On Sat, 1 Dec 2018, alan--- via cctalk wrote: > I'm not sure what the 'B' in the middle means (silicon rev?), but the DS12885 > has been around for decades. I use them the JR-IDE project.
Yes, the DS12885 is a standard part, still in production (with a trailing + marking RoHS compliance). According to its datasheet the DS12B887 has an NC pin actually present in the position where the DS12885 has the RESET# line, while the remaining NC positions are absent due to the respective pins having been bent up (or "are missing by design", as the datasheet puts it). So either a different core had to be used with the DS12B887 or the datasheet has an error. However RESET# would have to be connected to VCC for normal operation and there is no mention of an internal pull-up on RESET# with the DS12885, so I take it the DS12B887 had to use a different core and a DS12B885 seems like a logical match. The placement of RESET# right in the middle between VBAT and GND makes it highly unlikely an internal discrete connection has been made in the DS12B887 package between RESET# and VCC, as a shortage to the embedded lithium cell from that pin if bent up and soldered to would be virtually unavoidable. Maciej
