工作中有时候用到需要对PWM波形进行频率和周期的变化，利用DMA Brust时一个比较好的选择，将ST提供的基于F3的例程改到基于F103实现，没什么难度，但是调试的时候最先使用Normal模式导致不宜观察，后改为Circular模式。代码如下：
void TIM1_Init()
{
GPIO_InitTypeDef         GPIO_InitStructure;
DMA_InitTypeDef          DMA_InitStructure;
; S6 ]/ a; X0 ?. _. FTIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
8 Z9 `: H2 L$ nTIM_OCInitTypeDef        TIM_OCInitStructure;
( F7 d- `- }4 R+ G4 Y0 L2 I  uint16_t SRC_Buffer[9] = {4000-1,1,800,10000-1,0,8500,4000-1,2,2000};
  /* TIM1 and GPIOA clock enable */
# T, Q' b% j+ Z  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 | RCC_APB2Periph_GPIOA, ENABLE);

  /* DMA clock enable */
6 \+ k/ P* k) N2 i$ w! \) J  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
  
  /* GPIOA Configuration: Channel 1 as alternate function push-pull */
  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_8;
# U: s. y9 V  _9 [" p8 a  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
/ a  h; r0 V$ A% T2 e) D3 o  v7 h  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);  
2 B# f2 @  f" w8 P$ X
0 }! d. P- @6 m& k' a  /* TIM1 DeInit */
. M1 U8 Q+ G" O+ s! ^: U0 M  TIM_DeInit(TIM1);
' v" x( h/ ~/ r5 h/ x8 z
, E. R+ V5 P) I" i* P  /* DMA1 Channel5 Config */
5 Q% w- t# I! T/ J  DMA_DeInit(DMA1_Channel5);

2 L  {# s( W( W, b  y) Z  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)TIM1_DMAR_ADDRESS;
  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)SRC_Buffer;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
! n) E% S& \& u2 I  DMA_InitStructure.DMA_BufferSize = 18;
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
, U( a5 t; E2 z6 E, S  DMA_InitStructure.DMA_Priority = DMA_Priority_High;
4 a! h- {* T; D; X7 L  DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
, [/ N. p4 m9 C; v' G  DMA_Init(DMA1_Channel5, &DMA_InitStructure);
4 w9 B: {8 v4 P2 C& W' s  
  /* Time base configuration */
3 `8 x0 C* X8 a- f7 o2 b& R  /* -----------------------------------------------------------------------
( P, A: \2 h, F) C4 A, U    TIM1 Configuration: generate 1 PWM signal using the DMA burst mode:
- K  D' z* P3 u, o    The TIM1CLK frequency is set to SystemCoreClock (Hz), to get TIM1 counter
) X/ d  a$ r  Y; j' r    clock at 24 MHz the Prescaler is computed as following:
     - Prescaler = (TIM1CLK / TIM1 counter clock) - 1
+ m. T2 d' w( D2 ^" N" Q3 t/ ^1 n* a; M    SystemCoreClock is set to 72 MHz for Low-density, Medium-density, High-density
    and Connectivity line devices and to 24 MHz for Low-Density Value line and
    Medium-Density Value line devices

' N: K5 H. V% e4 ?2 q2 P: {  F    The TIM1 period is 5.8 KHz: TIM1 Frequency = TIM1 counter clock/(ARR + 1)
' r/ L! f4 i4 D' q                                               = 24 MHz / 4096 = 5.8KHz KHz
* `' b4 }0 |. g$ T    TIM1 Channel1 duty cycle = (TIM1_CCR1/ TIM1_ARR)* 100 = 33.33%
, l1 |: _: f( a/ `' v" I7 d5 _2 l  ----------------------------------------------------------------------- */  
, }3 E5 e. B; M2 g+ ?* n/ Q, |  TIM_TimeBaseStructure.TIM_Period = 0xFFFF;         
6 S+ f& P7 _( l* Z4 D" {  G4 _8 Y  TIM_TimeBaseStructure.TIM_Prescaler = (uint16_t) (SystemCoreClock / 24000000) - 1;      
  TIM_TimeBaseStructure.TIM_ClockDivision = 0x0;   
/ O) @+ c/ ^" _& \$ O  U( c  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;   
, C0 V& s9 ]. W) Z: f  TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);

+ ~3 z7 h  n; C3 B2 ~; j  /* TIM Configuration in PWM Mode */
) j2 _% m4 C/ Z  TIM_OCInitStructure.TIM_OCMode =  TIM_OCMode_PWM1;   
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;         
8 T* q9 H9 o- ~  TIM_OCInitStructure.TIM_Pulse = 0xFFF;  
  TIM_OC1Init(TIM1, &TIM_OCInitStructure);
& q7 ^. J4 ~+ p( l1 N" ^) n
  /* TIM1 DMAR Base register and DMA Burst Length Config */
7 F% v6 ^  C6 X5 C3 y  TIM_DMAConfig(TIM1, TIM_DMABase_ARR, TIM_DMABurstLength_6Transfers);

/ z, f$ k- D  e6 @0 s7 c  /* TIM1 DMA Update enable */
* l) }( g) u# y. T/ ~7 t  TIM_DMACmd(TIM1, TIM_DMA_Update, ENABLE);

9 R2 z, B, j' W2 [6 G& E5 C  /* TIM1 enable */
  TIM_Cmd(TIM1, ENABLE);
  
. A  I* ?7 @# _& Y& l  /* TIM1 PWM Outputs Enable */
  TIM_CtrlPWMOutputs(TIM1, ENABLE);
9 @* u  ?6 R0 }1 \
  /* DMA1 Channel5 enable */
  DMA_Cmd(DMA1_Channel5, ENABLE);
# [$ i' H( }7 z
7 @4 u2 [( ?' J( b% M  /* Wait until DMA1 Channel5 end of Transfer */
  while (!DMA_GetFlagStatus(DMA1_FLAG_TC5))
) o) B0 P3 f) ~  {
/ I* \% y9 U5 \  }
" Q) r) J$ z2 g6 c}

调试时遇到一个问题，在TIM1-CH1测试通过，但是改成TIM8-CH1的时候却不行，有波形输出但是频率、周期不变，求赐教。

TIM8使用TIM_DMACmd(TIM8, TIM_DMA_CC1, ENABLE);测试OK。

我现在自己只会产生一个pwm波，还不会精确控制波形个数。我想问一下有没有完整的工程文件，我是初学者，想修改修改能用的。