Arduino_Core_STM32---pinMode()实现分析
Arduino_Core_STM32—pinMode()实现分析
文章目录
- Arduino_Core_STM32---pinMode()实现分析
- pinMode()定义
- 预备知识
- `PortNames.c/h`文件解析
- `pinNames.h`文件解析
- `PinNamesTypes.h`文件解析
- `digitalPinToPinName()`函数
- `pin_function()`函数
pinMode()定义
Arduino平台的易于使用性主要就体现在屏蔽的大量底层细节的实现，对于该函数来说也不例外。虽然该函数只有两个参数（arduino引脚号和模式），但这两个参数需要多层的映射才能转化为具体适合STM32芯片的配置信息，并调用底层接口完成配置。
从下面源码中可以看出主要由两个函数来完成引脚模式配置的：digitalPinToPinName()和pinfunction()。在具体深入下面两个函数之前我们需要一些预备知识—该库对于STM32硬件端口和引脚的封装。
void pinMode(uint32_t ulPin, uint32_t ulMode)
{
PinName p = digitalPinToPinName(ulPin);
if (p != NC) {
// If the pin that support PWM or DAC output, we need to turn it off
/* 省略关闭PWM或DAC输出的代码 */
switch (ulMode) {
case INPUT: /* INPUT_FLOATING */
pin_function(p, STM_PIN_DATA(STM_MODE_INPUT, GPIO_NOPULL, 0));
break;
case INPUT_PULLUP:
pin_function(p, STM_PIN_DATA(STM_MODE_INPUT, GPIO_PULLUP, 0));
break;
case INPUT_PULLDOWN:
pin_function(p, STM_PIN_DATA(STM_MODE_INPUT, GPIO_PULLDOWN, 0));
break;
case INPUT_ANALOG:
pin_function(p, STM_PIN_DATA(STM_MODE_ANALOG, GPIO_NOPULL, 0));
break;
case OUTPUT:
pin_function(p, STM_PIN_DATA(STM_MODE_OUTPUT_PP, GPIO_NOPULL, 0));
break;
case OUTPUT_OPEN_DRAIN:
pin_function(p, STM_PIN_DATA(STM_MODE_OUTPUT_OD, GPIO_NOPULL, 0));
break;
default:
Error_Handler();
break;
}
}
}预备知识
PortNames.c/h文件解析
定义端口枚举：
typedef enum {
FirstPort = 0x00,
PortA = FirstPort,
PortB,
#if defined GPIOC_BASE
PortC,
#endif
#if defined GPIOD_BASE
PortD,
#endif
/* 省略部分定义 */
PortZ,
LastPort = PortZ - 1
} PortName;
#define MAX_NB_PORT (LastPort-FirstPort+1)
定义GPIO端口表
GPIO_TypeDef *GPIOPort[MAX_NB_PORT] = {
(GPIO_TypeDef *)GPIOA_BASE,
(GPIO_TypeDef *)GPIOB_BASE
#if defined GPIOC_BASE
, (GPIO_TypeDef *)GPIOC_BASE
#endif
#if defined GPIOD_BASE
, (GPIO_TypeDef *)GPIOD_BASE
#endif
/* 省略部分代码 */
};操作函数：返回GPIO基地址
/* Return GPIO base address */
#define get_GPIO_Port(p) ((p < MAX_NB_PORT) ? GPIOPort[p] : (GPIO_TypeDef *)NULL)pinNames.h文件解析
引脚定义：实际引脚定义中也包含的端口信息，高四位存储端口信息（PortName的枚举值），低四位存储引脚号（0-15）。
typedef enum {
// Not connected
NC = (int)0xFFFFFFFF,
// Pin name definition
PA_0 = (PortA << 4) + 0x00,
PA_1 = (PortA << 4) + 0x01,
PA_2 = (PortA << 4) + 0x02,
PA_3 = (PortA << 4) + 0x03,
PA_4 = (PortA << 4) + 0x04,
PA_5 = (PortA << 4) + 0x05,
PA_6 = (PortA << 4) + 0x06,
PA_7 = (PortA << 4) + 0x07,
PA_8 = (PortA << 4) + 0x08,
PA_9 = (PortA << 4) + 0x09,
PA_10 = (PortA << 4) + 0x0A,
PA_11 = (PortA << 4) + 0x0B,
PA_12 = (PortA << 4) + 0x0C,
PA_13 = (PortA << 4) + 0x0D,
PA_14 = (PortA << 4) + 0x0E,
PA_15 = (PortA << 4) + 0x0F,
PB_0 = (PortB << 4) + 0x00,
PB_1 = (PortB << 4) + 0x01,
PB_2 = (PortB << 4) + 0x02,
PB_3 = (PortB << 4) + 0x03,
PB_4 = (PortB << 4) + 0x04,
PB_5 = (PortB << 4) + 0x05,
PB_6 = (PortB << 4) + 0x06,
PB_7 = (PortB << 4) + 0x07,
PB_8 = (PortB << 4) + 0x08,
PB_9 = (PortB << 4) + 0x09,
PB_10 = (PortB << 4) + 0x0A,
PB_11 = (PortB << 4) + 0x0B,
PB_12 = (PortB << 4) + 0x0C,
PB_13 = (PortB << 4) + 0x0D,
PB_14 = (PortB << 4) + 0x0E,
PB_15 = (PortB << 4) + 0x0F,
#if defined GPIOC_BASE
/* 省略GPIOC的引脚定义 */
#endif
/* 省略GPIOD-GPIOJ之间的引脚定义 */
// Specific pin name
PADC_BASE = 0x100,
/* 省略部分特殊引脚的定义 */
// Specific pin name define in the variant
#if __has_include("PinNamesVar.h")
#include "PinNamesVar.h"
#endif
P_END = NC
} PinName;PinNamesTypes.h文件解析
使用在pin_function函数中的STM引脚数据，按如下32位格式的编码：
-
[2:0] Function (like in MODER reg) : Input / Output / Alt / Analog
-
[3] Output Push-Pull / Open Drain (as in OTYPER reg)
-
[5:4] as in PUPDR reg: No Pull, Pull-up, Pull-Down
-
[7:6] Reserved for speed config (as in OSPEEDR), but not used yet
-
[14:8] Alternate Num (as in AFRL/AFRG reg)
-
[19:15] Channel (Analog/Timer specific)
-
[20] Inverted (Analog/Timer specific)
-
[21] Analog ADC control - Only valid for specific families
-
[32:22] Reserved
编码信息的细节定义
#define STM_PIN_FUNCTION_MASK 0x07
#define STM_PIN_FUNCTION_SHIFT 0
#define STM_PIN_FUNCTION_BITS (STM_PIN_FUNCTION_MASK << STM_PIN_FUNCTION_SHIFT)
#define STM_PIN_OD_MASK 0x01
#define STM_PIN_OD_SHIFT 3
#define STM_PIN_OD_BITS (STM_PIN_OD_MASK << STM_PIN_OD_SHIFT)
#define STM_PIN_PUPD_MASK 0x03
#define STM_PIN_PUPD_SHIFT 4
#define STM_PIN_PUPD_BITS (STM_PIN_PUPD_MASK << STM_PIN_PUPD_SHIFT)
#define STM_PIN_SPEED_MASK 0x03
#define STM_PIN_SPEED_SHIFT 6
#define STM_PIN_SPEED_BITS (STM_PIN_SPEED_MASK << STM_PIN_SPEED_SHIFT)
#define STM_PIN_AFNUM_MASK 0x7F
#define STM_PIN_AFNUM_SHIFT 8
#define STM_PIN_AFNUM_BITS (STM_PIN_AFNUM_MASK << STM_PIN_AFNUM_SHIFT)
#define STM_PIN_CHAN_MASK 0x1F
#define STM_PIN_CHAN_SHIFT 15
#define STM_PIN_CHANNEL_BIT (STM_PIN_CHAN_MASK << STM_PIN_CHAN_SHIFT)
#define STM_PIN_INV_MASK 0x01
#define STM_PIN_INV_SHIFT 20
#define STM_PIN_INV_BIT (STM_PIN_INV_MASK << STM_PIN_INV_SHIFT)
#define STM_PIN_AN_CTRL_MASK 0x01
#define STM_PIN_AN_CTRL_SHIFT 21
#define STM_PIN_ANALOG_CONTROL_BIT (STM_PIN_AN_CTRL_MASK << STM_PIN_AN_CTRL_SHIFT)
方便从数据编码中解析出具体配置的宏函数：
#define STM_PIN_FUNCTION(X) (((X) >> STM_PIN_FUNCTION_SHIFT) & STM_PIN_FUNCTION_MASK)
#define STM_PIN_OD(X) (((X) >> STM_PIN_OD_SHIFT) & STM_PIN_OD_MASK)
#define STM_PIN_PUPD(X) (((X) >> STM_PIN_PUPD_SHIFT) & STM_PIN_PUPD_MASK)
#define STM_PIN_SPEED(X) (((X) >> STM_PIN_SPEED_SHIFT) & STM_PIN_SPEED_MASK)
#define STM_PIN_AFNUM(X) (((X) >> STM_PIN_AFNUM_SHIFT) & STM_PIN_AFNUM_MASK)
#define STM_PIN_CHANNEL(X) (((X) >> STM_PIN_CHAN_SHIFT) & STM_PIN_CHAN_MASK)
#define STM_PIN_INVERTED(X) (((X) >> STM_PIN_INV_SHIFT) & STM_PIN_INV_MASK)
#define STM_PIN_ANALOG_CONTROL(X) (((X) >> STM_PIN_AN_CTRL_SHIFT) & STM_PIN_AN_CTRL_MASK)
#define STM_PIN_MODE(X) ((STM_PIN_OD((X)) << 4) | \
(STM_PIN_FUNCTION((X)) & (~STM_PIN_OD_BITS)))
#define STM_PIN_DEFINE(FUNC_OD, PUPD, AFNUM) ((int)(FUNC_OD) |\
((PUPD & STM_PIN_PUPD_MASK) << STM_PIN_PUPD_SHIFT) |\
((AFNUM & STM_PIN_AFNUM_MASK) << STM_PIN_AFNUM_SHIFT))
#define STM_PIN_DEFINE_EXT(FUNC_OD, PUPD, AFNUM, CHAN, INV) \
((int)(FUNC_OD) |\
((PUPD & STM_PIN_PUPD_MASK) << STM_PIN_PUPD_SHIFT) |\
((AFNUM & STM_PIN_AFNUM_MASK) << STM_PIN_AFNUM_SHIFT) |\
((CHAN & STM_PIN_CHAN_MASK) << STM_PIN_CHAN_SHIFT) |\
((INV & STM_PIN_INV_MASK) << STM_PIN_INV_SHIFT))
为方便外部使用定义的宏：
/*
* MACROS to support the legacy definition of PIN formats
* The STM_MODE_ defines contain the function and the Push-pull/OpenDrain
* configuration (legacy inheritance).
*/
#define STM_PIN_DATA(FUNC_OD, PUPD, AFNUM) \
STM_PIN_DEFINE(FUNC_OD, PUPD, AFNUM)
#define STM_PIN_DATA_EXT(FUNC_OD, PUPD, AFNUM, CHANNEL, INVERTED) \
STM_PIN_DEFINE_EXT(FUNC_OD, PUPD, AFNUM, CHANNEL, INVERTED)
typedef enum {
STM_PIN_INPUT = 0,
STM_PIN_OUTPUT = 1,
STM_PIN_ALTERNATE = 2,
STM_PIN_ANALOG = 3,
} StmPinFunction;
#define STM_MODE_INPUT (STM_PIN_INPUT)
#define STM_MODE_OUTPUT_PP (STM_PIN_OUTPUT)
#define STM_MODE_OUTPUT_OD (STM_PIN_OUTPUT | STM_PIN_OD_BITS)
#define STM_MODE_AF_PP (STM_PIN_ALTERNATE)
#define STM_MODE_AF_OD (STM_PIN_ALTERNATE | STM_PIN_OD_BITS)
#define STM_MODE_ANALOG (STM_PIN_ANALOG)
#define STM_MODE_ANALOG_ADC_CONTROL (STM_PIN_ANALOG | STM_PIN_ANALOG_CONTROL_BIT)digitalPinToPinName()函数
这里我们要搞清楚几个关于引脚的概念：Arduino引脚，PinName，STM32端口和引脚。
- Arduino引脚：数字编号（0-10…）或重新定义的宏（PA1，PA2…）
- PinName：封装了STM32的端口和引脚信息
- STM32端口和引脚：具体的STM32芯片的端口（GPIOx）和引脚（GPIO_PIN_x）
宏函数：通过查表将Arduino引脚号转化为对STM32端口和引脚编码的PinName。
// Convert a digital pin number Dxx to a PinName PX_n
// Note: Analog pin is also a digital pin.
#define digitalPinToPinName(p) (((uint32_t)p < NUM_DIGITAL_PINS) ? digitalPin[p] : NC)通过下面数组可以将Arduino（Dx或x）引脚号转化为STM32的PinName（PX_n），下面具体是black_STM32F407VE板子的引脚定义（位于variants.h文件）
// Pin number
// This array allows to wrap Arduino pin number(Dx or x)
// to STM32 PinName (PX_n)
const PinName digitalPin[] = {
// Right Side
//Int //Ext
//3V3 //3V3
//3V3 //3V3
//BOOT0 //BOOT1
//GND //GND
//GND //GND
PE_1, PE_0, // D0, D1
PB_9, PB_8,
PB_7, PB_6,
PB_5, PB_3,
PD_7, PD_6,
PD_5, PD_4, // D10, D11
PD_3, PD_2,
PD_1, PD_0,
PC_12, PC_11,
PC_10, PA_15,
PA_12, PA_11, // D20, D21 PA_11: USB_DM, PA_12: USB_DP
PA_10, PA_9,
PA_8, PC_9,
PC_8, PC_7,
PC_6, PD_15,
PD_14, PD_13, // D30, D31
PD_12, PD_11,
PD_10, PD_9,
PD_8, PB_15,
// Left Side
//Ext //Int
//5V //5V
//5V //5V
//3V3 //3V3
//3V3 //3V3
//GND //GND
PE_2, PE_3,
PE_4, PE_5, // D40, D41 PE_4: BUT K0, PE_5: BUT K1
PE_6, PC_13,
PC_0, PC_1,
PC_2, PC_3,
//VREF- //VREF+
PA_0, PA_1, // PA_0(WK_UP): BUT K_UP)
PA_2, PA_3, // D50, D51
PA_4, PA_5,
/*PA_6, PA_7,*/ // PA_6, PA_7: Moved to allow contiguous analog pins
PC_4, PC_5,
PB_0, PB_1,
PA_6, PA_7, // PA_6: LED D2, PA_7: LED D3 (active LOW)
PE_7, PE_8, // D60, D61
PE_9, PE_10,
PE_11, PE_12,
PE_13, PE_14,
PE_15, PB_10,
PB_11, PB_12, // D70, D71
PB_13, PB_14,
PB_4,
};pin_function()函数
最终的配置是由该函数解析配置信息并调用底层库(LL库)函数实现的。
/**
* Configure pin (mode, speed, output type and pull-up/pull-down)
*/
void pin_function(PinName pin, int function)
{
/* Get the pin informations */
uint32_t mode = STM_PIN_FUNCTION(function);
uint32_t afnum = STM_PIN_AFNUM(function);
uint32_t port = STM_PORT(pin);
uint32_t ll_pin = STM_LL_GPIO_PIN(pin);
uint32_t ll_mode = 0;
if (pin == (PinName)NC) {
Error_Handler();
}
/* Enable GPIO clock */
GPIO_TypeDef *gpio = set_GPIO_Port_Clock(port);
/* Set default speed to high.
* For most families there are dedicated registers so it is
* not so important, register can be set at any time.
* But for families like F1, speed only applies to output.
*/
#if defined (STM32F1xx)
if (mode == STM_PIN_OUTPUT) {
#endif
#ifdef LL_GPIO_SPEED_FREQ_VERY_HIGH
LL_GPIO_SetPinSpeed(gpio, ll_pin, LL_GPIO_SPEED_FREQ_VERY_HIGH);
#else
LL_GPIO_SetPinSpeed(gpio, ll_pin, LL_GPIO_SPEED_FREQ_HIGH);
#endif
#if defined (STM32F1xx)
}
#endif
switch (mode) {
case STM_PIN_INPUT:
ll_mode = LL_GPIO_MODE_INPUT;
break;
case STM_PIN_OUTPUT:
ll_mode = LL_GPIO_MODE_OUTPUT;
break;
case STM_PIN_ALTERNATE:
ll_mode = LL_GPIO_MODE_ALTERNATE;
/* In case of ALT function, also set the afnum */
pin_SetAFPin(gpio, pin, afnum);
break;
case STM_PIN_ANALOG:
ll_mode = LL_GPIO_MODE_ANALOG;
break;
default:
Error_Handler();
break;
}
LL_GPIO_SetPinMode(gpio, ll_pin, ll_mode);
/* 省略部分代码 */
if ((mode == STM_PIN_OUTPUT) || (mode == STM_PIN_ALTERNATE)) {
if (STM_PIN_OD(function)) {
LL_GPIO_SetPinOutputType(gpio, ll_pin, LL_GPIO_OUTPUT_OPENDRAIN);
} else {
LL_GPIO_SetPinOutputType(gpio, ll_pin, LL_GPIO_OUTPUT_PUSHPULL);
}
}
pin_PullConfig(gpio, ll_pin, STM_PIN_PUPD(function));
pin_DisconnectDebug(pin);
}