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

[Altera_Forum]

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.

[Altera_Forum]

> 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).

[Altera_Forum]

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

[Altera_Forum]

Hi teddy, 

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

[Yogesh]

Hi,
How to use standard C coding to access memory as per your answer?
I am having an array of data say 1,2,3...10. I want to write this data to FPGA memory( say address 1,2,3...10) using C code .
How to do this ? Can you please provide a sample code to do the same ?

Thankyou
Regards,
Yogesh

[Altera_Forum]

--- Quote Start ---  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  --- Quote End ---     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; } =================================================

[Altera_Forum]

--- Quote Start ---  > 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).  --- Quote End ---     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.

[Altera_Forum]

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

[Altera_Forum]

--- Quote Start ---  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; }  --- Quote End ---  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

[Altera_Forum]

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