http://www.efton.sk/STM32/bt.c // Timer-triggered memory-to-memory DMA transfer demonstrator for STM32F4xx (probably good enough for STM32F2xx too) // Note, that we won't use the memory-to-memory mode here, as that would simply run not waiting for th…

Hello, I'm working with a STM32F407 controller board.   Right now, I want to trigger a DMA transfer with one of the internal timers (TIM1).   The DMA transfer should read one gpio port and put it into the memory.   The timer is configured in PWM mode…

原文地址:http://www.journaldev.com/2856/java-jvm-memory-model-memory-management-in-java Understanding JVM Memory Model, Java Memory Management are very important if you want to understand the working of Java Garbage Collection. Today we will look into me…

一.理论理解部分. 1.直接存储器存取(DMA)用来提供在外设和存储器之间或者存储器和存储器之间的高速数据传输. 2.无须CPU干预,数据可以通过DMA快速移动,这就节省了CPU的资源来做其他操作. 3.两个DMA控制器有12个通道(DMA1有7个通道,DMA2有5个通道),每个通道专门用来管理来自一个或者多个外设对存储器访问的请求. 4.还有一个冲裁器协调各个DMA请求的优先权.在同一个DMA模块上,多个请求间的优先权可以通过软件编程设置(共有四级:很高.高.中和低),优先权设置相等时由硬件决…

system  memory就是电脑的内存条上的,一般都很大.显卡不能访问 . video memory就是显示卡上的显存,一般是32,64,128M这样,速度最快,显卡可直接访问 .用来描述电脑上一些可写存储区,通常是RAM,用来保存图形卡所需要的用来驱动显示设备的信息.在现代3D图形卡中,video memory也可用来保存3D向量数据,纹理,缓冲区等等,有时候以共享存储结构的形式出现. AGP memory:Accelerated Graphics Port,加速图形接口,AGP是一种接口…

Data transfer from GPIO port to RAM buffer using DMA upon receiving a trigger signal on the timer capture input channel. Our requirement is to configure the DMA so that it transfers data from the GPIO lines (8 bit data lines) to the RAM buffer upon r…

什么是DMA(Direct Memory Access) DMA绕过CPU,在内存和外设之间开辟了一条 "隧道" ,直接控制内存与外设之间的操作,并完全由硬件控制. 这样数据传送不经过cpu,不需要保护.恢复CPU现场等一系列操作,减少开销. 如何运行 向cpu索要系统总线:接受外设发出的DMA请求,并向CPU发出总线请求.CPU响应总线请求,发出总线响应信号,接管总线控制权,进入DMA操作周期. 在系统总线上,进行内存和外设之间的数据传输:确定传送数据的主存单元地址及长度,并能自动修…

DMA(Direct Memory Access) DMA(Direct Memory Access)即直接存储器存取,是一种快速传送数据的机制. 工作原理 DMA是指外部设备不通过CPU而直接与系统内存交换数据的接口技术. 要把外设的数据读入内存或把内存的数据传送到外设,一般都要通过CPU控制完成,如CPU程序查询或中断方式.利用中断进行数据传送,可以大大提高CPU的利用率. 但是采用中断传送有它的缺点,对于一个高速I/O设备,以及批量交换数据的情况,只能采用DMA方式,才能解决效率和速度问题…

The DMA channels can also work without being triggered by a request from a peripheral. This mode is called Memory to Memory mode. If the MEM2MEM bit in the DMA_CCRx register is set, then the channel initiates transfers as soon as it is enabled by sof…

BACKGROUND INFORMATION Various mechanisms exist for managing memory in a virtual machine environment. A virtual machine platform typically executes an underlying layer of software called a virtual machine monitor (VMM) which hosts one to many operati…