Assume that a division of 2.5 is required, then:
• Counter A would take phase 0 (0 degrees) of the VCO
• Counter B would take phase 4 (180 degree offset)
Output starts High with rising edge on counter A and goes Low with second rising edge counter B. It goes High again with second rising edge of counter A after that and so on.
X-Ref Target - Figure 3-24