NICard 6031E Acquisition too slow when synchronisation with ATMEGA128

Question

Hello:
I have an NI Card 6031E acquiring in HARDWARE SAMPLE CLOCK timing mode which means I supply a clock from an ATMEGA128 and the card acquires a value after each CLOCK high from another ASIC (Multiplexer chip).
The clock comes from a microcontroller ATMEGA128.
PROBLEM: I send an ' r ' character to the ATMEGA128 and subsequently I call the SAMPLE CLOCK timing read function in my user interface Visual C++ 6.0 on the PC. I am trying to synchronise PC with ATMEGA and NICARD data read, BUT I CANT DO IT.
The thing is when the ' r ' char is received at the ATMEGA128 this one does what it has to do just ONCE and may be does it too fast for the NICARD to read the values supplied by the CLOCK from the ATMEGA128.
The ATMEGA128 supplies a few digital binary signals (0 or 1) to the ASIC and the ASIC having received that particular sequence or digital waveform it sends the data (128 values one after each CLOCK high) to the NICARD.
Therefore, each CLOCK high delivers a value to the NICARD from the ASIC. The problem is that it seems I loose the data on the NICARD because the sequence is done very fast at the ATMEGA128 and the NICARD takes 480us I think to perform an instruction. I tried placing the READ function before sending the r char but it blocks.
I need SYNCHRONISATION between the NICARD acquiring values and the ATMEGA128 sending the clock and the ASIC sending data. Can I use other CHARS. I am lost! HELP! -)
Thanks,
Javi

Answer 1

The ATMEGA128 code structure and CLOCK signal is as such:
1 - FOR loop, therefore repeats itself always until you come out of the program execution.
INSIDE FOR LOOP:
2 - wait 1 microsecond, CLOCK HIGH, wait 1 micro second and CLOCK LOW
3 - wait 26.4 microseconds, another FOR loop and inside it, (128 times CLOCK HIGH, wait 1 micro second and CLOCK LOW, and wait 26.4 micro seconds).
4 - Once finished program goes back to 1
So therefore the frequency of the CLOCK is of 37878.78 Hz or 37878.78 HIGH CLOCKS or samples per second which comes from 1/26.4microseconds.
However, the initial first CLOCK on the FOR loop starting in section 1 is HIGH after 1 microsecond as described in section 2.
The sampling frequency is set at 50000 samples per second on the NICARD, so therefore it is a sufficient setting for a 37878.78 Hz CLOCK.
I acquire the data via an NICARD and my code sends an "r" character from the VISUAL C++ user interface to the ATMEGA128 and when the ATMEGA128 receives the "r" char it SENDS the CLOCK (and relevant waveform) to an ASIC. Then when the NICARD receives the CLOCK it acquires 1 sample on every CLOCK HIGH.
I noticed a few days ago that when I start the CLOCK from the ATMEGA (same as sending an "r" char to the ATMEGA) on another Visual C++ application without the NICARD acquisition software functions and at the same time I start the Visual c++ application with the NICARD functions, I get almost the correct data.
It seems that separating both Visual C++ applications PARTIALLY works but it does not make much sense.
The difference between both is just having the NICARD functions present or not present, it seems, although it could be something else too.
As you can see the synchronisation between the NICARD (HARDWARE TIMING CLOCK) data acquisition and the ATMEGA128 or ASIC sending data is performed via the sending of the "r" char to the ATMEGA128.
Thanks.
Javi.