Thanks for your explanations. That's all I really have to say after that mail.
On Fri, Jan 12, 2018 at 10:29:14AM +0000, Luke Kenneth Casson Leighton wrote: [...]
- If the CPU card spontaneously resets without first bringing the housing into a state where it tolerates early debug output (some housings might require such preparation before shutdown).
exactly. and that is far too complicated. right now there is *zero* need - at all - for *any* kind of complexity on the Housings. the Micro-Desktop is.... it's just a bunch of connectors. as in, that's *all* that's needed.
I wasn't aware housings tend to be *this* simple.
Here's a *completely different* and significantly simpler proposal, which also fulfills these goals. You probably won't like it because (a) it takes away a pin from general purpose use, (b) it breaks compatibility [see footnote 1] with current hardware.
Replace one of the GPIO pins (such as pin 21, GPIO 20) with a single- purpose Debug UART TX pin, where the CPU card may print debug messages in 8N1 format. Debug UART TX high/low is measured against VREFTTL.
nope. not enough pins. you're thinking in terms of prioritising "Technical End-User" over "End-User".
the volume of sales to "End User" is intended to be HUNDREDS OF MILLIONS.
the volume of sales to "Technical End User" is expected to measure in the thousands.
Ok, makes sense. That's a valid design point.
Thanks, Jonathan Neuschäfer