Subj : Re: RP2040 reset idea To : All From : john larkin Date : Tue Sep 17 2024 07:10:39 XPost: sci.electronics.design On Tue, 17 Sep 2024 12:16:55 +0800, Sylvia Else wrote: >On 17-Sept-24 10:58 am, john larkin wrote: >> The RP2040 has a cool mode where it can be made to boot up with the >> USB port looking like a memory stick. That's great for software >> installs or upgrades. The Pico board has a BOOT button on the board; >> if the pico is powered up with the button pushed, it goes into that >> boot mode. >> >> But if I have a product (actually a family of products) in a nice >> aluminum box, a user would have to remove the top cover, remove all >> power sources (there can be three), and hold the button down while >> reconnecting power. >> >> Some of my customers also want to lock a box such that it's impossible >> to write to any nonvolatile memory while it's in a secure area. >> >> So here's an idea: a small hole in the box allows a toothpick or a >> paper clip to push a button. A short push is a regular reset. A long >> push is a memory-stick mode boot. We can have a rotary switch LOCK >> hole too. >> >> https://www.dropbox.com/scl/fi/bbhdy053xsdzv77g0brc5/B-box_Reset_Button_3.jpg?rlkey=40ozzdvczf4z8625u8i081a9b&raw=1 >> >> Does that look like it will work? The paranoid customer can pave over >> the two holes, and even the end-plate screws, with an official-looking >> sticker. >> >> Schmitt trigger U3 is unfortunate and likely unnecessary, but it >> insures against a low-probability hazard. >> > >If the board needs to be powered up, rather than just reset, while the >button is pressed, then how does your solution work? If not, then why is >the fact that there are three power supplies relevant? > >Sylvia. Asserting BOOT- (or pushing the button on the Pico board) at the end of reset should launch it into boot mode. On the Pico board, asserrting RESET- is done by cycling the power. My user might have to remove all three power sources (PoE, 24 volt wart, USB) to force a reset, if we did the boot button like the Pico does. --- SoupGate-Win32 v1.05 * Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3) .