這段程序完成了DMA1通道的配置，首先定義了DMA_InitType DMA_InitStructure，接著配置DMA_InitType的各種參數(shù)，各參數(shù)的命名方式也均使用約定的命名方式，從命名就能夠很容易的看出各參數(shù)所指代的具體功能。功能參數(shù)配置完成后，使用DMA_Init(DMA1_Channel1, &DMA_InitStructure);完成相應(yīng)外設(shè)的初始化，最后使用DMA_Cmd(DMA1_Channel1, ENABLE) 使能相應(yīng)外設(shè)。從這個例子就能夠很容易的看出標(biāo)準(zhǔn)外設(shè)庫這種規(guī)范化的命名規(guī)則給編寫和閱讀程序帶來的好處。

3. 變量定義

在早期的版本中有24個變量定義，在Keil的安裝根目錄下，可以找到對應(yīng)的定義，路徑為：Keil\ARM\INC\ST\STM32F10x\stm32f10x_type.h

1 /* Includes ------------------------------------------------------------------*/ 2 3 /* Exported types ------------------------------------------------------------*/ 4 5 typedef signed long s32; 6 7 typedef signed short s16; 8 9 typedef signed char s8; 10 11 typedef signed long const sc32; /* Read Only */ 12 13 typedef signed short const sc16; /* Read Only */ 14 15 typedef signed char const sc8; /* Read Only */ 16 17 typedef volatile signed long vs32; 18 19 typedef volatile signed short vs16; 20 21 typedef volatile signed char vs8; 22 23 typedef volatile signed long const vsc32; /* Read Only */ 24 25 typedef volatile signed short const vsc16; /* Read Only */ 26 27 typedef volatile signed char const vsc8; /* Read Only */ 28 29 typedef unsigned long u32; 30 31 typedef unsigned short u16; 32 33 typedef unsigned char u8; 34 35 typedef unsigned long const uc32; /* Read Only */ 36 37 typedef unsigned short const uc16; /* Read Only */ 38 39 typedef unsigned char const uc8; /* Read Only */ 40 41 typedef volatile unsigned long vu32; 42 43 typedef volatile unsigned short vu16; 44 45 typedef volatile unsigned char vu8; 46 47 typedef volatile unsigned long const vuc32; /* Read Only */ 48 49 typedef volatile unsigned short const vuc16; /* Read Only */ 50 51 typedef volatile unsigned char const vuc8; /* Read Only */