am335x GPMC与FPGA通信问题

最近在做一个项目，中间有个gpmc'与fpga通信的模块，我的gpmc配置如下，异步、无复用、单读模式

am335x引脚配置如下：

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},

{"gpmc_a1.gpmc_a1",	 OMAP_MUX_MODE0 | AM33XX_PIN_OUTPUT 
| AM33XX_PULL_DISA}, 
{"gpmc_a2.gpmc_a2",	 OMAP_MUX_MODE0 | AM33XX_PIN_OUTPUT 
| AM33XX_PULL_DISA}, 
{"gpmc_a3.gpmc_a3",	 OMAP_MUX_MODE0 | AM33XX_PIN_OUTPUT 
| AM33XX_PULL_DISA}, 
{"gpmc_a4.gpmc_a4",	 OMAP_MUX_MODE0 | AM33XX_PIN_OUTPUT 
| AM33XX_PULL_DISA}, 
{"gpmc_a5.gpmc_a5",	 OMAP_MUX_MODE0 | AM33XX_PIN_OUTPUT 
| AM33XX_PULL_DISA}, 
{"gpmc_a6.gpmc_a6",	 OMAP_MUX_MODE0 | AM33XX_PIN_OUTPUT 
| AM33XX_PULL_DISA}, 
{"gpmc_a7.gpmc_a7",	 OMAP_MUX_MODE0 | AM33XX_PIN_OUTPUT 
| AM33XX_PULL_DISA}, 
{"gpmc_a8.gpmc_a8",	 OMAP_MUX_MODE0 | AM33XX_PIN_OUTPUT 
| AM33XX_PULL_DISA}, 

{"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_csn1.gpmc_csn1",	 OMAP_MUX_MODE0 | AM33XX_PULL_DISA},
{"gpmc_clk.gpmc_clk",	 OMAP_MUX_MODE0 | AM33XX_PULL_DISA},
{NULL, 0},
};

gpmc配置如下：（根据技术手册上的时序图配置的）

#define STNOR_GPMC_CONFIG1  0x00001000

#define STNOR_GPMC_CONFIG2  0x00121201

#define STNOR_GPMC_CONFIG3  0x00060602

#define STNOR_GPMC_CONFIG4  0x100a1a0a

#define STNOR_GPMC_CONFIG5  0x00101213

#define STNOR_GPMC_CONFIG6  0x10000000

在fpga中用逻辑分析仪所得结果如下：

与手册上的时序很接近，但是我用万用表测量cs1引脚，电压很稳定，一直为高（3.25左右），不应该是为低吗，逻辑分析仪怎么测的为正常呢

panpan zuo：

有人没，在线等呀，用fpga仿真模块仿真同样的gpmc写时序时，fpga能正常读数据至fifo；而实际连接时，fpga判断nCS = 0 AND nADV = 0 一直为false，就进进入不了读地址的状态，一直停留在Idle状态

CASE MSTATE ISWHEN IDLE =>DELAY<=0;FIFO_CLEAR<='0';IO_EN<='0';flag_reg<="000";IF(nCS='0' AND nADV='0') THENMSTATE <=LOCK_ADV;ELSEMSTATE <=IDLE;END IF;WHEN LOCK_ADV =>flag_reg<="001";IF(DELAY<1) THENDELAY<=DELAY+1;ADDR_REG <=ADDR;ELSEIF(ADDR_REG=X"26") THENMSTATE <=READ_S1;DELAY<=0;ELSEMSTATE <=IDLE;END IF;END IF;

Steven Liu1：

回复 panpan zuo:

这个问题应该和你对片选的配置有关，请确认两点：

1. 对于你想使用的CS1，是否有做pinmux的初始化，确保pinmux是正确的；

2. 你上述的时序配置，是对于GPMC_Confign_1，这组寄存器进行的吗? （因为所有的片选信号共用了同样的数据线和地址线，如果你错误的配置到了片选0上，你一样能从数据线上、地址线上，检测到这些信号，只是CS1上没有信号。）