wight wrote: . . .
- First of all, looks like neat stuff. As you all know, any move to physically larger MCUs is a pain for the CAD folks – so I tend to resist that change. If it nets us nice thermal protection features though, I’ve got to be game! As usual I’d prefer to try cramming in the 20M1 package with ISP headers for programming. . . .
- Tom E – did you ever get a handle on the calibration points you wanted? 0c and 100c are easy to reliably achieve using ice-water and boiling-water so those are common at-home calibration points. Atmel bins some chips (not the ones we buy) for 105c and 125c, I think it’s fair to say that all of them are going to be OK at 100c long enough for a one-time calibration routine. Just throw the light in a plastic bag and drop it in for a while, right?
- I wonder how much better an LDO driver would fair with the stuff mentioned in post #601 by Tom E. I did publish an LDO driver a while ago – it’s probably suitable for testing. A17DD-SO8+LDO
I've been pushing for keeping the SSU footprint on the boards and just bending the legs. It really makes it easier to position the programming clip and the hold is much better. Those that have tried it have reported positive experiences so far.
I don't think temperature read calibration is worth the effort. Each light is going to behave differently anyway due to many factors. User adjustable seems the best approach to dealing with all the variables.
I think you may be on to something with LDO, I've been putting my 25/45/85's in buck and LDO (at opposed to zener modded) DD drivers and haven't had any issues yet, but I'm also using an older version of Tom E's FW for the 25/45/85. Unfortunately, the LDO I use is for 2S and higher cell arrangements only.
EDIT: Another benefit of bending the legs (which is easy) and is that the MCU stands higher. It allows low profile components like resistors and small caps to be placed right up to the legs, if necessary. Resistors could even go under the MCU.