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FC-handset-spec: BCI header change on Venus
author Mychaela Falconia <falcon@freecalypso.org>
date Sat, 03 Jul 2021 19:53:22 +0000
parents bdc5d8d9fa1f
children eb68975e1b81
comparison
equal deleted inserted replaced
68:bdc5d8d9fa1f 69:c6dafe9f3ac2
1368 1368
1369 For development and testing of handset battery management in the firmware, and 1369 For development and testing of handset battery management in the firmware, and
1370 for exercising the charging boot path in particular, Iota VCHG needs to be 1370 for exercising the charging boot path in particular, Iota VCHG needs to be
1371 brought out like it is on iWOW DSK and FC Caramel2 boards, to be connected with 1371 brought out like it is on iWOW DSK and FC Caramel2 boards, to be connected with
1372 a jumper wire to +5V pin on the DUART28 USB adapter whenever a "charger plugged" 1372 a jumper wire to +5V pin on the DUART28 USB adapter whenever a "charger plugged"
1373 condition needs to be presented to the chipset. FC Venus will feature a 2x4 pin 1373 condition needs to be presented to the chipset. FC Venus will feature a 2x3 pin
1374 header with Iota BCI signals like on Caramel2: 1374 header with Iota BCI signals as follows:
1375
1376 VBATS VCCS
1377 PCHG VCHG
1378 ICTL GND
1379
1380 Please note that this planned BCI header pinout differs from iWOW DSK and FC
1381 Caramel2, which implement the following 2x4 pinout instead:
1375 1382
1376 ICTL VCCS 1383 ICTL VCCS
1377 PCHG VCHG 1384 PCHG VCHG
1378 ADIN2 ADIN1 1385 ADIN2 ADIN1
1379 GND GND 1386 GND GND
1383 in which case the board remains powered from a fixed DC supply (no actual 1390 in which case the board remains powered from a fixed DC supply (no actual
1384 battery) and only VCHG needs to be connected. However, if a need arises to 1391 battery) and only VCHG needs to be connected. However, if a need arises to
1385 connect an actual battery and an actual Iota-controlled charging circuit, it 1392 connect an actual battery and an actual Iota-controlled charging circuit, it
1386 will be possible: the battery will need to be connected to the orange power 1393 will be possible: the battery will need to be connected to the orange power
1387 input connector, and the control signals for the charging circuit will need to 1394 input connector, and the control signals for the charging circuit will need to
1388 be connected to the 2x4 header. 1395 be connected to the 2x3 header.
1396
1397 The Mother's vision is that if and when we do need to exercise an actual Li-ion
1398 battery with an actual Iota-controlled charging circuit, we will need to build
1399 a separate battery+charger board that will connect to the power input and BCI
1400 control interfaces on the Venus board. That battery+charger board will feature
1401 an 18650 battery holder and a +5V charging power source connection, the charging
1402 current path (aside from BCI controls) will be contained entirely in that add-on
1403 board, whereas the battery power interface between Venus and the add-on board
1404 will carry only the load or discharge current.
1405
1406 The reasons for changing the BCI header pinout from iWOW DSK and FC Caramel2 to
1407 a different one for FC Venus are as follows:
1408
1409 * FC Tango (iWOW TR-800) module that forms the core of FC Caramel2 does not
1410 bring out Iota VBATS as a separate signal - instead it is connected to the
1411 VBAT supply inside the module. However, if the charging current measurement
1412 resistor will reside on a separate battery+charger board, then it would be
1413 most proper to connect both VBATS and VCCS to the two sides of this resistor,
1414 providing more accurate charging current measurement and CI control loop
1415 operation. Thus VBATS needs to be added to the BCI header.
1416
1417 * ADIN1 and ADIN2 won't be needed when using a common off-the-shelf 18650
1418 battery for prototyping - see section 1.10.1 for background information.
1389 1419
1390 3.5. LCD module and backlight 1420 3.5. LCD module and backlight
1391 1421
1392 The Mother's original intent was to finalize the selection of LCD module for the 1422 The Mother's original intent was to finalize the selection of LCD module for the
1393 actual handset before embarking on the detailed design (as in schematics, BOM 1423 actual handset before embarking on the detailed design (as in schematics, BOM