Thank you for looking for an alternative, i’ll look into it. But for now, I managed to squeeze an ATTiny25v on there, so bistro-hd would be possible.
The springpad is now smaller, but it should work (6.4mm diameter or so). It was possible because the ATTiny has one side of pins without any connection, so I removed these solder connections. On the other side, I just left the gnd pin.
One problem with other MCUs is that you have to change a lot in the code to make it run, so I hope it works like it is now.
I hope the 25v in a qfn package is a rev E at mouser. This is required to be able to run bistro-hd.
But since it’s a driver where a lot of current could flow, I maybe won’t even solder a spring on there. A piece of brass/copper could also work, and needs no bypass.
Ok, I finally found my way to thread instead of just the backroom PM discussions (that there have been a bunch of). Subscribed.
FWIW I've worked up a "Fet only" (ie single channel) configuration of bistro-HD (will be in next release, soon). Been meaning to anyway (actually a few such configurations, switch, indicator, OTMS, etc). It took a little compromising to match ramps to TA modegroups, mostly because without a 7135 you can't go below 11mA (1/255 * 2.8A) so modes get cutoff, but I've been thinking of ways to get around it.
16bit PWM, if the converter can actually handle such output or true, 2nd channel, enable pin PWM reduction, but Schoki says it's hard to fit the trace. 11mA ain't too bad though. It's not really moon, but it's low.
I thought I heard that this was going toward an attiny25 qfn, which I think is also on the scale of 3mm. Anyway, if you can make it still flashable (soic as shown), that's great.
For software though, if you need more space, the qfn becomes a drop-in replacement from the software side. Of course the qfn might make room for that extra trace.
It is attiny25 qfn, the tiny is on the underside. I removed the pads that aren’t connected internally of the attiny, the springpad is now a little bit bigger.
You need 5 wires to flash. (power, ground, miso, mosi, sck) You're soldering them all by hand? Wow.
At some point it would probably be worth drawing a flashing board, that just connects via headers to the chip. It's got to be faster to just reflow it. Of course that requires work too.
So for testing it's actually possible to flash with debug wire, using only 3 pins. Two of those are power and ground. One is reset. So you could solder a wire to just reset on the board if you leave a small pad.
BUT, that uses debugwire, you'll have to flash fuses for that first anyway, and those fuses disable power-down sleep, which means OTSM won't work, so, so much for testing really. Could be useful for rapid e-switch testing, but not a very viable all around replacement.