i have a problem about pio

Altera_Forum · ‎12-07-2005

i have a problem with pio.

void main

{

unsigned long M=0;

unsigned long N=0;

unsigned long fenzi=0;

unsigned long fenmu=0;

unsigned long em;

M=6997*4*188;

N=7314*204*8*10;

fenzi=M;

fenmu=N;

while(N > 0)

{

em = M % N;

M = N;

N = em;

}

fenzi=fenzi/M;

fenmu=fenmu/M;

}

after i have computer out fenzi and fenmu,i want to trans them to a FPGA module.

the module have three input port (clk,[31:0] fenzi,[31:0] femu).

what should i do ?

may i use 2 pio port?

if so,what is the code?

Altera_Forum · ‎12-08-2005

HI, snow

are u from P.R.C? http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/biggrin.gif

fenzi? fenmu? http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/biggrin.gif

they are called "arenumerator" and "denominator" in English http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/tongue.gif

i know what u mean. and i suggest u can read "Altera Embedded Peripherals Handbook" section 11 "PIO Core with Avalon Interface" and "Nios II Software Developer’s Handbook" section 4 "Developing Programs using the HAL"

good luck

http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/cool.gif

Altera_Forum · ‎12-08-2005

hi oceanx

thank you for your help.

yes, you are right,i am from P.R.C. http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/biggrin.gif

i have read the releated parts of the handbook,and i have try to use it as follows,

# include "excalibur.h"

# include "stdio.h"

# define clk 57600 //73140# define v 7# define outrate 6840

unsigned int Gcd(unsigned int M,unsigned int N)

{

unsigned int Rem;

while(N > 0)

{

Rem = M % N;

M = N;

N = Rem;

}

return M;

}

void main(void)

{

unsigned int wnfenzi,wnfenmu,gcd;

unsigned int rnfenzi,rnfenmu,rnzheng;

unsigned int fenzi,fenmu,faqam,qamfenzi,qamfenmu;

unsigned int inqam;

unsigned int bo,co;

//计算写时钟参数

wnfenzi=outrate*v*188;

wnfenmu=clk*204*8;

gcd=Gcd(wnfenzi,wnfenmu);

wnfenzi=wnfenzi/gcd;

wnfenmu=wnfenmu/gcd;

printf("wnfenzi=%d,wnfenmu=%d\n",wnfenzi,wnfenmu);

na_wnfenzi_pio->np_piodirection=0xffffffff;

na_wnfenmu_pio->np_piodirection=0xffffffff;

na_wnfenzi_pio->np_piodata=wnfenzi;

na_wnfenmu_pio->np_piodata=wnfenmu;

//计算读使能参数

rnfenzi=wnfenmu*47;

rnfenmu=wnfenzi*2;

if(rnfenzi>rnfenmu)

{

rnzheng=rnfenzi/rnfenmu;

rnfenzi=rnfenzi-rnfenmu*rnzheng;

if(rnfenzi==0)

{

rnfenmu=2;

}

rnfenmu=rnfenmu-1;

rnfenzi=rnzheng+rnfenzi;

}

//输出为rnfenmu(factor),rnzheng(conl_1),rnfenzi(conl_2)

printf("rnfenzi=%d,rnzheng=%d,rnfenmu=%d\n",rnfenzi,rnzheng,rnfenmu);

na_rnfenmu_pio->np_piodirection=0xffffffff;

na_rnzheng_pio->np_piodirection=0xffffffff;

na_rnfenzi_pio->np_piodirection=0xffffffff;

na_rnfenmu_pio->np_piodata=rnfenmu;

na_rnzheng_pio->np_piodata=rnzheng;

na_rnfenzi_pio->np_piodata=rnfenzi;

//计算逆速率匹配

faqam=outrate%1000;

inqam=outrate/1000;

if(faqam==0)

{

fenzi=outrate;

fenmu=clk;

}

gcd=Gcd(faqam,1000);

qamfenzi=faqam/gcd;

qamfenmu=1000/gcd;

fenzi=inqam*qamfenmu+qamfenzi;

fenmu=clk*qamfenmu;

printf("fenzi=%d,fenmu=%d\n",fenzi,fenmu);

na_fenzi_pio->np_piodirection=0xffffffff;

na_fenmu_pio->np_piodirection=0xffffffff;

na_fenzi_pio->np_piodata=10;

co=na_fenzi_pio->np_piodata;

na_fenmu_pio->np_piodata=fenmu;

bo=na_fenmu_pio->np_piodata;

}

but when i use modelsim to check the result ,i do not understand the waves.

i mean when the data are written to the pio's data register,will the pio's output be always the data? what should i do if i want to output them at a time ,after all the numbers be computed out?

Altera_Forum · ‎12-08-2005

HI snow

I suggest u can open the "altera_avalon_pio_regs.h" and "system.h" of NIOS2 project in the IDE and read it carefully.

use these followed macro:

IORD_ALTERA_AVALON_PIO_DATA(base)

IOWR_ALTERA_AVALON_PIO_DATA(base, data)

Reading the English Datasheet carefully before u program http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/smile.gif