Small-footprint Due
hi guys -
need expert feedback on due board designing.
we wanted build smallest possible footprint due-compatible board embedding our products (such our open source ev charging stations, ev chargers, etc - info curious ones: http://www.emotorwerks.com/products/online-store/product/show/44-emw-juicebox-level-2-15kw-ev-charging-station-kit-or-assembled-unit).
we have sifted through posts find on various relevant topics try collect gotchas (e.g., errors in schematics, suboptimal i2c pullup resistor values). have looked various types of user feedback design board can not useful interesting others making small production runs based on sam3x8e. e.g. have added 64kbit eeprom on board, broken out aref pin, etc.
at moment, able 4-layer layout containing lqfp-144 package fit 1.2"x1.4" footprint. have external programming board due programming circuit on it. way small production runs way more economical don't have spend $$ , board space on programmer circuits don't use in production.
see screenshot below details. picture admittedly bit messy layers visible - sam chip mounted on top of board, other components - on bottom. 68 .1" pins on perimeter. main design objective smallest footprint while maximizing number of peripheral types broken out. trade-off smaller number of broken-out digital i/o pins. notice there no reset / erase buttons. again, not expect useful in production environment. , take huge amount of space + cost of electromech components non-trivial.
in addition general feedback, cool hear opinion on open questions still have:
* should vbus / uotgvbof / vbg lines? not breaking out native usb @ point none of usb hardware used wondering need keep original due schematics system still works. e.g., should provide vcc vbus input? should still have rc network on vbg pin? etc.
* should try break out native usb? reason it's not on right micro-ab slot take 20% of our board space , in fact make board @ least 40% larger. enough space benefit having microdue board diminished. unless 1 can see extremely high utility native usb, keep out. imo given there going separate programmer board, native usb useful usb host mode. not sure % of target users important for. maybe missing uses other usb host?
* there other gotchas should aware of?
thoughts? want this? ;-)
thanks,
valery.
need expert feedback on due board designing.
we wanted build smallest possible footprint due-compatible board embedding our products (such our open source ev charging stations, ev chargers, etc - info curious ones: http://www.emotorwerks.com/products/online-store/product/show/44-emw-juicebox-level-2-15kw-ev-charging-station-kit-or-assembled-unit).
we have sifted through posts find on various relevant topics try collect gotchas (e.g., errors in schematics, suboptimal i2c pullup resistor values). have looked various types of user feedback design board can not useful interesting others making small production runs based on sam3x8e. e.g. have added 64kbit eeprom on board, broken out aref pin, etc.
at moment, able 4-layer layout containing lqfp-144 package fit 1.2"x1.4" footprint. have external programming board due programming circuit on it. way small production runs way more economical don't have spend $$ , board space on programmer circuits don't use in production.
see screenshot below details. picture admittedly bit messy layers visible - sam chip mounted on top of board, other components - on bottom. 68 .1" pins on perimeter. main design objective smallest footprint while maximizing number of peripheral types broken out. trade-off smaller number of broken-out digital i/o pins. notice there no reset / erase buttons. again, not expect useful in production environment. , take huge amount of space + cost of electromech components non-trivial.
in addition general feedback, cool hear opinion on open questions still have:
* should vbus / uotgvbof / vbg lines? not breaking out native usb @ point none of usb hardware used wondering need keep original due schematics system still works. e.g., should provide vcc vbus input? should still have rc network on vbg pin? etc.
* should try break out native usb? reason it's not on right micro-ab slot take 20% of our board space , in fact make board @ least 40% larger. enough space benefit having microdue board diminished. unless 1 can see extremely high utility native usb, keep out. imo given there going separate programmer board, native usb useful usb host mode. not sure % of target users important for. maybe missing uses other usb host?
* there other gotchas should aware of?
thoughts? want this? ;-)
thanks,
valery.
this interesting.
how think cost every assembled board?
how think cost every assembled board?
Arduino Forum > Products > Arduino Due (Moderator: fabioc84) > Small-footprint Due
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