Similar to a Timer or Counter data file type, the “Control Data File” has a special structure that is used to maintain the current position being processed in the FIFO stack and to control the process to load new data into the stack and eject data from the stack.
The most important parameters are the Position parameter, which indicates the next available position where a “FIFO Load” instruction can load data into the stack.
Whenever we detect a box at the sizing station, we will trigger the FIFO Load instruction. This instruction loads the value of the source word, into the FIFO stack whenever there is a false to true transition at the input, which sets the EN bit.
The bits that indicate a box has been detected at the sizing station is when either the large or small box counter is triggered, which is the “Count Up” bit on C5:0 or C5:1.
We will add a “One-Shot” instruction after the branch logic so that when either counter has counted up, we will limit the true status of the downstream logic to one scan.
That is what a One-Shot does, and this instruction is often used to ensure an event only affects the logic on one scan.