新建文件 Hardware/SOC/异构多核处理器开发嵌入式应用入门.md
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# [异构多核处理器开发嵌入式应用入门](https://blog.csdn.net/toradexsh/article/details/70278764)
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By Toradex Raul Rosetto Mu?oz
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## 简介
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每天都有新的异构多核处理器/片上系统 SoC 面市。在 SoC 上集成微控制器和外设控制核正变得越来越普遍，看看最新发布的 NXP? ：i.MX 6SoloX、i.MX7 和即将面世的 i.MX 8。在我看来，这有点像曾经 ADC（模数转换器）开始集成微处理器上的外设功能，在应用处理器上集成微控制器，可以解决 Linux 系统中一些实时可控相关的问题。
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新技术的出现总是会引出许多问题，或许你会产生疑问，这是否需要很多工作量。本位旨在快速、明了地介绍一种使用异构多核方式开发应用的方法。这里我们将会涉及搭建开发环境以及创建一个双核通信的 ping pong 应用的基本步骤，最后演示一个用微控制器通过 SPI 读取 ADC 数据并把数据发送至运行 Linux 的处理器的实际应用。
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这是揭示利用异构多核处理构架 SoC 开发嵌入式系统的系列文章。通过实际操作和一些案例演示，你可以快速地开始开发。
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## 硬件
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本文中将使用 Toradex 双核 Colibri iMX7 计算机模块：该模块采用 NXP i.MX7 SoC，一个双核 ARM Cortex-A7 和 一个 ARM Cortex-M4 核心，A7 主频为 1GHz，M4 主频为 200MHz，同时具备 512MB 存储和 512MB 内存。模块如下图所示：
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载板采用 Aster。这是 Toradex 新发布的产品，使新项目开发更加容易。该载板具有标准的 Arduino 接口，使开发人员能够利用市面上丰富的 Arduino 模块，缩减研发时间。除了 Arduino，还有一个兼容 Raspberry Pi 的接口，允许在开发的硬件上使用模块，不仅能够促进新产品的原型开发，也能够帮助从概念验证到可扩展、工业品质、保证生命周期硬件方案如 Toradex 的过渡。
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## 搭建开发环境
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本文中演示的案例是在 Linux 电脑上开发的。所有 Cortex-M 上的代码都基于 Makefile 和 Cmake。你只需要安装少量的软件并正确配置编译工具链，就可以编译示例代码。
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我们建议使用 4.9 2015 Q3 版本 linaro toolchain。从这里下载好压缩包后，解压如下：
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tar xjf ~/Downloads/gcc-arm-none-eabi-4_9-2015q3-20150921-linux.tar.bz2
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因为编译工具生成 32位应用，所以需要安装 32位的 libc 和 libncurse。在 Ubuntu 上，命令如下：
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sudo dpkg --add-architecture i386 sudo apt-get update sudo apt-get install libc6:i386 libncurses5:i386
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现在可以测试编译工具：
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~/gcc-arm-none-eabi-4_9-2015q3/bin/arm-none-eabi-gcc –version
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arm-none-eabi-gcc (GNU Tools for ARM Embedded Processors) 4.9.3 20150529 (release) [ARM/embedded-4_9-branch revision 227977] Copyright (C) 2014 Free Software Foundation, Inc.
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This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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最后，安装 cmake 和 make：
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sudo apt-get install make cmake
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## 下载示例
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我们准备了一些示例，方便下载和测试，包括基本的 双核通信“Hello, World!”。下载源代码：
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$ git clone -b colibri-imx7-m4-freertos-v8 git://git.toradex.com/freertos-toradex.git freertos-colibri-imx7/
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$ cd freertos-colibri-imx7/
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所有我们将会使用的源码都在这个文件夹里面。其中的文件已经能够支持 Colibri iMX7 和 FreeRTOS。在所有这些文件中，我们主要使用包含示例的的文件夹：
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[raul@localhost freertos-colibri-imx7]$ tree -L 2 examples/imx7_colibri_m4/
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examples/imx7_colibri_m4/
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├── board.c
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├── board.h
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├── clock_freq.c
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├── clock_freq.h
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├── demo_apps
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│ ├── blinking_imx_demo
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│ ├── hello_world
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│ ├── hello_world_ddr
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│ ├── hello_world_ocram
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│ ├── low_power_imx7d
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│ ├── rpmsg
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│ └── sema4_demo
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├── driver_examples
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│ ├── adc_imx7d
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│ ├── ecspi
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│ ├── flexcan
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│ ├── gpio_imx
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│ ├── gpt
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│ ├── i2c_imx
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│ ├── uart_imx
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│ └── wdog_imx
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├── gpio_pins.c
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├── gpio_pins.h
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├── pin_mux.c
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└── pin_mux.h
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17 directories, 8 files
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[raul@localhost freertos-colibri-imx7]$
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## 搭建硬件环境
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本文中，我们将不涉及如何调试 Cortex-M 的内容，我们使用 UART 打印固件的输出信息。了解如何搭建产品开发环境是十分重要的。由于 Cortex-M 和 Cortex-A 共享外设接口，你需要知道 UART B 被 Cortex-M 上的固件输出打印信息，UART A 则由 Cortex-A (U-boot and Linux) 使用。
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所以我们将使用 UART A 和 UART B。对于 UART A，在 Aster 上已经有 FTDI 芯片，可以直接连接 USB X4。该接口不仅用于给载板供电，还可以访问 UART-A, 所以当连接到电脑后，/dev/ttyUSBX 设备将会被自动识别。
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对于 UART B, Colibri iMX7 的 TX 和 RX 引脚在 X20 扩展口上。因为没有 FTDI 或者 RS-232 转换器，你需要使用 FTDI 串口线。连接 RX、TX 和 GND 到 X20 的 第8、10、9 引脚。
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最后，图下图所示连接：
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现在都已经正确连接，在 Linux 使用 picocom 打开两个终端，打开串口：
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终端 1：
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[raul@localhost ~]$ picocom -b 115200 /dev/ttyUSB0
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终端 2：
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[raul@localhost ~]$ picocom -b 115200 /dev/ttyUSB1
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## 编译第一个示例
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进入 SPI 示例目录，编译第一个应用：
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[raul@localhost freertos-colibri-imx7]$ cd examples/imx7_colibri_m4/driver_examples/ecspi/ecspi_interrupt/master/
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[raul@localhost master]$ ls armgcc hardware_init.c main.c
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所有的示例都有 main.c 、hardware_init.c 和 armgcc 文件夹。我们先不解释源代码，只是进入目录，导出下载的 toolchain 路径然后编译：
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[raul@localhost armgcc]$ cd ..
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[raul@localhost master]$ cd armgcc/
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[raul@localhost armgcc]$ export ARMGCC_DIR=~/gcc-arm-none-eabi-4_9-2015q3/
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[raul@localhost armgcc]$ ./build_all.sh
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-- TOOLCHAIN_DIR: /home/raul/gcc-arm-none-eabi-4_9-2015q3/
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-- BUILD_TYPE: Debug
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-- TOOLCHAIN_DIR: /home/raul/gcc-arm-none-eabi-4_9-2015q3/
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-- BUILD_TYPE: Debug
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-- Could not determine Eclipse version, assuming at least 3.6 (Helios). Adjust CMAKE_ECLIPSE_VERSION if this is wrong.
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-- The ASM compiler identification is GNU
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-- Found assembler: /home/raul/gcc-arm-none-eabi-4_9-2015q3//bin/arm-none-eabi-gcc
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-- Configuring done
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-- Generating done
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-- Build files have been written to: /home/raul/freertos-colibri-imx7/examples/imx7_colibri_m4/driver_examples/ecspi/ecspi_interrupt/master/armgcc
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Scanning dependencies of target ecspi_interrupt_master_example
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[ 5%] Building C object CMakeFiles/ecspi_interrupt_master_example.dir/home/raul/freertos-colibri-imx7/platform/utilities/src/debug_console_imx.c.obj
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...
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...
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...
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[ 94%] Building C object CMakeFiles/ecspi_interrupt_master_example.dir/home/raul/freertos-colibri-imx7/platform/drivers/src/uart_imx.c.obj
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[100%] Linking C executable debug/ecspi_interrupt_master_example.elf
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[100%] Built target ecspi_interrupt_master_example
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-- TOOLCHAIN_DIR: /home/raul/gcc-arm-none-eabi-4_9-2015q3/
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-- BUILD_TYPE: Release
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-- Eclipse version is set to 3.6 (Helios). Adjust CMAKE_ECLIPSE_VERSION if this is wrong.
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-- Configuring done
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-- Generating done
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CMake Warning:
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Manually-specified variables were not used by the project:
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CMAKE_TOOLCHAIN_FILE
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-- Build files have been written to: /home/raul/freertos-colibri-imx7/examples/imx7_colibri_m4/driver_examples/ecspi/ecspi_interrupt/master/armgcc
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[ 5%] Building ASM object CMakeFiles/ecspi_interrupt_master_example.dir/home/raul/freertos-colibri-imx7/platform/devices/MCIMX7D/startup/gcc/startup_MCIMX7D_M4.S.obj
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...
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...
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...
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[ 94%] Building C object CMakeFiles/ecspi_interrupt_master_example.dir/home/raul/freertos-colibri-imx7/platform/drivers/src/uart_imx.c.obj
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[100%] Linking C executable release/ecspi_interrupt_master_example.elf
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[100%] Built target ecspi_interrupt_master_example
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[raul@localhost armgcc]$
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The binaries are located in the "release" directory.
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[raul@localhost armgcc]$ cd release/
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[raul@localhost release]$ ls
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ecspi_interrupt_master_example.bin ecspi_interrupt_master_example.hex
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ecspi_interrupt_master_example.elf ecspi_interrupt_master_example.map
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[raul@localhost release]$
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在这里， bin 文件是最重要的。我们使用 U-boot 将其加载到 Cortex-M4。
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## 运行固件程序
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为了运行固件程序，U-boot 需要加载这个二进制文件，然后在 Cortex-M 上运行。也可以用另外的方法。我的建议是使用 SD 卡或者网络。我们将会演示如何使用这两种方法。一方面，需要知道的是使用网络，开发将以动态的方式进行，因为不需要在载板上拔插 SD 卡。另一方面，为了使用以太网加载文件，你需要配置 tftp 服务器，我这里配置为 "/srv/tftp/"。参考 Flashing Linux Over Ethernet 了解 tftp 配置。
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SD 卡：
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[raul@localhost release]$ df
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Filesystem 1K-blocks Used Available Use% Mounted on
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/dev/sdb1 7780496 469540 7310956 7% /run/media/raul/DATA
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[raul@localhost release]$ cp ecspi_interrupt_master_example.bin /run/media/raul/DATA
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[raul@localhost release]$ umount /run/media/raul/DATA
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以太网：
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[raul@localhost release]$ cp ecspi_interrupt_master_example.bin /srv/tftp/
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开启载板电源，上电的时候，在 UART-A (U-boot and Linux) 终端上按下任意按键。进入 U-boot，加载可执行文件。
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SD 卡：
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Colibri iMX7 # fatload mmc 0:1 0x7F8000 ecspi_interrupt_master_example.bin
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reading ecspi_interrupt_master_example.bin
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9956 bytes read in 20 ms (485.4 KiB/s)
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以太网：
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Colibri iMX7 # tftp 0x7F8000 ecspi_interrupt_master_example.bin
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Using FEC0 device
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TFTP from server 192.168.0.150; our IP address is 192.168.0.170
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Filename 'ecspi_interrupt_master_example.bin'. Load address: 0x7f8000
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Loading: ################################################## 9.7 KiB
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647.5 KiB/s
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done
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Bytes transferred = 9956 (26e4 hex)
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加载完成后，无论是使用 SD 卡还是以太网，执行下面的命令运作已经加载到 Cortex-M 上的程序。
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Colibri iMX7 # dcache flush
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Colibri iMX7 # bootaux 0x7F8000
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##Starting auxiliary core at 0x007F8000 ...
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Colibri iMX7 #
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接下来，你应该可以看到在 UART B 终端上打印出 Cortex-M 的调试信息。你的屏幕如下图所示。
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在 UART B 终端里按 “s”之前，试着将 SPI MISO 和 MOSI 连接起来。这样就可以看到在回环模式下的通信，不仅是发送数据，还可以接收 SPI 数据。
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-------------------------------------------
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-------------- ECSPI master driver example --------------
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This example application demonstrates usage of SPI driver in master mode.
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It transfers data to/from remote MCU in SPI slave mode.
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Press "s" when spi slave is ready.
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MASTER: Transmited data: 1 :
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Received data: 1
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MASTER: Transmited data: 2 :
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Received data: 2 ... ... ...
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MASTER: Transmited data: 19 :
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Received data: 19
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MASTER: Transmited data: 20 :
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Received data: 20
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-------------------------------------------
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## 示例 - SPI
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在之前的示例中，我们只编译和执行了代码。现在我们将修改源码，实现同 Microchip MCP3008 的 SPI 通信。这个一个10位 ADC，具有8个输入。按下图连接到 Aster 和面包板：
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如果喜欢使用 Eclipse IDE，可以通过 CMake 生成 Eclipse 项目文件。 Cmake 的 -G 参数可以配置 “build system generator”。确保 build_all.sh 指定 “Eclipse CDT4 – Unix Makefiles”。
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在 armgcc 示例目录中：
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[raul@localhost armgcc]$ vi build_all.sh
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#!/bin/sh cmake -DCMAKE_TOOLCHAIN_FILE="../../../../../../../tools/cmake_toolchain_files/armgcc.cmake" -G "Eclipse CDT4 - Unix Makefiles" -DCMAKE_BUILD_TYPE=Debug .
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make -j4
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cmake -DCMAKE_TOOLCHAIN_FILE="../../../../../../../tools/cmake_toolchain_files/armgcc.cmake" -G "Eclipse CDT4 - Unix Makefiles" -DCMAKE_BUILD_TYPE=Release .
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make -j4
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接下来运行 “build_all.sh”脚本：
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[raul@localhost armgcc]$ ./build_all.sh
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[raul@localhost armgcc]$ ls .cproject .project
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.cproject .project
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打开 Eclipse 并导入项目
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File > Import…
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在 “Select root directory”，输入 “armgcc”文件夹目录
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/home/raul/freertos-colibri-imx7/examples/imx7_colibri_m4/driver_examples/ecspi/ecspi_interrupt/master/armgcc
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打开目录中的 main.c”文件
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[TARGET] → [exec]ecspi_interrupt_master_example → Source Files
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标准的示例是十分简单的。我们有必要介绍部分代码，从而在下面的示例中能够清楚地了解需要查看什么地方。
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```cpp
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int main(void)
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{
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uint8_t control_char;
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uint8_t i;
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ecspi_init_config_t ecspiMasterInitConfig = {
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.baudRate = 500000,
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.mode = ecspiMasterMode,
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.burstLength = ECSPI_MASTER_BURSTLENGTH,
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.channelSelect = BOARD_ECSPI_CHANNEL,
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.clockPhase = ecspiClockPhaseSecondEdge,
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.clockPolarity = ecspiClockPolarityActiveHigh,
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.ecspiAutoStart = ECSPI_MASTER_STARTMODE
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};
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/* Hardware initialize, include RDC, CLOCK, IOMUX, ENABLE MODULE */
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hardware_init();
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/* Update clock frequency of this module */
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ecspiMasterInitConfig.clockRate = get_ecspi_clock_freq(BOARD_ECSPI_BASEADDR);
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PRINTF("\n-------------- ECSPI master driver example --------------\n\n\r");
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PRINTF("This example application demonstrates usage of SPI driver in master mode.\n\r");
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PRINTF("It transfers data to/from remote MCU in SPI slave mode.\n\r");
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/* Ecspi module initialize, include configure parameters */
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ECSPI_MasterConfig(&ecspiMasterInitConfig);
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/* Wait slave ready, then press 's' to start communication. */
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while(true)
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{
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PRINTF("Press \"s\" when spi slave is ready.\n\r");
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control_char = GETCHAR();
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if((control_char == 's') || (control_char == 'S'))
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break;
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}
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/* Send 1~20 to slave and receive data from slave */
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for(i = 0; i < 20; i++)
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{
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txData[0]++;
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ECSPI_MasterTransfer((uint8_t*)txData, (uint8_t*)rxData, 1);
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while(ECSPI_MasterGetTransferStatus());
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PRINTF("MASTER: Transmited data: %d \n\r", txData[0]);
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PRINTF(" : Received data: %d \n\n\r", rxData[0]);
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}
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while(1);
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}
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```
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第一个需要注意的配置引脚复用的地方。这里我们将使用标准的 SPI。右击“hardware_init();”函数，选择“Open Declaration”
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```cpp
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void hardware_init(void)
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{
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/* Board specific RDC settings */
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BOARD_RdcInit();
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/* Board specific clock settings */
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BOARD_ClockInit();
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/* initialize debug uart */
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dbg_uart_init();
|
||||
|
||||
/* RDC ECSPI */
|
||||
RDC_SetPdapAccess(RDC, BOARD_ECSPI_RDC_PDAP, 3 << (BOARD_DOMAIN_ID * 2), false, false);
|
||||
/* Select board ecspi clock derived from OSC clock(24M) */
|
||||
CCM_UpdateRoot(CCM, BOARD_ECSPI_CCM_ROOT, ccmRootmuxEcspiOsc24m, 0, 0);
|
||||
/* Enable ecspi clock gate */
|
||||
CCM_EnableRoot(CCM, BOARD_ECSPI_CCM_ROOT);
|
||||
CCM_ControlGate(CCM, BOARD_ECSPI_CCM_CCGR, ccmClockNeededAll);
|
||||
/* Configure ecspi pin IOMUX */
|
||||
configure_ecspi_pins(BOARD_ECSPI_BASEADDR);
|
||||
}
|
||||
```
|
||||
|
||||
主要的硬件初始化和配置都在这个函数中完成。SPI 引脚的配置在最后一个函数“configure_ecspi_pins(BOARD_ECSPI_BASEADDR);”。
|
||||
|
||||
```cpp
|
||||
void configure_ecspi_pins(ECSPI_Type* base)
|
||||
{
|
||||
// ECSPI1 iomux configuration
|
||||
/* daisy chain selection */
|
||||
IOMUXC_ECSPI3_MISO_SELECT_INPUT = 0; //(I2C1_SCL SODIM 90)
|
||||
IOMUXC_ECSPI3_MOSI_SELECT_INPUT = 0; //(I2C1_SCL SODIM 90)
|
||||
|
||||
/* iomux */
|
||||
IOMUXC_SW_MUX_CTL_PAD_I2C2_SCL = IOMUXC_SW_MUX_CTL_PAD_I2C2_SCL_MUX_MODE(3); /* ECSPI SLK */
|
||||
IOMUXC_SW_MUX_CTL_PAD_I2C1_SDA = IOMUXC_SW_MUX_CTL_PAD_I2C1_SDA_MUX_MODE(3); /* ECSPI MOSI */
|
||||
IOMUXC_SW_MUX_CTL_PAD_I2C1_SCL = IOMUXC_SW_MUX_CTL_PAD_I2C1_SCL_MUX_MODE(3); /* ECSPI MISO */
|
||||
IOMUXC_SW_MUX_CTL_PAD_I2C2_SDA = IOMUXC_SW_MUX_CTL_PAD_I2C2_SDA_MUX_MODE(3); /* ECSPI SS0 */
|
||||
|
||||
/* pad control */
|
||||
IOMUXC_SW_PAD_CTL_PAD_I2C2_SCL = IOMUXC_SW_PAD_CTL_PAD_I2C2_SCL_PE_MASK |
|
||||
IOMUXC_SW_PAD_CTL_PAD_I2C2_SCL_PS(0) | /* pull down */
|
||||
IOMUXC_SW_PAD_CTL_PAD_I2C2_SCL_DSE(0) |
|
||||
IOMUXC_SW_PAD_CTL_PAD_I2C2_SCL_HYS_MASK;
|
||||
|
||||
IOMUXC_SW_PAD_CTL_PAD_I2C1_SDA = IOMUXC_SW_PAD_CTL_PAD_I2C1_SDA_DSE(0) |
|
||||
IOMUXC_SW_PAD_CTL_PAD_I2C1_SDA_HYS_MASK;
|
||||
|
||||
IOMUXC_SW_PAD_CTL_PAD_I2C1_SCL = IOMUXC_SW_PAD_CTL_PAD_I2C1_SCL_HYS_MASK;
|
||||
|
||||
IOMUXC_SW_PAD_CTL_PAD_I2C2_SDA = IOMUXC_SW_PAD_CTL_PAD_I2C2_SDA_PE_MASK |
|
||||
IOMUXC_SW_PAD_CTL_PAD_I2C2_SDA_PS(3) | /* pull up */
|
||||
IOMUXC_SW_PAD_CTL_PAD_I2C2_SDA_DSE(0) |
|
||||
IOMUXC_SW_PAD_CTL_PAD_I2C2_SDA_HYS_MASK;
|
||||
}
|
||||
```
|
||||
|
||||
另外一个重要的文件是“board.h”。在同一个函数中，搜索 "configure_ecspi_pins (BOARD_ECSPI_BASEADDR);" 中的 "BOARD_ECSPI_BASEADDR"，你将会发现部分“board.h”内容，这里配置除了 SPI 外的其他内容，例如中断向量表。
|
||||
|
||||
```cpp
|
||||
#define BOARD_ECSPI_RDC_PDAP rdcPdapEcspi3
|
||||
#define BOARD_ECSPI_CCM_ROOT ccmRootEcspi3
|
||||
#define BOARD_ECSPI_CCM_CCGR ccmCcgrGateEcspi3
|
||||
#define BOARD_ECSPI_BASEADDR ECSPI3
|
||||
#define BOARD_ECSPI_CHANNEL ecspiSelectChannel0
|
||||
#define BOARD_ECSPI_IRQ_NUM eCSPI3_IRQn
|
||||
#define BOARD_ECSPI_HANDLER eCSPI3_Handler
|
||||
```
|
||||
|
||||
回到“main.c”我将改变主函数，获取 MCP3008 的数据。具体地讲，我们将读取芯片 channel 0 的数据。
|
||||
|
||||
```cpp
|
||||
/* Wait slave ready, then press 's' to start communication. */
|
||||
while(true)
|
||||
{
|
||||
PRINTF("Press \"s\" when spi slave is ready.\n\r");
|
||||
control_char = GETCHAR();
|
||||
if((control_char == 's') || (control_char == 'S'))
|
||||
break;
|
||||
}
|
||||
```
|
||||
|
||||
删除“break”，增加下面的代码。根据 MCP3008 白皮书，“00000001 10000000 00000000”序列分别表示起始位、通道选择和10位数据的信息。
|
||||
|
||||
```cpp
|
||||
/* Wait slave ready, then press 's' to start communication. */
|
||||
|
||||
while(true)
|
||||
{
|
||||
PRINTF("Press \"s\" when spi slave is ready.\n\r");
|
||||
control_char = GETCHAR();
|
||||
if((control_char == 's') || (control_char == 'S'))
|
||||
{
|
||||
unsigned char datatx[3];
|
||||
unsigned char datarx[3];
|
||||
|
||||
datatx[0] = 0b00000001; // first byte transmitted -> start bit
|
||||
datatx[1] = 0b10000000; // second byte transmitted -> (SGL/DIF = 1, D2=D1=D0=0)
|
||||
datatx[2] = 0b00000000; // third byte transmitted....don't care
|
||||
|
||||
/* SPI Read */
|
||||
ECSPI_MasterTransfer((uint8_t*)&datatx[0], (uint8_t*)&datarx[0], 3);
|
||||
|
||||
while(ECSPI_MasterGetTransferStatus());
|
||||
|
||||
PRINTF("Transmited data: %d \n\r", datatx[0]);
|
||||
PRINTF("Transmited data: %d \n\r", datatx[1]);
|
||||
PRINTF("Transmited data: %d \n\r", datatx[2]);
|
||||
PRINTF("Received data: %d \n\n\r", datarx[0]);
|
||||
PRINTF("Received data: %d \n\n\r", datarx[1]);
|
||||
PRINTF("Received data: %d \n\n\r", datarx[2]);
|
||||
|
||||
unsigned int a2dVal = 0;
|
||||
a2dVal = (datarx[1]<< 8) & 0b1100000000; //merge data[1] & data[2] to get result
|
||||
a2dVal |= (datarx[2] & 0xff);
|
||||
|
||||
PRINTF("data = %d \n\n\r", a2dVal);
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
修改完毕后，“int main (void)” 应该如下：
|
||||
|
||||
```cpp
|
||||
int main(void)
|
||||
{
|
||||
uint8_t control_char;
|
||||
uint8_t i;
|
||||
|
||||
ecspi_init_config_t ecspiMasterInitConfig = {
|
||||
.baudRate = 500000,
|
||||
.mode = ecspiMasterMode,
|
||||
.burstLength = ECSPI_MASTER_BURSTLENGTH,
|
||||
.channelSelect = BOARD_ECSPI_CHANNEL,
|
||||
.clockPhase = ecspiClockPhaseSecondEdge,
|
||||
.clockPolarity = ecspiClockPolarityActiveHigh,
|
||||
.ecspiAutoStart = ECSPI_MASTER_STARTMODE
|
||||
};
|
||||
/* Hardware initialize, include RDC, CLOCK, IOMUX, ENABLE MODULE */
|
||||
hardware_init();
|
||||
|
||||
/* Update clock frequency of this module */
|
||||
ecspiMasterInitConfig.clockRate = get_ecspi_clock_freq(BOARD_ECSPI_BASEADDR);
|
||||
|
||||
PRINTF("\n-------------- ECSPI master driver example --------------\n\n\r");
|
||||
PRINTF("This example application demonstrates usage of SPI driver in master mode.\n\r");
|
||||
PRINTF("It transfers data to/from remote MCU in SPI slave mode.\n\r");
|
||||
|
||||
/* Ecspi module initialize, include configure parameters */
|
||||
ECSPI_MasterConfig(&ecspiMasterInitConfig);
|
||||
|
||||
/* Wait slave ready, then press 's' to start communication. */
|
||||
while(true)
|
||||
{
|
||||
PRINTF("Press \"s\" when spi slave is ready.\n\r");
|
||||
|
||||
control_char = GETCHAR();
|
||||
if((control_char == 's') || (control_char == 'S'))
|
||||
{
|
||||
unsigned char datatx[3];
|
||||
unsigned char datarx[3];
|
||||
|
||||
datatx[0] = 0b00000001; // first byte transmitted -> start bit
|
||||
datatx[1] = 0b10000000; // second byte transmitted -> (SGL/DIF = 1, D2=D1=D0=0)
|
||||
datatx[2] = 0b00000000; // third byte transmitted....don't care
|
||||
|
||||
/* SPI Read */
|
||||
ECSPI_MasterTransfer((uint8_t*)&datatx[0], (uint8_t*)&datarx[0], 3);
|
||||
|
||||
while(ECSPI_MasterGetTransferStatus());
|
||||
|
||||
PRINTF("Transmited data: %d \n\r", datatx[0]);
|
||||
PRINTF("Transmited data: %d \n\r", datatx[1]);
|
||||
PRINTF("Transmited data: %d \n\r", datatx[2]);
|
||||
PRINTF("Received data: %d \n\n\r", datarx[0]);
|
||||
PRINTF("Received data: %d \n\n\r", datarx[1]);
|
||||
PRINTF("Received data: %d \n\n\r", datarx[2]);
|
||||
|
||||
unsigned int a2dVal = 0;
|
||||
|
||||
a2dVal = (datarx[1]<< 8) & 0b1100000000; //merge data[1] & data[2] to get result
|
||||
a2dVal |= (datarx[2] & 0xff);
|
||||
|
||||
PRINTF("data = %d \n\n\r", a2dVal);
|
||||
}
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
重新编译，根据前面的示例通过 SD 卡或者以太网复制，执行二进制程序。
|
||||
|
||||
SD 卡：
|
||||
|
||||
[raul@localhost release]$ df
|
||||
Filesystem 1K-blocks Used Available Use% Mounted on
|
||||
/dev/sdb1 7780496 469540 7310956 7% /run/media/raul/DATA
|
||||
[raul@localhost release]$ cp ecspi_interrupt_master_example.bin /run/media/raul/DATA
|
||||
[raul@localhost release]$ umount /run/media/raul/DATA
|
||||
|
||||
以太网：
|
||||
|
||||
[raul@localhost release]$ cp ecspi_interrupt_master_example.bin /srv/tftp/
|
||||
|
||||
将SD卡插入载板或者配置网络来执行编译好的二进制文件
|
||||
|
||||
SD 卡：
|
||||
|
||||
Colibri iMX7 # fatload mmc 0:1 0x7F8000 ecspi_interrupt_master_example.bin
|
||||
reading ecspi_interrupt_master_example.bin
|
||||
9956 bytes read in 20 ms (485.4 KiB/s)
|
||||
|
||||
以太网：
|
||||
|
||||
Colibri iMX7 # tftp 0x7F8000 ecspi_interrupt_master_example.bin
|
||||
Using FEC0 device
|
||||
TFTP from server 192.168.0.150; our IP address is 192.168.0.170
|
||||
Filename 'ecspi_interrupt_master_example.bin'.
|
||||
Load address: 0x7f8000
|
||||
Loading: ################################################## 9.7 KiB
|
||||
647.5 KiB/s
|
||||
done
|
||||
Bytes transferred = 9956 (26e4 hex)
|
||||
|
||||
一旦固件加载完毕，使用哪种方法就不再重要，执行下面命令运行 Cortex-M 上加载的程序。
|
||||
|
||||
Colibri iMX7 # dcache flush
|
||||
Colibri iMX7 # bootaux 0x7F8000
|
||||
## Starting auxiliary core at 0x007F8000 ...
|
||||
Colibri iMX7 #
|
||||
|
||||
现在使用修改后的代码，在 UART B 终端中按“s”将显示 channel 0 上模拟采集。
|
||||
|
||||
## 同 Linux 之间的冲突
|
||||
|
||||
在使用这些 U-boot 命令之后，你或许想要在启动 Linux 后运行“boot”命令。现在的问题是，我们的示例使用了 UART B 和 the SPI。想要正常启动 Linux，就需要修改 device tree，让 Linux 不去使用这些资源。
|
||||
|
||||
你可以使用下面的命令，暂时关闭 UART B 和 SPI，而无需修改 device tree：
|
||||
|
||||
Colibri iMX7 # setenv fdt_fixup 'fdt addr ${fdt_addr_r} && fdt rm /soc/aips-bus@30800000/spba-bus@30800000/serial@30890000 && fdt rm /soc/aips-bus@30800000/spba-bus@30800000/ecspi@30840000'
|
||||
Colibri iMX7 # saveenv
|
||||
Saving Environment to NAND...
|
||||
Erasing NAND...
|
||||
Erasing at 0x380000 -- 100% complete.
|
||||
Writing to NAND... OK
|
||||
|
||||
更多关于修改 device tree 的内容，可以参考 Toradex 开发者中心网站上的这篇文章。
|
||||
|
||||
## 自动部署
|
||||
|
||||
在我的演示示例中，我通过以太网加载 Cortex-M 固件程序。一个节约时间的方法是自动复制文件到“/dev/tftp/”目录中。在项目的根目录中，打开文件：
|
||||
|
||||
raul@localhost master]$ vi armgcc/CMakeLists.txt
|
||||
|
||||
在最后面添加下面几行内容：
|
||||
|
||||
[raul@localhost master]$ vi armgcc/CMakeLists.txt ADD_CUSTOM_COMMAND(TARGET ${Project_Name}_Main POST_BUILD COMMAND cp ${EXECUTABLE_OUTPUT_PATH}/ecspi_interrupt_master_example.bin /srv/tftp/m4.bin)
|
||||
|
||||
再次运行 “./build_all.sh”脚本，如果使用 Eclipse 编译，你可以在“console”中看到自动执行的命令：
|
||||
|
||||
cp /home/raul/freertos-colibri-imx7/examples/imx7_colibri_m4/driver_examples/ecspi/ecspi_interrupt/master/armgcc/release/ecspi_interrupt_master_example.bin /srv/tftp/m4.bin
|
||||
|
||||
另外一个对我有帮助的优化是，在 U-boot 中创建自动加载固件程序的规则：
|
||||
|
||||
Colibri iMX7 # setenv m4 'tftp 0x7F8000 m4.bin && dcache flush && bootaux 0x7F8000'
|
||||
Colibri iMX7 # setenv bootcmd 'run m4; run ubiboot; setenv fdtfile ${soc}-colibri-${fdt_board}.dtb && run distro_bootcmd;'
|
||||
|
||||
现在，每一次开启模块，就会自动加载固件程序然后运行 Linux。
|
||||
|
||||
## 总结
|
||||
|
||||
在本文中，你可以掌握搭建异构多核处理器构架方案的基本步骤。通过两个演示示例，我们看到了如何在 Colibri iMX7 计算机模块的 HMP SoC Cortex-M4 核上编译和运行代码。我们也了解到 SoC 上的不同内核共享外设接口，所以你需要了解（以及规划）每个内核分配的外设。
|
||||
Loading…
Reference in New Issue