NIOS II C language about SDRAM IOWR & IORD function and fopen & fclose

[teddy80]

Hi, I'm new about Quartus II & NIOS II.
I made hardware part using sopc builder (nios II cpu, sdram, on-chip mem,
jtag, sysid, and so on)
and composed c source code for software part.

I want to get right output data from 'printf' function
and test1.txt file from 'fopen, fprintf, fclose' function
,but i didn't get any right result.
How can I solve this problems?

================================================== =====
#include <stdio.h>
#include <unistd.h>
#include "system.h"

#define DEBOUNCE 10000

int main()
{
int input_data = 0x0001;
int output_data;
FILE *fp;

IOWR(SDRAM_0_BASE, 0, input_data);
output_data = IORD(SDRAM_0_BASE, input_data);
printf("output data = %d\n", output_data);

fp = fopen("C:\test1.txt", "w");
fprintf(fp, "%d", output_data);
fclose(fp);
return 0;
}
================================================== =====

Thanks in advance.

[akira]

> fp = fopen("C:\test1.txt", "w");
if you know where is "c:\" on your board?

when you just create CPU(NiosII)
you don't have file-system
you need to create file-system as well.( Linux, uC-OSII or by yourself).

[Cris72]

Hi Teddy,
Apart from the fopen issue, I'm concerned about the two R/W instructions:

IOWR(SDRAM_0_BASE, 0, input_data);
 output_data = IORD(SDRAM_0_BASE, input_data);

Problem 1:
You are writing to address 0 and reading from address 1 (content of input_data) which has not been initialized.
Maybe, you meant this:

output_data = IORD(SDRAM_0_BASE, 0);

Problem 2:
Are you sure this part of sdram is not already used for anything else?
Otherwise your IOWR would corrupt code or other data.

Cris

[pillemann]

Hi teddy,

p = fopen("C:\test1.txt", "w");
fprintf(fp, "%d", output_data);
fclose(fp);

Akira is right. You need a filesystem for that.


But as Cris mentioned, I am also concerned about the IOWR/IORD-part.
If I got you right, you want to write input_data to some SDRAM-address and read it back for printing it.

First: I would let the compiler allocate memory for you, unless you know what is at the specified address. You can use malloc or something like that or you just declare a variable.

For example (assumed that data region is located at SDRAM):

#include <stdio.h>
#include <unistd.h>
#include "system.h"

int input_data = 1;
int output_data = 0;
int output_data_read = 0;

int main()
{
    IOWR(&output_data,0,input_data); // write input_data to output_data with IOWR
    output_data_read = IORD(&output_data,0); // read it back from output_data to output_data_read
    printf("output data = %d\n", output_data_read); // printing on STDOUT
   return 0;
}

Second: I would usually use IOWR/IORD only in cases where it can be neccessary. Like bypassing the data cache. Otherwise, better use standard C-coding for accessing memory.

Regards,
Philipp

[teddy80]

Hi Teddy,
Apart from the fopen issue, I'm concerned about the two R/W instructions:

IOWR(SDRAM_0_BASE, 0, input_data);
 output_data = IORD(SDRAM_0_BASE, input_data);

Problem 1:
You are writing to address 0 and reading from address 1 (content of input_data) which has not been initialized.
Maybe, you meant this:

output_data = IORD(SDRAM_0_BASE, 0);

Problem 2:
Are you sure this part of sdram is not already used for anything else?
Otherwise your IOWR would corrupt code or other data.

Cris

Thanks for your answer.
I used 16bit input_data in c code and
16bit SDRAM using SOPC Builder,
but I got only 8bit output_data.
Where is the problem?

<result>
output data1 = 11111111
output data2 = 10101010

=================================================
#include <stdio.h>
#include <unistd.h>
#include "system.h"

int main()
{
long input_data1 = 0x0000000011111111;
long input_data2 = 0x1010101010101010;
long output_data1;
long output_data2;

IOWR(SDRAM_0_BASE, 0, input_data1);
output_data1 = IORD(SDRAM_0_BASE, 0);
printf("output data1 = %x\n", output_data1);

IOWR(SDRAM_0_BASE + 1, 0, input_data2);
output_data2 = IORD(SDRAM_0_BASE + 1, 0);
printf("output data2 = %x\n", output_data2);

return 0;
}
=================================================

[teddy80]

> fp = fopen("C:\test1.txt", "w");
if you know where is "c:\" on your board?

when you just create CPU(NiosII)
you don't have file-system
you need to create file-system as well.( Linux, uC-OSII or by yourself).

Hi again!
Do you know how can I get from SDRAM data to my hard driver?
My goal is to have binary data of txt file form...

Thanks for your continuous concern.

[Cris72]

Teddy,
0x prefix stands for hex number. One hex digit = 4bit !!!
You must use 0b00101... to specify a binary number.
Moreover, your 'long' data variables are actually 64bit long !
You are getting the correct 32bit prints with %x format.
If you want complete 64bit print you should use %lx or %llx
If you want ram native 16bit data access, you should define variables as 'short'.

Cris

[pillemann]

int main()
{
long input_data1 = 0x0000000011111111;
long input_data2 = 0x1010101010101010;
long output_data1;
long output_data2;

IOWR(SDRAM_0_BASE, 0, input_data1);
output_data1 = IORD(SDRAM_0_BASE, 0);
printf("output data1 = %x\n", output_data1);

IOWR(SDRAM_0_BASE + 1, 0, input_data2);
output_data2 = IORD(SDRAM_0_BASE + 1, 0);
printf("output data2 = %x\n", output_data2);

return 0;
}

I think it is not possible to perform 64 bit IOWR.

If you want to write 64 bit data you have to split it up into 2*IOWR.
Use IOWR twice.

Or am I wrong here? NIOS is 32bit

[akira]

oh you are teddy80
hi again.

if you have UART(RS-232C)
you can program on NiosII to send data from SDRAM.
and your computer can get RS232C data some how like hyper terminal.
RS232C is slow...
there is several way. LAN / SD-Card / USB ...
but many things are difficult after all.
you need to learn more.

UART is easy to use.
I recommend biginer to use UART to read data from embedded system.

see you and good luck