Convert an array for serial communication

I am trying to send some data through SCI2 serial transmit, but I am unable to do because I have to send only one byte per sampling time. How do I convert an array of 80 bytes, so that I am storing the whole array in a buffer, and releasing one byte every sampling time?

I have tried using Unbuffer block but it wouldnt work. Any help will be appreciated. Thanks

[Walter Roberson]

You mention "Unbuffer block": is this a Simulink question?