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本帖最后由 reloaded 于 2016-5-22 22:55 编辑
参考链接
http://www.pieter-jan.com/node/15
https://www.raspberrypi.org/foru ... 142439&p=942349
首先，不要用wiring pi或者传统的python脚本，bash脚本做高速的gpio操作，或高速外设访问，因为这两个一个是电子积木毒害较深，一个是高级语言速度慢
所以还是要用传统的low level c ，通过mmap的方式读写io
问题： raspberry pi2,3 的地址变了，如果你不修改库文件的h文件，并且重新建立库，你肯定是没法用的。
办法： #define BCM2708_PERI_BASE 0x3F000000 //注释到和2代无关的一代部分的定义
重新cmake 库，cmake 例子 运行 ok
ps： 关于高速操作io或外设如spi adc 芯片，有个文章讲了下mmap才是真正的底层操作
http://www.hertaville.com/interf ... rry-pi-using-c.html
亦可参考下一链接http://forum.lemaker.org/thread-22815-1-1.html
可见spi部分的代码通过此方法可以构建并正常工作
This solution is meant for applications where real-time constraints such as sampling speed requirements are very modest or even non-existent.
If you have strict sampling requirements, consider one of the following approaches:
Access the SPI registers directly by mmaping into /dev/mem or via the bcm2835 library.
Bitbang SPI via GPIO or use a Parallel ADC connected to the RPI's GPIOs. The RPI GPIOs can be controlled by many different methods, one of which can achieve 20MHz + toggling speed (also mmaping into /dev/mem or via the bcm2835 library but for GPIOs)
Write your own custom/optimized ADC device driver. Have a look at the 24th (June 2014) edition of the MagPi Magazine. The first article explains how to write a Linux driver for a 6-bit 10MSPS ADC and use it in conjunction with GNUplot to plot the waveforms.
Use a microcontroller with a decent built-in ADC and generous amounts of memory for buffering....and maybe a DMA unit e.g. STM32F0/1/2/3/4, TIVA C , PIC32MX, PIC32MZ, e.t.c. The micro can then transmit ADC data to the RPI over UART, SPI or I2C.
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阿莫论坛20周年了！感谢大家的支持与爱护！！
曾经有一段真挚的爱情摆在我的面前，我没有珍惜，现在想起来，还好我没有珍惜……
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发表于 2016-5-22 22:44:30
楼主