How to read & output 32 bits using shift operator?

[Einly]

Dear all,

1) How to write 32 bits through an adc pin using shift operator?

I have successfully output a byte using
output_bit(SDIO,shift_left(&insr,1,0));

Ex:
insr=0x64;

for(i=0;i<8;i++)
{
output_high(SCLK);
output_bit(SDIO,shift_left(&insr,1,0));
delay_us(1);
output_low(SCLK);
delay_us(1);
}

However, I failed to output 32 bits. I check with an oscilloscope & I got low for all the 32 bits. May I know do I make any mistake in my code?
Below is my code:
cmr[3]=0xC0;
cmr[2]=0x00;
cmr[1]=0x02;
cmr[0]=0x27;

delay_us(1);
for(i=0;i<32;i++)
{
output_high(SCLK);
output_bit(SDIO,shift_left(&cmr,4,0));
delay_us(1);
output_low(SCLK);
delay_us(1);
}

2) May I know how should I receive bit through an adc pin? Am I code correct? My code is as shown below...

for(i=0;i<32;i++)
{
output_high(SCLK);
delay_us(1);
output_low(SCLK);
shift_left(cmrrb,4,input(SDIO));
delay_us(1);
}

3) How should I access all the 4 bytes being read?
Is it cmrrb[3], cmrrb[2], cmrrb[1], cmrrb[0]...?


Thanks a lot:-)



Yours truly,
Einly
_________________
Einly

[Haplo]

1) You need to pass the address of the variable into the shift_left() function. Since cmr is an array, its name is already its address, so you'll need to change your code to:
output_bit(SDIO,shift_left(cmr,4,0)); //The & is not needed anymore

2) Please explain more what you are trying to do.

3) You can declare a int32 variable and use it:
int32 cmrrb;
shift_left(&cmrrb,4,input(SDIO)); //The & is needed here


By the way, if you are using the delay statements just to wait for the value of the pins to change, it is better to use delay_cycles(1) rather than delay_us(1), in case your crystal speed is (or will ever be) less than 4MHz.

[Einly]

Dear Haplo,

Hi, Thanks for your reply. Actually I'm using PCM 2.73 which doesn't support int32.

For your answer in question 3. What are the methods that you can suggest?

Wait for your good news.


Regards: Einly,
_________________
Einly

[Haplo]

The first ever PCM I used was PCM 3.112 so I'm afraid I'm not aware of the limitations in PCM 2.73. If it doesn't support int32 then you're probaby stuck with cmrrb[3], cmrrb[2], cmrrb[1], cmrrb[0]. Or if working with int16 variables are easier for you then you can try this code: