iCore4T上，RAM通过SPI4总线与FPGA通信，今天，我将给大家分享RTT添加SPI总线和FPGA驱动，最后实现FPGA的读写测试。

/*
 * Copyright (c) 2006-2018, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2020-02-17     zh.          first version
 */
 
#include <board.h>
#include <drv_spi.h>
#include <rtdevice.h>
#include <rthw.h>
#include <finsh.h>

#include <ctype.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>

#ifdef BSP_USING_SPI_FPGA

/* fpga command */
#define FPGA_READ_ID_CMD			0x01
#define FPGA_WRITE_LEN_CMD			0x02
#define FPGA_WRITE_STATE_CMD		0x03
#define FPGA_WRITE_CMD				0x04
#define FPGA_READ_LEN_CMD			0x05
#define FPGA_READ_STATE_CMD			0x06
#define FPGA_READ_CMD				0x07

/* spi bus device name*/
#define FPGA_SPI_DEVICE_NAME				"spi4"

/* spi device name*/
#define FPGA_DEVICE_NAME					"FPGA"

struct rt_spi_device *spi4_device;


static int spi_write_read_test(void)
{
	rt_uint32_t i;
	rt_uint32_t temp;
	rt_size_t t_size = 0;
	rt_uint8_t send_buffer[1028];
	rt_uint8_t recv_buffer[1028];
	rt_uint8_t error = 0;
	float speed;
	
	/* write command */
	send_buffer[0] = FPGA_WRITE_CMD;
	send_buffer[1] = 0x00;
	send_buffer[2] = 0x00;
	/* pseudo command */
	send_buffer[1027] = 0x00;
	
	for(i = 0;i < 1024;i ++)
	{
		send_buffer[i + 3] = i % 256;
	}
	
//	t_size = rt_spi_transfer(spi4_device,send_buffer,recv_buffer,sizeof(send_buffer));
	temp = HAL_GetTick();
	for(i = 0;i < 10240;i ++)
	{
		t_size = rt_spi_transfer(spi4_device,send_buffer,recv_buffer,sizeof(send_buffer));
	}
	temp = HAL_GetTick() - temp;		
	
	if(t_size != sizeof(send_buffer))
	{
		rt_kprintf("fpga write fail!\n");
		return RT_ERROR;
	}
	
	rt_thread_mdelay(100);
	
	//read_command
	send_buffer[0] = FPGA_READ_CMD;
	send_buffer[1] = 0x00;
	send_buffer[2] = 0x00;
	/* pseudo command */		
	send_buffer[3] = 0x00;

	
	memset(recv_buffer,0,sizeof(recv_buffer));
	
	t_size = rt_spi_transfer(spi4_device,send_buffer,recv_buffer,sizeof(send_buffer));

	if(t_size != sizeof(send_buffer))
	{
		rt_kprintf("fpga read fail!\n");
		return RT_ERROR;
	}
	else
	{
		for(i = 0;i < 1024;i ++)
		{
			if(recv_buffer[i+4] != i%256)
			{
				error ++;
				break;
			}
		}	
	}
	
	if(error)
	{
		rt_kprintf("fpga test fail!\n");
	}
	else
	{
		speed = 10000./temp;
		temp = speed * 100;
		rt_kprintf("fpga test ok!\n");
//		rt_kprintf("speed : %d.%02dMBytes/s\n",temp/100,temp%100);
	}
	
	return RT_EOK;
}

MSH_CMD_EXPORT(spi_write_read_test,fpga);

static int rt_hw_spi_fpga_probe(void)
{
	struct rt_spi_configuration cfg;
	rt_size_t t_size = 0;
	rt_uint8_t send_buffer[5];
	rt_uint8_t recv_buffer[5];
	rt_uint8_t fpga_id;
	
	/* find spi4 device*/
	spi4_device = (struct rt_spi_device *)rt_device_find(FPGA_DEVICE_NAME);
	if(spi4_device == RT_NULL)
	{
		rt_kprintf("ERROR: SPI device %s not found!\n", FPGA_DEVICE_NAME);
		return RT_ERROR;	
	}
	
	/* config spi4 bus */
	cfg.data_width = 8;
	cfg.max_hz = 130*1000*1000;
	cfg.mode = RT_SPI_MASTER | RT_SPI_MODE_3 | RT_SPI_MSB;
	rt_spi_configure(spi4_device, &cfg);
	
	/* get fpga ID*/
	send_buffer[0] = 0x01;
	
	t_size = rt_spi_transfer(spi4_device,send_buffer,recv_buffer,sizeof(send_buffer));
	if(t_size != sizeof(send_buffer))
	{
		rt_kprintf("[FPGA] probe fail!");
		return RT_ERROR;
	}
	else
	{
		rt_kprintf("[FPGA] probe ok! ID is 0x%02X\n",recv_buffer[4]);
		
		fpga_id = recv_buffer[4];
		
		return fpga_id;
	}
}

static int rt_hw_spi4_fpga_init(void)
{
	__HAL_RCC_GPIOE_CLK_ENABLE();
	
	/* attach fpga to spi bus */
	rt_hw_spi_device_attach(FPGA_SPI_DEVICE_NAME, FPGA_DEVICE_NAME, GPIOE, GPIO_PIN_4);
	
	/* probe fpga */
	rt_hw_spi_fpga_probe();
	
	return RT_EOK;
}

INIT_COMPONENT_EXPORT(rt_hw_spi4_fpga_init);

static int fpga(int argc, char **argv)
{
	int result = RT_EOK;
	
    if (argc > 1)
    {
		if(!strcmp(argv[0],"fpga"))
		{
			if (!strcmp(argv[1], "probe"))
			{
				if (argc == 2)
				{
					rt_hw_spi_fpga_probe();
				}
				else
				{
					rt_kprintf("Bad command. Please enter 'fpga' for help\n");
				}
			}
			else if (!strcmp(argv[1], "test"))
			{
				if (argc == 2)
				{
					spi_write_read_test();
				}
				else
				{
					rt_kprintf("Bad command. Please enter 'fpga' for help\n");
				}
			}
			else
			{
				rt_kprintf("Bad command. Please enter 'fpga' for help\n");
			}		
		}
		else
		{
			rt_kprintf("Bad command. Please enter 'eeprom' for help\n");
		}
    }
    else
    {
        rt_kprintf("Usage: \n");
        rt_kprintf("fpga probe                      - read fpga id value\n");
		rt_kprintf("fpga test                       - write & read test fpga\n");
        result = -RT_ERROR;
    }
	
    return result;
}
MSH_CMD_EXPORT(fpga, fpga function);
#endif /* BSP_USING_SPI_FPGA */

至此说明我们的RAM-FPGA通信成功。

源代码可以稳步这里下载：

链接：https://pan.baidu.com/s/1fcLU4WaRDlgr0mNYwZj1Yg  提取码：zstq