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annotate sim-card-detect @ 371:c7514c8b5b41

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pirelli/headset: plug insertion detection figured out
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 14 Jun 2021 01:33:48 +0000
parents 82d5cc869bf1
children
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368
82d5cc869bf1 sim-card-detect observations note added
Mychaela Falconia <falcon@freecalypso.org>
parents:
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1 On the Mother's D-Sample board the SIM card status register (FFFE:0002)
82d5cc869bf1 sim-card-detect observations note added
Mychaela Falconia <falcon@freecalypso.org>
parents:
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2 reads:
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Mychaela Falconia <falcon@freecalypso.org>
parents:
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3
82d5cc869bf1 sim-card-detect observations note added
Mychaela Falconia <falcon@freecalypso.org>
parents:
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4 0x000A (CD bit 0) when the SIM socket is empty
82d5cc869bf1 sim-card-detect observations note added
Mychaela Falconia <falcon@freecalypso.org>
parents:
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5 0x000B (CD bit 1) when a card is inserted and the switch is shorted
82d5cc869bf1 sim-card-detect observations note added
Mychaela Falconia <falcon@freecalypso.org>
parents:
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6
82d5cc869bf1 sim-card-detect observations note added
Mychaela Falconia <falcon@freecalypso.org>
parents:
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7 These register readings match CAL207 register document.
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Mychaela Falconia <falcon@freecalypso.org>
parents:
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8
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Mychaela Falconia <falcon@freecalypso.org>
parents:
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9 On FCDEV3B Calypso SIM_CD input is tied high following Leonardo and Openmoko,
82d5cc869bf1 sim-card-detect observations note added
Mychaela Falconia <falcon@freecalypso.org>
parents:
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10 and the register reads 0x000B - thus we reach the conclusion that CAL000
82d5cc869bf1 sim-card-detect observations note added
Mychaela Falconia <falcon@freecalypso.org>
parents:
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11 document is correct in that logic high on SIM_CD is supposed to indicate SIM
82d5cc869bf1 sim-card-detect observations note added
Mychaela Falconia <falcon@freecalypso.org>
parents:
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12 inserted, whereas logic low is supposed to indicate an empty SIM socket.
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Mychaela Falconia <falcon@freecalypso.org>
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13
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Mychaela Falconia <falcon@freecalypso.org>
parents:
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14 However, the netlist extracted from the PADS PCB file for E-Sample (Calypso+
82d5cc869bf1 sim-card-detect observations note added
Mychaela Falconia <falcon@freecalypso.org>
parents:
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15 chipset) shows the opposite arrangement: it shows a pull-up resistor to V-IO on
82d5cc869bf1 sim-card-detect observations note added
Mychaela Falconia <falcon@freecalypso.org>
parents:
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16 the SIM-CD net, and the switch in the SIM socket shorts this net to ground.
82d5cc869bf1 sim-card-detect observations note added
Mychaela Falconia <falcon@freecalypso.org>
parents:
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17 Perhaps the sense of this signal is inverted on Calypso+? We have no way of
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Mychaela Falconia <falcon@freecalypso.org>
parents:
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18 knowing because we have no documentation for Calypso+, but we do know that its
82d5cc869bf1 sim-card-detect observations note added
Mychaela Falconia <falcon@freecalypso.org>
parents:
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19 ABB companion Syren reversed the sense of its test reset signal (relative to
82d5cc869bf1 sim-card-detect observations note added
Mychaela Falconia <falcon@freecalypso.org>
parents:
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20 Iota) for no apparent reason, hence such signal polarity reversals are not out
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Mychaela Falconia <falcon@freecalypso.org>
parents:
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21 of the question.