BeagleBone GPMC接口读写FPGA双口RAM 高速数据采集 DDS波形发生器

只看该作者 · 2017-10-12 10:51

1、TI GPMC 简要说明

通用存储器控制，即用来访问外部存储器的。主要参考下《AM335x ARM ® Cortex™-A8 Microprocessors(MPUs) TechnicalReferenceManual 》该文档的7.1 GPMC。

支持的外部存储器说明：

存储器类型：NORFlashlike,asynchronous and synchronous devices或者NAND Flashlike devices,stream mode

数据总线宽度：8-bits或者16-bits

地址数据总线复用情况：non-multiplexed/AD/AAD（AAD没见过）

同步和异步区别在于：同步需要时钟信号，异步不需要时钟信号，具体自己去体会哈。

GPMC读支持single access及multiple access(burst if synchonous,pageifasynchronous)

，写支持Single access及Multipleaccess(burstifsynchronous,considered as singleifasynchronous) ，

目前Multipleaccess还没弄明白。

由于需要用GPMC读写FPGA 双口RAM，所以采用synchonous single access NOR Flashlike 16bit模式。

2、试验过程

（1）BeagleBone通过GPMC接口读写FPGA做的双口单时钟（读写时钟共用GPMC时钟）RAM。

（2）高速数据采集：FPGA控制高速AD ，FPGA做的双口双时钟（读写时钟分开）RAM作为AD数据缓存，GPMC时钟用作RAM读时钟，FPGA PLL输出时钟作高速AD采样时钟及写RAM时钟；

（3）DDS波形发生器，目前DDS还没有开始做。

简单完成BeagleBone通过GPMC写双口双时钟（读写时钟分开）RAM，即将高速DA需要的数据预存在RAM里，FPGA PLL输出时钟作高速DA时钟及读RAM时钟，FPGA读RAM预存的数据送到高速DA实现固定频率波形产生。

3、GPMC实现

（1）Linux板文件里初始化GPMC相关管脚

板文件路径：/root/bone-linux/arch/arm/mach-omap2

/root/bone-linux/ 改成自己的ARM Linux源码目录

相关代码：

/* Pin mux for fpga module */
static struct pinmux_config fpga_pin_mux[] = {
{"gpmc_ad0.gpmc_ad0", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ad1.gpmc_ad1", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ad2.gpmc_ad2", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ad3.gpmc_ad3", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ad4.gpmc_ad4", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ad5.gpmc_ad5", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ad6.gpmc_ad6", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ad7.gpmc_ad7", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ad8.gpmc_ad8", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ad9.gpmc_ad9", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ad10.gpmc_ad10", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ad11.gpmc_ad11", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ad12.gpmc_ad12", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ad13.gpmc_ad13", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ad14.gpmc_ad14", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"gpmc_ad15.gpmc_ad15", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
{"lcd_data0.gpmc_a0", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
{"lcd_data1.gpmc_a1", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
{"lcd_data2.gpmc_a2", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
{"lcd_data3.gpmc_a3", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
{"lcd_data4.gpmc_a4", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
{"lcd_data5.gpmc_a5", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
{"lcd_data6.gpmc_a6", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
{"lcd_data7.gpmc_a7", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
{"lcd_vsync.gpmc_a8", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
{"lcd_hsync.gpmc_a9", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
{"lcd_pclk.gpmc_a10", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
{"lcd_ac_bias_en.gpmc_a11", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
{"lcd_data8.gpmc_a12", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
{"lcd_data9.gpmc_a13", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
{"lcd_data10.gpmc_a14", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
{"lcd_data11.gpmc_a15", OMAP_MUX_MODE1 | AM33XX_PIN_OUTPUT | AM33XX_PULL_DISA},
// {"gpmc_wait0.gpmc_wait0", OMAP_MUX_MODE0 | AM33XX_PIN_INPUT_PULLUP},
// {"gpmc_wpn.gpmc_wpn", OMAP_MUX_MODE7 | AM33XX_PIN_INPUT_PULLUP},
// {"gpmc_csn0.gpmc_csn0", OMAP_MUX_MODE0 | AM33XX_PULL_DISA},
{"gpmc_csn0.gpio1_29", OMAP_MUX_MODE7 | AM33XX_PIN_INPUT},
{"gpmc_csn1.gpmc_csn1", OMAP_MUX_MODE0 | AM33XX_PULL_DISA},
//{"gpmc_csn1.gpio1_30", OMAP_MUX_MODE7 | AM33XX_PIN_INPUT},
// {"gpmc_csn2.gpmc_csn2", OMAP_MUX_MODE0 | AM33XX_PULL_DISA},
{"gpmc_csn2.gpio1_31", OMAP_MUX_MODE7 | AM33XX_PIN_INPUT},
// {"gpmc_advn_ale.gpmc_advn_ale", OMAP_MUX_MODE0 | AM33XX_PULL_DISA},
{"gpmc_oen_ren.gpmc_oen_ren", OMAP_MUX_MODE0 | AM33XX_PULL_DISA},
{"gpmc_wen.gpmc_wen", OMAP_MUX_MODE0 | AM33XX_PULL_DISA},
// {"gpmc_ben0_cle.gpmc_ben0_cle", OMAP_MUX_MODE0 | AM33XX_PULL_DISA},
{"gpmc_clk.gpmc_clk", OMAP_MUX_MODE0 | AM33XX_PULL_DISA | <font color="#ff0000">AM33XX_INPUT_EN</font>},
{NULL, 0},
};

[color=rgb(51, 102, 153) !important]复制代码

特别注意GPMC_CLK的AM33XX_INPUT_EN属性的配置，未知管脚需要到文件mux33xx.c下修改相关内容。csn1作片选，csn0、2作GPIO用。

（2）GPMC驱动设计

主要参考内核源代码里的gpmc.c以及gpmc.h文件，内核里是platform平台驱动，我改成了最基础的字符设备驱动，水平有限。

源码文件见附件：附件1：GPMC驱动源码

（3）读写应用程序编写

源码文件见附件：附件2：读写应用程序源码

4、FPGA端程序设计

（1）FPGA与BeagleBone的连接：

（2）FPGA管脚配置TCL文件相关部分：

set_location_assignment PIN_118 -to GPMC_A[1]
set_location_assignment PIN_113 -to GPMC_A[2]
set_location_assignment PIN_114 -to GPMC_A[3]
set_location_assignment PIN_104 -to GPMC_A[4]
set_location_assignment PIN_112 -to GPMC_A[5]
set_location_assignment PIN_101 -to GPMC_A[6]
set_location_assignment PIN_103 -to GPMC_A[7]
set_location_assignment PIN_87 -to GPMC_A[8]
set_location_assignment PIN_81 -to GPMC_AD[0]
set_location_assignment PIN_80 -to GPMC_AD[1]
set_location_assignment PIN_57 -to GPMC_AD[2]
set_location_assignment PIN_58 -to GPMC_AD[3]
set_location_assignment PIN_79 -to GPMC_AD[4]
set_location_assignment PIN_76 -to GPMC_AD[5]
set_location_assignment PIN_53 -to GPMC_AD[6]
set_location_assignment PIN_55 -to GPMC_AD[7]
set_location_assignment PIN_73 -to GPMC_AD[8]
set_location_assignment PIN_65 -to GPMC_AD[9]
set_location_assignment PIN_67 -to GPMC_AD[10]
set_location_assignment PIN_71 -to GPMC_AD[11]
set_location_assignment PIN_64 -to GPMC_AD[12]
set_location_assignment PIN_63 -to GPMC_AD[13]
set_location_assignment PIN_70 -to GPMC_AD[14]
set_location_assignment PIN_69 -to GPMC_AD[15]
set_location_assignment PIN_72 -to GPMC_CLK
set_location_assignment PIN_75 -to GPMC_CSN
set_location_assignment PIN_59 -to GPMC_OEN_REN
set_location_assignment PIN_60 -to GPMC_WEN

[color=rgb(51, 102, 153) !important]复制代码

5、BeagleBone通过GPMC接口读写FPGA做的双口单时钟（读写时钟共用GPMC时钟）RAM SignalTapII抓图：

BeagleBone GPMC接口读写FPGA双口RAM 高速数据采集 DDS波形发生器

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