I am trying to transfer data between a PC and an FPGA. I am using C++ for the computer program and the FPGA is a Stratix V. On the FPGA, I need to use FIFOs to buffer recieved data and data about to be sent.On the FPGA I am using a PCIE example design from the user CD of the DE5-net kit.
I have managed to write to- and read from- an on chip fifo using PCIE_Write32() and PCIE_Read32(). The user Manual states, however, that these functions are not appropriate for continuous, large data transfers and that PCIE_DmaRead()/PCIE_DmaWrite() should be used instead.
I tried Writing data to the FIFO using PCIE_DmaWrite() and it worked, as I verified by reading the written values with PCIE_Read32(). My problem is that I cannot get PCIE_DmaRead() to work. Whenever I call it it returns a random(but fixed) value, and does not pop anything from the FIFO(doesn't reduce the fill level).
am I doing something wrong or is it only possible to write to, but not read from, FIFOs by using the DMA functions?
here are my code and my design:
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#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#include "PCIE.h"
#define DEMO_PCIE_USER_BAR PCIE_BAR4
#define DEMO_PCIE_IO_LED_ADDR 0x4000010
#define DEMO_PCIE_IO_BUTTON_ADDR 0x4000020
#define DEMO_PCIE_ONCHIP_MEM_ADDR 0x00000000
#define DEMO_PCIE_DDR3A_MEM_ADDR 0x100000000
#define DEMO_PCIE_DDR3B_MEM_ADDR 0x200000000
#define FIFO_WRITE_MEM_ADDR 0x90000
#define FIFO_READ_MEM_ADDR 0x90004
#define ONCHIP_MEM_TEST_SIZE (512*1024) //512KB
#define DDR3A_MEM_TEST_SIZE (2*1024*1024*1024) //2GB
#define DDR3B_MEM_TEST_SIZE (2*1024*1024*1024) //2GB
...
BOOL TEST_DMA_WRITE(PCIE_HANDLE hPCIe) {
BOOL bPass;
int push[10];
int number;
do
{
printf("Please input number of integers to write:");
scanf("%d", &number);
} while (number < 0 || number > 10);
for (int i = 0; i < number; i++)
{
printf("Please input fifo data:");
scanf("%d", push + i);
}
bPass = PCIE_DmaWrite(hPCIe, FIFO_WRITE_MEM_ADDR, push, number*sizeof(int));
if (bPass)
printf("write success, data=%d\r\n", push[0]);
else
printf("write failed\r\n");
return bPass;
}
BOOL TEST_DMA_READ(PCIE_HANDLE hPCIe) { //doesn't work !!!
BOOL bPass = TRUE;
int Status[10];
int number;
do
{
printf("Please input number of integers to read:");
scanf("%d", &number);
} while (number < 0 || number > 10);
bPass = PCIE_DmaRead(hPCIe, FIFO_READ_MEM_ADDR, Status, number * sizeof(int));
if (bPass)
{
for (int i = 0; i < number; i++)
{
printf("data read:=%d\r\n", Status[i]);
}
}
else
{
printf("Failed to read data\r\n");
}
return bPass;
}
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