STM32L0开发系列——01 ADC采集
( g3 p, D; W2 E前言' N# y( w0 Z; a5 ~" b# `
使用芯片:STM32L051C8T6/ W$ z9 u: J' i( T/ @
软件平台:KEIL V5、STM32CubeL0
! [' U, U( U$ v库函数:HAL
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1 X+ h7 S8 }; d( v4 U4 y4 m, H, b一、原理图
8 Y) J8 Z: ?" n' u" v8 I本文介绍在STM32上使用ADC1的第1通道,对电池电量进行采集。
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9 b; K; ]5 i7 T二、ADC通道与引脚对应关系% m; m9 Z3 _& L; ]) H. ~4 B
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8 t' d$ [7 h) }. `6 {三、ADC相关& q3 j6 n0 r9 u' [; k
1、 ADC 可由 APB 时钟或 HSI16 时钟提供。
( {2 Z9 a. r7 M) {0 W2、 ADC 转换时间: 12 位分辨率对应的转换时间为 0.87 µs (1.14 MHz), 10 位分辨率
" i1 k' f n, g) {对应的转换时间为 0.81 µs,若降低分辨率,可进一步缩短转换时间。
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四、实验步骤
! F' \4 p' j* C+ _6 Z1、系统时钟配置: b5 o t% Q6 e$ s- l
4 m2 w% I, A& Z2 x- //******************************************************************************
: H5 m* z" Z' t( R' S, G - //name: SystemClock_Config
( |+ N! V3 T! d' j+ S - //introduce: 系统时钟配置
- ~! R6 w! I F8 k& v - //parameter: none 8 a, p. W: H( P) j) f7 j# _* U
- //return: none
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- //changetime: 2019.05.21 - {4 J! a: s1 c/ g
- //******************************************************************************
+ L/ x6 U1 v! t0 }1 } - void SystemClock_Config(void). A0 I( \; ?8 ]& M' l, C6 m6 ~% g
- {
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/ ^! ~( j0 y/ Q8 }' f& ?+ H/ q- L; U- RCC_ClkInitTypeDef RCC_ClkInitStruct;
8 J8 @* X ]* { - RCC_PeriphCLKInitTypeDef PeriphClkInit;, ^8 T2 I2 d' u# I
- RCC_OscInitTypeDef RCC_OscInitStruct;, f( t0 K: Y8 g& } j* n
6 a, b8 s& C( n [- __PWR_CLK_ENABLE();1 O* P9 h( X5 v1 M9 i/ C" T( {
5 Z6 s9 ?" |; G" {- __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
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& W* ?8 M) A L9 _6 k- RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI|RCC_OSCILLATORTYPE_HSE;
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2 U- @8 k8 ~& d- W- RCC_OscInitStruct.HSEState = RCC_HSE_ON;2 ?9 x0 R/ x7 R& O6 l& G& S
- RCC_OscInitStruct.HSIState = RCC_HSI_ON; //ADC的时钟源
/ ?4 m) @( a# T - RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;, m8 F+ Q q# y& k
- RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
1 G# s! M' p; ^- p$ Y - RCC_OscInitStruct.PLL.PLLMUL = RCC_PLLMUL_8;
& r+ F8 n$ W; Q( i - RCC_OscInitStruct.PLL.PLLDIV = RCC_PLLDIV_2;! G0 N( o% b" L4 E7 Z
- HAL_RCC_OscConfig(&RCC_OscInitStruct);
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$ z7 W4 m5 e- X' ~ R% j- RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK q- ^, i0 U7 y9 F# ~- q. w1 v
- |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;' J5 O H: z. ^! W4 }
- RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;% c% l# G4 E+ z3 U, E
- RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
6 a1 H' |3 O4 O& `% d - RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
# G; j" a% W( C1 ~8 t6 { - RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
1 A! [7 o! J8 y6 I, I+ e - HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1);5 n( u) r+ o* O: P/ |4 `
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- PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USART1;
/ u4 B3 M/ N8 a9 u4 } s8 g - PeriphClkInit.Usart1ClockSelection = RCC_USART1CLKSOURCE_PCLK2;0 m& A; f: x8 I% k( w* \: R
- HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit);
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( P' @* y4 L" C+ A- k- __SYSCFG_CLK_ENABLE();
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注意:一开始程序中没有配置HSI时钟,采集不到电压. ~* L9 y8 e, z) {* l+ M }% Z
# j' T+ X: e# R2、ADC文件
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- #include "main.h". ^) [* V, R- V
2 y& b8 f* S: ^3 F9 `4 V3 v" R! D7 r- ADC_HandleTypeDef hadc;, ?; |2 O# c: @& Z( j; H9 Y! U
- GPIO_InitTypeDef GPIO_InitStruct;& u$ t W& D) @, H
- ADC_ChannelConfTypeDef sConfig;
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5 F- M+ ]0 a0 }8 Z- //******************************************************************************
a" {6 i% S2 N# H3 n - //name: ADC_Init w8 j/ `& d) ~6 m9 O5 q$ e+ x
- //introduce: ADC初始化 1 N- z% G0 u; k
- //parameter: none
( O. W/ F$ A" q& [ - //return: none
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2 J" C, r3 n1 m3 R$ J5 C- //changetime: 2019.05.21
$ { a7 H w# Y' V3 M - //******************************************************************************
' D; U0 H3 \# m# V' A0 { i: s - void ADC_Init(void)2 ]5 x$ w& @7 x6 n3 m
- {
; Z x9 O5 |# _4 A: k8 g - uint32_t Calibration=0;
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9 m% ^2 h1 k; l) c9 c& E% }4 ` - __HAL_RCC_ADC1_CLK_ENABLE();; T' k, I3 D& y& @1 _! Z& R
- __HAL_RCC_GPIOB_CLK_ENABLE();! \! Q2 A* Q4 E4 @+ G) d
-
7 u1 H* U7 T4 K2 e3 S3 M5 H. b- L - GPIO_InitStruct.Pin = GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3;
, U; V1 ~" w) D; l8 ~# { - GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;8 _. Y/ ?" K ?: P$ m) k5 r- K) I2 k
- GPIO_InitStruct.Pull = GPIO_NOPULL;" F; M$ w. o+ X% P9 a9 m% ?
- HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);% _8 [/ |% x7 K- T( r
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- hadc.Instance = ADC1;
1 {* [7 @! `# K% U7 @) _ - hadc.Init.OversamplingMode = DISABLE;7 I( u' c- k' v
- hadc.Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV2;
- d) x. B7 r! B8 { - hadc.Init.Resolution = ADC_RESOLUTION_12B;
6 E5 F% D6 @4 K- f) ~5 Q0 q - hadc.Init.SamplingTime = ADC_SAMPLETIME_79CYCLES_5;
# [ E1 l6 S6 W z( q! K1 _ - hadc.Init.ScanConvMode = ADC_SCAN_DIRECTION_FORWARD;+ \; O. [4 l: U% w0 X: E
- hadc.Init.DataAlign = ADC_DATAALIGN_RIGHT;. Z- R: N, y* t) T& f
- hadc.Init.ContinuousConvMode = DISABLE;0 a$ j# m- E! ?
- hadc.Init.DiscontinuousConvMode = DISABLE;3 ~' f6 a& Z. t- x# S W0 X/ W
- hadc.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
, y8 E5 z0 q9 H0 a" t! a4 {/ } - hadc.Init.ExternalTrigConv = ADC_SOFTWARE_START;
' `( q6 N3 t9 G9 l6 b - hadc.Init.DMAContinuousRequests = DISABLE;
" b" q b: h3 Z; v - hadc.Init.EOCSelection = ADC_EOC_SEQ_CONV;3 _" T. O8 E4 }6 @ n: c
- hadc.Init.Overrun = ADC_OVR_DATA_PRESERVED;
9 ?: y7 |' M& m2 {8 a - hadc.Init.LowPowerAutoWait = DISABLE;
3 O; @0 j; c0 _ - hadc.Init.LowPowerFrequencyMode = DISABLE;
1 s# ^8 _( k& k/ u4 Z$ ?. b; `# { - hadc.Init.LowPowerAutoPowerOff = DISABLE;" R) F9 H) p6 d. o% q8 n
- HAL_ADC_Init(&hadc) ;
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/ s- R6 S$ q+ f0 T+ w - //启动ADC校验功能
( y0 H0 Y) V* G: i+ I( \ - HAL_ADCEx_Calibration_Start(&hadc,ADC_SINGLE_ENDED);. t5 V9 k6 Q3 P6 \
- //获取校验值& j+ I6 c9 @6 ^' ]) v
- Calibration = HAL_ADC_GetValue(&hadc);: p3 ?) B; y1 n
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- // 清除之前通道
5 z. L A" x( u8 I* n. n - sConfig.Channel = ADC_CHANNEL_1|ADC_CHANNEL_2|ADC_CHANNEL_3;
! x( a) ^5 X N! N1 X/ v - sConfig.Rank = ADC_RANK_NONE; // 清除通道属性7 |% T ?3 Q8 l
- HAL_ADC_ConfigChannel(&hadc, &sConfig);
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- //****************************************************************************** 5 ?$ [: i( n8 y, e! [
- //name: GET_ADC $ e, i, J3 Q. \9 @9 c; y I
- //introduce: 单通道采集ADC的值 - z* }$ h1 l' l; Q' b6 b, q
- //parameter: CH:ADC采集通道 + |2 H2 q' R" `/ P I- [
- //return: ADC采集值 " t8 Q+ j/ c- z2 d' v$ U% ?
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- //changetime: 2019.05.21 3 A" X) d& N4 E4 u( x
- //******************************************************************************
* n4 K+ {( M+ j9 ^ n - uint32_t GET_ADC(uint32_t CH)6 @3 E& U; w a4 N
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- uint32_t adc_conv_var;5 Z6 W+ t% c* Z1 f
- sConfig.Channel = CH;1 ?5 u9 |, q+ d6 c V% n* o- k
- sConfig.Rank = ADC_RANK_CHANNEL_NUMBER; // 设置通道! ^0 Q( U7 q$ d6 C
- HAL_ADC_ConfigChannel(&hadc, &sConfig);+ z6 x& r7 \/ S/ A/ |4 x
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- // 启动转换& m S: W+ }+ ?- a9 o2 d0 t
- HAL_ADC_Start(&hadc);
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- // 等待转换结束. H6 {/ {' G' d) |
- HAL_ADC_PollForConversion(&hadc,20);// 超时20ms
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- // 读取结果0 b) {6 q6 {8 v+ z6 `# I
- adc_conv_var = HAL_ADC_GetValue(&hadc);$ h% L, \% r. P# Z4 {
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- // 清除通道& _5 b2 ~$ [+ H/ U9 U I) @
- sConfig.Rank = ADC_RANK_NONE; // 清除通道2 i: w# l; w1 @& v9 F/ ~
- HAL_ADC_ConfigChannel(&hadc, &sConfig); d, Q# j* s0 x6 V& i- T; l
-
8 W8 e& |7 }3 A8 u - return adc_conv_var;- G" h6 B, v3 E) P" S
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* W, ~5 J3 D- ?/ E5 D& C- //****************************************************************************** + L( r0 N1 `- V% R* V$ f
- //name: Get_Adc_Average
# A+ A3 g6 Q0 ]7 P. S% i/ v$ r - //introduce: 多次采集求平均值
. H: C) E$ b, k% i - //parameter: CH:ADC采集通道
& U8 e3 r4 V3 f2 b* H) }8 C - //return: ADC采集值
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- {% a' a" d& r5 i- //changetime: 2019.05.21 ! g2 P, X" q# A) Q* N
- //******************************************************************************
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r6 O% d `! Z( U0 t1 Z- void Get_Adc_Average(uint32_t *ch,uint32_t *adcx,uint8_t times)" B+ z' q. c- z
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- uint32_t temp_val[9]={0};! T# w6 S5 D' `8 }* g; K" N
- uint8_t t,i;, P3 o9 g" }+ n& t: x8 v
- for(t=0;t<times;t++)
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( g2 J6 ~) q! l: j8 c - for(i=0;i<9;i++)
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' |+ H& A5 i3 ~( _ - temp_val<i style="font-style: italic;">+=GET_ADC(ch);2 v9 h) E9 D5 u( R. t4 |
- </i> HAL_Delay(5);! _% e7 S# u9 Q! v; J+ Y
- }
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-
1 X) o* i! x' L7 Y; k5 {& @ - for(i=0;i<9;i++)
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- adcx = temp_val/times;& u: I! @4 \; o* V
- }
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- }
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3、main中测试, y' D [, ?" N/ T) [
- while(1)
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- BATTER_VALUE = GET_ADC(ADC_CHANNEL_1);
: w. s `6 f- ]" T% @ - temp=(float)BATTER_VALUE*(3.3/4096)*2;
2 E* t8 c, v' K# i - printf("temp=%0.2f\r\n",temp);
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/ |1 ]0 q5 O. U3 l3 ]0 n - HAL_Delay(100);
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! y( V4 Z% x1 G; c* j9 ^* y四、实验结果# L ^$ _ p, _) O4 v& p* o' z: Q
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由于ADC的精度是12bit(4096)、参考电压为3.3V,因此实际读出的电量值为BATTER_VALUE3.3/40962.
# p" [8 t7 I$ p试验成功! r$ O: J P5 H* y( o
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