Infer the counter sequence and the effect of input a from the trace table. q is a four-bit unsigned value; the counter changes on rising clock edges.
The following stimulus and observed outputs are a newly prepared trace for this exercise:
| rising edge | a | q after edge |
|---|---|---|
| 1 | 0 | 0101 |
| 2 | 0 | 0110 |
| 3 | 0 | 0000 |
| 4 | 0 | 0001 |
| 5 | 1 | 0100 |