# HG changeset patch # User Mychaela Falconia # Date 1625335856 0 # Node ID bdc5d8d9fa1fec711730c2a42127f570c6d4cb1b # Parent ed686a290f2de296185ca8a7c3b9b162c61ee5f9 FC-handset-spec: new section 1.10.1 clarifies battery ID resistor/thermistor situation diff -r ed686a290f2d -r bdc5d8d9fa1f FC-handset-spec --- a/FC-handset-spec Sat Jul 03 07:01:39 2021 +0000 +++ b/FC-handset-spec Sat Jul 03 18:10:56 2021 +0000 @@ -730,6 +730,24 @@ even worse, as their discharge curve is said to be even flatter. For these reasons, we are going to play it safe and stick with Li-ion. +1.10.1. Battery ID resistors or thermistors + +In all classic dumbphones from the era which we seek to revive (the ones with +user-removable batteries), the battery pack (flat pouch) has 3 or 4 contacts +rather than just 2: in addition to battery +ve and -ve terminals, there are some +ID resistors or thermistors included. Both Motorola C1xx and Pirelli DP-L10 +batteries have 3 contacts, and so does Nokia BL-6C battery form factor that was +copied by FIC/Openmoko. In contrast, cylindrical Li-ion battery cells like +18650 have no such third terminal. + +Because we are deferring our handset battery design to a later project phase +(not included on the Venus board), we don't know at this time whether or not +our final handset battery pack will have any ID resistor and/or thermistor +connected to Iota ADIN1 or ADIN2. Our current FCHG battery charging driver +does not touch ADIN1 or ADIN2 at all; if we do end up having an ID resistor or +thermistor and needing to support it, that custom support will have to be added +at the time of the actual handset design. + 1.11. Charging circuit Our FC Libre Dumbphone will feature a USB port (mini-B, device role only, no