How to merge digits from a step signal into a single number(Simulink)?

Hi, i have the following simulink model, i want to send values to my PIC microcontroller, do some calculations in mikroPascal and send it back to Simulink.

I receive the digits of the number (1 digit= 1 byte) one after another, it looks like a step signal in the scope. Example:

The question is, how can i do this algorithm:

number=number*10+digit;
{i want to concatenate the digits, so number = 123456789}

with Simulink blocks? The biggest problem is that i can't tell simulink to take a sample every 0.01s(that's the period between the digits of the output number) and use the value as the digit parameter in a function which does the same as the equation above. Any ideas? Thanks, and sorry for the big pics

[Azzi Abdelmalek]

It's not clear

Answer 1

[ChristianW]

"User-Defined Functions" is an option.

As another possibility (among many) you can take "Triggered Subsystems", with the trigger >is digit changed< (implemented eg. with memory and logical ~= block).

[ChristianW]