel 17 to V<sub>REFINT</sub>, and channel 18 to V<sub>BATT</sub>. +@li On ADC2 and ADC3 the analog channels 16 - 18 are not used. + +The conversions can occur as a one-off conversion whereby the process stops +once conversion is complete. The conversions can also be continuous wherein a +new conversion starts immediately the previous conversion has ended. + +Conversion can occur as a single channel conversion or a scan of a group of +channels in either continuous or one-off mode. If more than one channel is +converted in a scan group, DMA must be used to transfer the data as there is +only one result register available. An interrupt can be set to occur at the end +of conversion, which occurs after all channels have been scanned. + +A discontinuous mode allows a subgroup of group of a channels to be converted +in bursts of a given length. + +Injected conversions allow a second group of channels to be converted +separately from the regular group. An interrupt can be set to occur at the end +of conversion, which occurs after all channels have been scanned. + +@section adc_f4_api_ex Basic ADC Handling API. + +Example 1: Simple single channel conversion polled. Enable the peripheral clock +and ADC, reset ADC and set the prescaler divider. Set multiple mode to +independent. + +@code +gpio_mode_setup(GPIOA, GPIO_MODE_ANALOG, GPIO_PUPD_NONE, GPIO1); +rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_ADC1EN); +adc_set_clk_prescale(RCC_CFGR_ADCPRE_BY2); +adc_disable_scan_mode(ADC1); +adc_set_single_conversion_mode(ADC1); +adc_set_sample_time(ADC1, ADC_CHANNEL0, ADC_SMPR1_SMP_1DOT5CYC); +uint8_t channels[] = ADC_CHANNEL0; +adc_set_regular_sequence(ADC1, 1, channels); +adc_set_multi_mode(ADC_CCR_MULTI_INDEPENDENT); +adc_power_on(ADC1); +adc_start_conversion_regular(ADC1); +while (! adc_eoc(ADC1)); +reg16 = adc_read_regular(ADC1); +@endcode + +LGPL License Terms @ref lgpl_license + */ +/* + * This file is part of the libopencm3 project. + * + * Copyright (C) 2012 Ken Sarkies <ksarkies@internode.on.net> + * + * This library is free software: you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this library. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <libopencm3/stm32/adc.h> + +/**@{*/ + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Set the Sample Time for a Single Channel + +The sampling time can be selected in ADC clock cycles from 1.5 to 239.5. + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +@param[in] channel Unsigned int8. ADC Channel integer 0..18 or from @ref +adc_channel +@param[in] time Unsigned int8. Sampling time selection from @ref adc_sample_rg + * NOTE Common with f1, f2 and f37x +*/ + +void adc_set_sample_time(uint32_t adc, uint8_t channel, uint8_t time) +{ + uint32_t reg32; + + if (channel < 10) { + reg32 = ADC_SMPR2(adc); + reg32 &= ~(0x7 << (channel * 3)); + reg32 |= (time << (channel * 3)); + ADC_SMPR2(adc) = reg32; + } else { + reg32 = ADC_SMPR1(adc); + reg32 &= ~(0x7 << ((channel - 10) * 3)); + reg32 |= (time << ((channel - 10) * 3)); + ADC_SMPR1(adc) = reg32; + } +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Set the Sample Time for All Channels + +The sampling time can be selected in ADC clock cycles from 1.5 to 239.5, same +for all channels. + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +@param[in] time Unsigned int8. Sampling time selection from @ref adc_sample_rg + * NOTE Common with f1, f2 and f37x +*/ + +void adc_set_sample_time_on_all_channels(uint32_t adc, uint8_t time) +{ + uint8_t i; + uint32_t reg32 = 0; + + for (i = 0; i <= 9; i++) { + reg32 |= (time << (i * 3)); + } + ADC_SMPR2(adc) = reg32; + + for (i = 10; i <= 17; i++) { + reg32 |= (time << ((i - 10) * 3)); + } + ADC_SMPR1(adc) = reg32; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Power On + +If the ADC is in power-down mode then it is powered up. The application needs +to wait a time of about 3 microseconds for stabilization before using the ADC. +If the ADC is already on this function call will have no effect. + * NOTE Common with L1 and F2 + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +*/ + +void adc_power_on(uint32_t adc) +{ + ADC_CR2(adc) |= ADC_CR2_ADON; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Set Clock Prescale + +The ADC clock taken from the APB2 clock can be scaled down by 2, 4, 6 or 8. + +@param[in] prescale Unsigned int32. Prescale value for ADC Clock @ref +adc_ccr_adcpre +*/ + +void adc_set_clk_prescale(uint32_t prescale) +{ + uint32_t reg32 = ((ADC_CCR & ~ADC_CCR_ADCPRE_MASK) | prescale); + ADC_CCR = reg32; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Set Dual/Triple Mode + +The multiple mode uses ADC1 as master, ADC2 and optionally ADC3 in a slave +arrangement. This setting is applied to ADC1 only. + +The various modes possible are described in the reference manual. + +@param[in] mode Unsigned int32. Multiple mode selection from @ref adc_multi_mode +*/ + +void adc_set_multi_mode(uint32_t mode) +{ + ADC_CCR |= mode; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Enable an External Trigger for Regular Channels + +This enables an external trigger for set of defined regular channels, and sets +the polarity of the trigger event: rising or falling edge or both. Note that if +the trigger polarity is zero, triggering is disabled. + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +@param[in] trigger Unsigned int32. Trigger identifier @ref adc_trigger_regular +@param[in] polarity Unsigned int32. Trigger polarity @ref +adc_trigger_polarity_regular +*/ + +void adc_enable_external_trigger_regular(uint32_t adc, uint32_t trigger, + uint32_t polarity) +{ + uint32_t reg32 = ADC_CR2(adc); + + reg32 &= ~(ADC_CR2_EXTSEL_MASK | ADC_CR2_EXTEN_MASK); + reg32 |= (trigger | polarity); + ADC_CR2(adc) = reg32; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Disable an External Trigger for Regular Channels + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +*/ + +void adc_disable_external_trigger_regular(uint32_t adc) +{ + ADC_CR2(adc) &= ~ADC_CR2_EXTEN_MASK; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Enable an External Trigger for Injected Channels + +This enables an external trigger for set of defined injected channels, and sets +the polarity of the trigger event: rising or falling edge or both. + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +@param[in] trigger Unsigned int8. Trigger identifier @ref adc_trigger_injected +@param[in] polarity Unsigned int32. Trigger polarity @ref +adc_trigger_polarity_injected +*/ + +void adc_enable_external_trigger_injected(uint32_t adc, uint32_t trigger, + uint32_t polarity) +{ + uint32_t reg32 = ADC_CR2(adc); + + reg32 &= ~(ADC_CR2_JEXTSEL_MASK | ADC_CR2_JEXTEN_MASK); + reg32 |= (trigger | polarity); + ADC_CR2(adc) = reg32; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Disable an External Trigger for Injected Channels + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +*/ + +void adc_disable_external_trigger_injected(uint32_t adc) +{ + ADC_CR2(adc) &= ~ADC_CR2_JEXTEN_MASK; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Set Resolution + +ADC Resolution can be reduced from 12 bits to 10, 8 or 6 bits for a +corresponding reduction in conversion time (resolution + 3 ADC clock cycles). + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +@param[in] resolution Unsigned int32. Resolution value @ref adc_cr1_res +*/ + +void adc_set_resolution(uint32_t adc, uint32_t resolution) +{ + uint32_t reg32 = ADC_CR1(adc); + + reg32 &= ~ADC_CR1_RES_MASK; + reg32 |= resolution; + ADC_CR1(adc) = reg32; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Enable the Overrun Interrupt + +The overrun interrupt is generated when data is not read from a result register +before the next conversion is written. If DMA is enabled, all transfers are +terminated and any conversion sequence is aborted. + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +*/ + +void adc_enable_overrun_interrupt(uint32_t adc) +{ + ADC_CR1(adc) |= ADC_CR1_OVRIE; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Disable the Overrun Interrupt + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +*/ + +void adc_disable_overrun_interrupt(uint32_t adc) +{ + ADC_CR1(adc) &= ~ADC_CR1_OVRIE; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Read the Overrun Flag + +The overrun flag is set when data is not read from a result register before the +next conversion is written. If DMA is enabled, all transfers are terminated and +any conversion sequence is aborted. + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +@returns Unsigned int32 conversion result. +*/ + +bool adc_get_overrun_flag(uint32_t adc) +{ + return ADC_SR(adc) & ADC_SR_OVR; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Clear Overrun Flags + +The overrun flag is cleared. Note that if an overrun occurs, DMA is terminated. +The flag must be cleared and the DMA stream and ADC reinitialised to resume +conversions (see the reference manual). + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +@returns Unsigned int32 conversion result. +*/ + +void adc_clear_overrun_flag(uint32_t adc) +{ +/* need to write zero to clear this */ + ADC_SR(adc) &= ~ADC_SR_OVR; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Enable an EOC for Each Conversion + +The EOC is set after each conversion in a sequence rather than at the end of the +sequence. Overrun detection is enabled only if DMA is enabled. + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +*/ + +void adc_eoc_after_each(uint32_t adc) +{ + ADC_CR2(adc) |= ADC_CR2_EOCS; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Disable the EOC for Each Conversion + +The EOC is set at the end of each sequence rather than after each conversion in +the sequence. Overrun detection is enabled always. + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +*/ + +void adc_eoc_after_group(uint32_t adc) +{ + ADC_CR2(adc) &= ~ADC_CR2_EOCS; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Set DMA to Continue + +This must be set to allow DMA to continue to operate after the last conversion +in the DMA sequence. This allows DMA to be used in continuous circular mode. + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +*/ + +void adc_set_dma_continue(uint32_t adc) +{ + ADC_CR2(adc) |= ADC_CR2_DDS; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Set DMA to Terminate + +This must be set to allow DMA to terminate after the last conversion in the DMA +sequence. This can avoid overrun errors. + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +*/ + +void adc_set_dma_terminate(uint32_t adc) +{ + ADC_CR2(adc) &= ~ADC_CR2_DDS; +} +/*---------------------------------------------------------------------------*/ +/** @brief ADC Read the Analog Watchdog Flag + +This flag is set when the converted voltage crosses the high or low thresholds. + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +@returns bool. AWD flag. +*/ + +bool adc_awd(uint32_t adc) +{ + return ADC_SR(adc) & ADC_SR_AWD; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Enable The Temperature Sensor + +This enables both the sensor and the reference voltage measurements on channels +16 and 17. These are only available on ADC1 channel 16 and 17 respectively. + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +*/ + +void adc_enable_temperature_sensor() +{ + ADC_CCR |= ADC_CCR_TSVREFE; +} + +/*---------------------------------------------------------------------------*/ +/** @brief ADC Disable The Temperature Sensor + +Disabling this will reduce power consumption from the sensor and the reference +voltage measurements. + +@param[in] adc Unsigned int32. ADC block register address base @ref adc_reg_base +*/ + +void adc_disable_temperature_sensor() +{ + ADC_CCR &= ~ADC_CCR_TSVREFE; +} + +/*---------------------------------------------------------------------------*/ + +/**@}*/ + |