Scope utility on google code

That ought to have been easier than it was. It's not that it's difficult, there are hints everywhere. Given the hints, the first things I thought of happened to be wrong almost every time. Oh well, the scope utility is available for download from Google code hosting. The source is also available at http://code.google.com/p/gds2062/.

Past my bedtime again. Perhaps just a few morsels:

C2 snooping

Was having trouble correctly reading the C2 traffic between the IDE and the microcontroller. Extracting the sample points using the java utility and plotting with GNUPlot, it's obvious that the C2K (clock) strobe leads the C2D (data). Looking at the C2 Interface specification from Silicon Labs, I see that... that's what the manual said all along. A small change to the C2-reading code, and the utility seems to get the snoop right on all the datasets (not many) I've tried so far. I did try straining my brain first - I was expecting C2D to be setup before the strobe leading edge, perhaps triggered by the strobe's falling edge. But it isn't. Should have RTFS.

Problem with GW Instek GDS-2062 command language

I sent an email off to Instek in the U.S. (I think) today. There's one guy who works for them, that answered once. That's when I was told there would be a firmware update in February. I'm still waiting for it. I think it's going to be a good one. Instek have a lot of websites, with a lot of email addresses and contact forms. I must have sent half a dozen messages or so when I first got this scope to ask for help. Not a dicky bird. Except for the aforementioned bloke. So I've sent him a couple more. This latest one is about the USB/serial port command language for the setting the time/div. You use :TIMEBASE:SCALE and provide a floating point number like 2.5e-3 to get 2.5ms per division on the oscilloscope screen. Only it doesn't always select the right settings - probably a typo in the firmware code, I suspect. Here's the list copied verbatim from my email:

Command (Result)
:TIMEBASE:SCALE 1e-3 (1ms) correct
:TIMEBASE:SCALE 2.5e-3 (1ms) wrong!
:TIMEBASE:SCALE 5e-3 (2.5ms) wrong!
:TIMEBASE:SCALE 10e-3 (5ms) wrong!
:TIMEBASE:SCALE 25e-3 (25ms) correct
:TIMEBASE:SCALE 50e-3 (50ms) correct
:TIMEBASE:SCALE 100e-3 (50ms) wrong!
:TIMEBASE:SCALE 250e-3 (250ms) correct

If you're doing something with a GDS-2062 via the USB/serial port, you might run up against this feature!

That's it. Bed calls.