Streams ADC data from pin A0 (happens to be labelled A0 on the Arduino connector of nucleo-f091rc board) More...

#include <libopencm3/cm3/cortex.h>
#include <libopencm3/cm3/nvic.h>
#include <libopencm3/stm32/adc.h>
#include <libopencm3/stm32/dac.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/timer.h>
#include <libopencm3/stm32/usart.h>
#include "arm/stm_usart.h"
#include "asc_exception.h"
#include "asc_helpers.h"
#include "ascii_serial_com.h"
#include "ascii_serial_com_device.h"
#include "ascii_serial_com_register_pointers.h"
#include "circular_buffer.h"
#include "millisec_timer.h"

Include dependency graph for stm32f091nucleo64_adc_streaming.c:

Go to the source code of this file.

Macros
#define	ASC_USART_NO 2

#define	ASC_USART USART2

#define	PORT_LED GPIOA

#define	PIN_LED GPIO5

#define	RCC_GPIO_LED RCC_GPIOA

#define	DAC_RESET_TIME_MS 500

#define	nRegs 10

#define	nChans 1

Functions
	DECLARE_ASC_DEVICE_W_REGISTER_POINTERS () static void gpio_setup(void)

static void	adc_setup (void)

static void	dac_setup (void)

int	main (void)

Variables
CEXCEPTION_T	e

uint16_t	nExceptions

	MILLISEC_TIMER_SYSTICK_IT

millisec_timer	adc_timer

uint32_t	adc_sample_period_ms = 1000

uint32_t	adc_n_overruns = 0

millisec_timer	dac_reset_timer

uint32_t	optionFlags = 0

volatile REGTYPE *	register_map [nRegs]
	Register Map.

REGTYPE	register_write_masks [nRegs]
	Write masks for register_map.

uint32_t	counter = 0

uint8_t	tmp_byte = 0

Detailed Description

Streams ADC data from pin A0 (happens to be labelled A0 on the Arduino connector of nucleo-f091rc board)

The time between ADC conversions is set in register 6, in milliseconds.

Through changing option flag, can instead stream a 32 bit counter

DAC channel 1 (A4 and Arduino A2 on board) is also enabled and may be changed by writing to register 3. Period between DAC conversions is configurable as is trinagle/noise generation.

A register write can also turn on/off the LED

Register map is documented at register_map

Definition in file stm32f091nucleo64_adc_streaming.c.

Macro Definition Documentation

◆ ASC_USART

#define ASC_USART USART2

Definition at line 40 of file stm32f091nucleo64_adc_streaming.c.

◆ ASC_USART_NO

#define ASC_USART_NO 2

Definition at line 39 of file stm32f091nucleo64_adc_streaming.c.

◆ DAC_RESET_TIME_MS

#define DAC_RESET_TIME_MS 500

Definition at line 56 of file stm32f091nucleo64_adc_streaming.c.

◆ nRegs

#define nRegs 10

Definition at line 62 of file stm32f091nucleo64_adc_streaming.c.

◆ PIN_LED

#define PIN_LED GPIO5

Definition at line 43 of file stm32f091nucleo64_adc_streaming.c.

◆ PORT_LED

#define PORT_LED GPIOA

Definition at line 42 of file stm32f091nucleo64_adc_streaming.c.

◆ RCC_GPIO_LED

#define RCC_GPIO_LED RCC_GPIOA

Definition at line 44 of file stm32f091nucleo64_adc_streaming.c.

Function Documentation

◆ adc_setup()

static void adc_setup ( void )

static

Definition at line 165 of file stm32f091nucleo64_adc_streaming.c.

◆ dac_setup()

static void dac_setup ( void )

static

Definition at line 195 of file stm32f091nucleo64_adc_streaming.c.

◆ DECLARE_ASC_DEVICE_W_REGISTER_POINTERS()

DECLARE_ASC_DEVICE_W_REGISTER_POINTERS ( )

Definition at line 155 of file stm32f091nucleo64_adc_streaming.c.

◆ main()

int main ( void )

Definition at line 223 of file stm32f091nucleo64_adc_streaming.c.

Variable Documentation

◆ adc_n_overruns

uint32_t adc_n_overruns = 0

Definition at line 54 of file stm32f091nucleo64_adc_streaming.c.

◆ adc_sample_period_ms

uint32_t adc_sample_period_ms = 1000

Definition at line 53 of file stm32f091nucleo64_adc_streaming.c.

◆ adc_timer

millisec_timer adc_timer

Definition at line 52 of file stm32f091nucleo64_adc_streaming.c.

◆ counter

uint32_t counter = 0

Definition at line 153 of file stm32f091nucleo64_adc_streaming.c.

◆ dac_reset_timer

millisec_timer dac_reset_timer

Definition at line 55 of file stm32f091nucleo64_adc_streaming.c.

◆ e

CEXCEPTION_T e

Definition at line 48 of file stm32f091nucleo64_adc_streaming.c.

◆ MILLISEC_TIMER_SYSTICK_IT

MILLISEC_TIMER_SYSTICK_IT

Definition at line 51 of file stm32f091nucleo64_adc_streaming.c.

◆ nExceptions

uint16_t nExceptions

Definition at line 49 of file stm32f091nucleo64_adc_streaming.c.

◆ optionFlags

uint32_t optionFlags = 0

Definition at line 60 of file stm32f091nucleo64_adc_streaming.c.

◆ register_map

volatile REGTYPE* register_map[nRegs]

Initial value:

= {
    &GPIOA_IDR, 
    &GPIOA_ODR, 
    &optionFlags,
    &DAC_DHR12R1(DAC1),    
    &DAC_DHR12R2(DAC1),    
    &MILLISEC_TIMER_NOW,   
    &adc_sample_period_ms, 
    &adc_n_overruns,       
    &TIM_ARR(TIM6),        
    &DAC_CR(DAC1), 
                   
}

Register Map.

Register Map

Register Number	Description	r/w
0	PORTA input data register, bit 5 is LED	r
1	PORTA output data register, bit 5 is LED	r, bit 5 is w
2	optionFlags: see below	r/w
3	DAC Channel 1 output val	r, bottom 12 bits w
4	Reserved for DAC Channel 2, but not implemented	r
5	Current millisecond_timer value	r
6	Period between ADC samples in ms *	r/w
7	Number of times ADC overrun flag has been set	r
8	Time between DAC conversion in 100 us *	r/w 16 bits
9	DAC waveform & waveform amplitude sel. *	r, w bits 6-10

Option flags

Big Number	Description
0	if 0: stream ADC, if 1: stream counter
1	if 1: disable & re-enable DAC, then reset bit to 0, if 0: nothing

Register 6: ADC sample period only written to ADC register when 'n' command received

Register 8: default 100, so update every 10 ms

Waveform generation with register 9

Register 9: default 0. Bits 6-7 (start from 0) control waveform generation. 00: disabled, 01: noise, 1x: triangle. Bits 8-11 are amplitude: where the max-min is 2^(n+1)-1, where n is the value (at least for triangle), maxing out at 0b1011=0xB. The triangle starts from reg 3 and goes up to the max-min value programmed, then comes back down. The noise is centered around register 3.

So, write to the register: 0xYZ0, where Y is the amplitude: 0-B, and Z is the waveform type: 0 for none, 1 for nosie, 8 for triangle.

I'd say the noise has an RMS in the region of 10 counts. The mask doesn't change the RMS that much.

It may be necessary to reset the DAC (see option flags) to change the amplitude and/or disable waveform generation

Register 9 examples:

triangle with max-min = 127: 0b10110000000 = 0x680
full scale triangle: write 9 0xB80, write 3 0, write 8 3
noise with large amplitude: 0xB10
flat, waveform disabled: 0

See also: register_write_masks

Definition at line 121 of file stm32f091nucleo64_adc_streaming.c.

◆ register_write_masks

REGTYPE register_write_masks[nRegs]