Another serial decoder bug to report, this time on the I2C decoder.
I'm using an STM32F469 to read data from a TH02 temperature sensor (HopeRF). I have the analog channels 1 and 2 hooked up to SDA and SCL, respectively. First, I noticed that, unlike for the serial decoder, I can't make an acquisition and then zoom in on the region of interest. When attempting to do so, the decoded results don't follow the zoom change.
To illustrate, the first attachment is a capture of a single I2C transaction. The micro's software does the transaction only once, so the scope is not re-triggered. Triggering is set to 'normal'. The decode looks fine. I then use the horizontal position to move the traces. Note that the decode results don't follow. I can also change the horizontal timebase, and the decoded results still don't match up.
I also noticed that if I change the horizontal timebase and make the micro do another I2C transfer, the scope captures it and displays it on the traces, but the bus decode does not change. If I do another transaction without touching the controls of the scope, it does the decode. Subsequent transfers are captured and decoded without error. It's as if the first transaction after changing the horizontal timebase isn't properly decoded. I noticed that this is only true of the horizontal timebase, not the horizontal position. It also happens when changing the memory depth (these images were all recorded at 7k, but the behavior is the same regardless of memory depth). It also behaves identically if I use the digital channels to read in the I2C bus.
From my earlier tests with Serial (UART) decode, I know that the scope handles zoom/pan properly when doing serial decode; it just doesn't seem to do so for I2C. Would be nice if they can roll this in to the next firmware update.