用示波器測試PA4腳，可測得梯形波

/******************** (C) COPYRIGHT 2008 STMicroelectronics ********************
* File Name          : readme.txt
* Author             : MCD Application Team
* Version            : V2.0
* Date               : 05/23/2008
* Description        : Description of the DAC one channel DMA escalator example.
********************************************************************************
* THE PRESENT SOFTWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
* WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE TIME.
* AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY DIRECT,
* INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING FROM THE
* CONTENT OF SUCH SOFTWARE AND/OR THE USE MADE BY CUSTOMERS OF THE CODING
* INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
* FOR MORE INFORMATION PLEASE CAREFULLY READ THE LICENSE AGREEMENT FILE LOCATED 
* IN THE ROOT DIRECTORY OF THIS FIRMWARE PACKAGE.
*******************************************************************************/

Example description
===================
This example describes how to use one DAC channel mode with DMA to generate an
escalator signal on DAC channel1 outpout.

DAC channel1 conversion is configured to be triggered by TIM6 TRGO triggers and
without noise/triangle wave generation. 8bit right data alignement is selected
since we choose to acces DAC_DHR8R1 register.
DMA2 channel3 is configured to transfer continuously, byte by byte, a 6-byte
buffer to the DAC1 register DAC_DHR8R1.

The transfered 6bytes buffer is made to have an escalator signal on DAC channel1
output. DAC channel1 is then enabled. Once TIM6 is enabled, each TIM6 TRGO update
event generate a DMA request which transfer data  to the DAC1 register and DAC
conversion is started. The escalator signal can be visualized by connecting PA.04
pin to an oscilloscope.


Directory contents
==================
stm32f10x_conf.h     Library Configuration file
stm32f10x_it.c       Interrupt handlers
stm32f10x_it.h       Header for stm32f10x_it.c
main.c               Main program


Hardware environment
====================
This example runs on STMicroelectronics STM3210E-EVAL evaluation board and can be 
easily tailored to any other hardware.

 - Connect PA.04 pin to an oscilloscope

    
How to use it
=============
In order to make the program work, you must do the following:
- Create a project and setup all your toolchain's start-up files
- Compile the directory content files and required Library files:
  + stm32f10x_lib.c
  + stm32f10x_gpio.c
  + stm32f10x_rcc.c
  + stm32f10x_nvic.c
  + stm32f10x_flash.c
  + stm32f10x_dac.c
  + stm32f10x_dma.c
  + stm32f10x_tim.c
  
- Link all compiled files and load your image into target memory
- Run the example


******************* (C) COPYRIGHT 2008 STMicroelectronics *****END OF FILE******