FreeCalypso > hg > freecalypso-schem2
view venus/src/periph/loudspeaker.v @ 70:8bc2aa52fd23
manual RESET button new part: 260 g force, shorter actuator
One of the main envisioned use cases for FC Venus is field demonstration:
the board will be carried around, mounted on a sheet of acrylic or somesuch,
it will have a battery and an antenna connected, there will be a test SIM
with active service inserted, and the setup will be ready to demonstrate
as a working phone at a moment's notice. But when a demo is not actively
in progress, the fully assembled setup will be transported around in a big
and loose ESD bag, and it will need to be equivalent to a traditional phone
in its switched-off state: battery present, RTC keeping time, but not
switched on all the time.
Having a RESET button of the same keyswitch type as used for the regular
keypad and PWON would cause a problem for such field transport scenarios:
any spurious press of this button would cause a "misc boot" switch-on.
Short spurious presses of PWON are filtered out by the firmware (automatic
power-off if the button isn't held down long enough), but the same cannot
be done for super-low-level nTESTRESET. However, a button with significantly
greater operating force and a shorter actuator (not sticking out to the same
height as the regular keypad buttons) should be much safer.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Thu, 02 Dec 2021 22:40:39 +0000 |
parents | 66d99b5be8a3 |
children |
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/* Loudspeaker circuit following Leonardo schematics */ module loudspeaker (GND, VBAT, Input_pos, Input_neg, GPIO_enable); input GND, VBAT; input Input_pos, Input_neg; input GPIO_enable; wire PA_in_pos, PA_in_neg; wire Out_pos, Out_neg; wire BYPASS; /* instantiate the audio PA */ pkg_TPA6203A1 apa (.BYPASS(BYPASS), .GND(GND), .In_neg(PA_in_neg), .In_pos(PA_in_pos), .SHUTDOWN(GPIO_enable), .VDD(VBAT), .Out_pos(Out_pos), .Out_neg(Out_neg) ); /* input resistors: the inversion is per Leonardo schematics */ resistor R33xA (Input_pos, PA_in_neg); resistor R33xB (Input_neg, PA_in_pos); /* feedback resistors */ resistor R331 (Out_neg, PA_in_pos); resistor R332 (Out_pos, PA_in_neg); /* bypass and supply decoupling caps */ capacitor C319 (BYPASS, GND); capacitor C330 (VBAT, GND); /* small output capacitors */ capacitor C331 (Out_neg, GND); capacitor C332 (Out_pos, GND); /* the speaker itself! */ header_2pin spkr_connector (Out_pos, Out_neg); /* pull-down on the GPIO control line */ resistor R338 (GPIO_enable, GND); endmodule