00 to FF reading from UNO and writing into memory of DUE.

hi, i am writing 0 to 255 on UNO's port D this is updating at 1 microsecond each count, the same i m reading from DUE's pin no 22 to 29, i want to Write this data into DUE's memory, so in DUE i want 255 bytes of data in first 00 to FF memory location, i also want to retrive that data so that i will print it to Serial in Excel sheet. kindly help me. Thanks.

How are you sending to PORTD and how do know its at 1uS rate? Have you timed it?

i am writing 0 to 255 on PORT D of UNO's i put delay of 1Microseconds before updating next count.

PORT D of UNO's is connecting to DUE's Pin no 22 to 29 by Physical connections using jumper wires.

"Caveats and Known Issues
This function works very accurately in the range 3 microseconds and up. We cannot assure that delayMicroseconds will perform precisely for smaller delay-times."

So I have my doubts that you are updating like you think you are.

1uS is 16 clocks at 16 MHz, so you'll need pretty good code to output at that speed.



with this at the top of the sketch:
#define nop asm volatile ("nop")
You'll have to experiment to see how many clock cycles the while() uses.

my code is

void setup()
DDRD = B11111111; // set PORTD (digital 7~0) to outputs

void loop()
int i=0;
for (i=0;i<=255;i++)
PORTD = i;

This is 3 milliseconds (30000 microseconds)
not 1 microsecond.

The for( ) takes longer than 1uS itself not counting any code in the { } part.

yes, it was code for 3 millisecods. i used 1 microsecods using delayMicrosecods(1).

anyway let me tel u my application , i am going to build like logic analyzer with DUE, in that i am gonna build it for 32 channels. i want to use 32 digital pins of DUE, and store it and process it. i want to acquire all 32 bits/pins at more than 1 MSPS. this is my application.

now i am making some calibrator using UNO as uno have 8 bit port that we can access directly like 8051's port. i am generating 0 to 255 data on UNO's PORT D and i want to read it with DUE. if this works then next i will READ 32 PINS OF DUE.