FreeCalypso > hg > freecalypso-docs
comparison FC-handset-spec @ 68:bdc5d8d9fa1f
FC-handset-spec: new section 1.10.1 clarifies battery ID
resistor/thermistor situation
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Sat, 03 Jul 2021 18:10:56 +0000 |
| parents | ed686a290f2d |
| children | c6dafe9f3ac2 |
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| 67:ed686a290f2d | 68:bdc5d8d9fa1f |
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| 728 already somewhat challenging even with Li-ion, given the relatively flat middle | 728 already somewhat challenging even with Li-ion, given the relatively flat middle |
| 729 part of the discharge curve - and with NiMH we can only expect the problem to be | 729 part of the discharge curve - and with NiMH we can only expect the problem to be |
| 730 even worse, as their discharge curve is said to be even flatter. For these | 730 even worse, as their discharge curve is said to be even flatter. For these |
| 731 reasons, we are going to play it safe and stick with Li-ion. | 731 reasons, we are going to play it safe and stick with Li-ion. |
| 732 | 732 |
| 733 1.10.1. Battery ID resistors or thermistors | |
| 734 | |
| 735 In all classic dumbphones from the era which we seek to revive (the ones with | |
| 736 user-removable batteries), the battery pack (flat pouch) has 3 or 4 contacts | |
| 737 rather than just 2: in addition to battery +ve and -ve terminals, there are some | |
| 738 ID resistors or thermistors included. Both Motorola C1xx and Pirelli DP-L10 | |
| 739 batteries have 3 contacts, and so does Nokia BL-6C battery form factor that was | |
| 740 copied by FIC/Openmoko. In contrast, cylindrical Li-ion battery cells like | |
| 741 18650 have no such third terminal. | |
| 742 | |
| 743 Because we are deferring our handset battery design to a later project phase | |
| 744 (not included on the Venus board), we don't know at this time whether or not | |
| 745 our final handset battery pack will have any ID resistor and/or thermistor | |
| 746 connected to Iota ADIN1 or ADIN2. Our current FCHG battery charging driver | |
| 747 does not touch ADIN1 or ADIN2 at all; if we do end up having an ID resistor or | |
| 748 thermistor and needing to support it, that custom support will have to be added | |
| 749 at the time of the actual handset design. | |
| 750 | |
| 733 1.11. Charging circuit | 751 1.11. Charging circuit |
| 734 | 752 |
| 735 Our FC Libre Dumbphone will feature a USB port (mini-B, device role only, no | 753 Our FC Libre Dumbphone will feature a USB port (mini-B, device role only, no |
| 736 OTG) that combines two logically separate functions: battery charging and | 754 OTG) that combines two logically separate functions: battery charging and |
| 737 computer interface. The basic idea of this dual-function USB port comes from | 755 computer interface. The basic idea of this dual-function USB port comes from |