Here are the frames during TEST 05.
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I don't know how helpful this will be by itself. If you need the TSO values in the context of other pins, or other signals somewhere, please let me know.
So I pulled the dump, deciphered the sweep counts given the information you ferreted out, and the results seem impossible. More below.
One thing I see is that TSO6 (0x20) is set whenever the sweep count is non-zero in your dump. I think, however, that this bit logically has to mean either triggered or "at least one sweep
started". Consider the case where the sweep is super slow, like 500ms/DIV, in which case the sweep count will increment ever 5s. However, the TRIG'D light lights up at the start, and stays lit until the sweep is done.
So, I think the TSO register has to have some kind of latching "triggered" or "sweep started" bit, which is almost certainly TSO6 for the A sweep. There almost certainly has to be a "sweep in progress" flag as well. Likely these flags exist for both A and B sweeps? If so, that'd account for 4 out of 8 bits, with the 5th bit being "!single sequence in progress".
Now, looking at the sweep counts and trigger flags, there are several cases where the counts are "impossibly" high:
dt=3.40ms, v=0010110001110011, ct=26 *T*
dt=2.50ms, v=0010001001111111, ct=22 *T*
dt=11.30ms, v=1111111111111111, ct=NANA *T*
dt=2.10ms, v=0001110001110011, ct=16 *T*
dt=2.30ms, v=0001100001110011, ct=18 *T*
dt=2.50ms, v=0010000101110011, ct=21 *T*
dt=1.60ms, v=0001011001110011, ct=14 *T*
dt=2.50ms, v=0010000101110011, ct=21 *T*
dt=2.30ms, v=0001100001110111, ct=18 *T*
dt=2.50ms, v=0010000101110101, ct=21 *T*
dt=1.60ms, v=0001011001110101, ct=14 *T*
dt=3.90ms, v=0011001001110111, ct=32 *T*
dt=2.50ms, v=0010000101110011, ct=21 *T*
dt=1.70ms, v=0001011001110011, ct=14 *T*
dt=2.50ms, v=0010000101110111, ct=21 *T*
This lists the delta time between TSO value reads, and as you see there are as many as 32 sweep counts in a 3.9ms interval, which corresponds to an 8.2kHz sweep frequency, AND the triggered flag is set. The problem is that I can't think of any way for the hardware to route or generate an 8kHz signal to the triggers.
So, what's up with that?